//! Editor module, generic over Language.
const std = @import("std");
const build_options = @import("build_options");
const AST = @import("ast/ast.zig");
const Document = @import("document.zig");
const Span = @import("util/span.zig");
const json = @import("languages/json/json.zig");
const json_string = @import("util/json_string.zig");
const regions = @import("editor/regions.zig");
/// The hook-facing surface: the source-coordinate utilities the engine, the
/// regions module and every format's hooks share. Re-exported here for the
/// engine's own use; a hook imports `editor/splice.zig` directly.
const splice = @import("editor/splice.zig");
const lineStartBefore = splice.lineStartBefore;
const lineEndAfter = splice.lineEndAfter;
const firstNonSpace = splice.firstNonSpace;
const columnOf = splice.columnOf;
const isFlow = splice.isFlow;
const CommentStyle = splice.CommentStyle;
const commentBlockStart = splice.commentBlockStart;
const appendBlockSep = splice.appendBlockSep;
const Block = splice.Block;
const tileBlocks = splice.tileBlocks;
const fullOrder = splice.fullOrder;
const Region = regions.Region;
const log = std.log.scoped(.editor);
// The declared half of the Language interface — `Syntax`, `Caps`,
// `CommentStyle`. Every surface-syntax parameter this engine used to select
// with an `if (Language == X)` branch now comes from `Language.syntax(t)`
// instead; see `languages/manifest.zig` and
// `docs/proposals/language-interface.md`. A leaf module, so importing it here
// (and from every `<lang>/<lang>.zig`) pulls in nothing else.
const lang = @import("languages/manifest.zig");
// The OPERATIONS half of the interface — the part `syntax` can't express.
//
// Where a format's editing need is a value (a separator, a marker, whether
// block sequences are editable), it is declared on `Language.syntax` and read
// above. Where it is LOGIC, the format declares a hook: a `pub` decl on its
// `Language` struct named for the operation it takes over. This engine
// dispatches on presence —
//
// if (@hasDecl(Language, "insertKey")) return Language.insertKey(...);
//
// — so it names no format at all. Each hook's signature is fixed by its one
// call site and documented on the method it overrides; the implementations
// live in `<lang>/editor_helper.zig` (which also holds that language's editor
// tests, so editor-test code sits next to the concern it exercises), and the
// DECLARATION of which operations a format overrides, with the reason, sits in
// the "Editing hooks" block of its `<lang>/<lang>.zig`. See
// `docs/proposals/language-interface.md`.
//
// What remains below is what hook dispatch does not reach:
//
// * `zon_edit.appendFieldName` is reached through `key_style`, as the
// rendering half of a syntax parameter rather than an operation override.
// * The bare language tags below are used by this file's OWN tests, nothing
// else. The EXCLUSIVE whole-container operations (see that block) used to
// need `Language != Toml`/`!= Fig` guards and direct imports of those two
// formats' helper modules; they are `@hasDecl`-dispatched now, like every
// hook, so this file names no format outside its tests. Zig still has no
// conditional container-level declarations (`usingnamespace` was removed in
// 0.15), so the methods exist for every format and refuse at comptime —
// but on a missing declaration rather than on a format's identity.
const zon_edit = @import("languages/zon/editor_helper.zig");
const Toml = @import("languages/toml/toml.zig").Language;
const Fig = @import("languages/fig/fig.zig").Language;
const Yaml = @import("languages/yaml/yaml.zig").Language;
const Zon = @import("languages/zon/zon.zig").Language;
const Dotenv = @import("languages/dotenv/dotenv.zig").Language;
const Properties = @import("languages/properties/properties.zig").Language;
const Ini = @import("languages/ini/ini.zig").Language;
const Plist = @import("languages/plist/plist.zig").Language;
const NestedText = @import("languages/nestedtext/nestedtext.zig").Language;
pub fn Editor(comptime Language: type) type {
@import("languages/language.zig").validate(Language);
return struct {
const Self = @This();
/// Everything this format declares about its own surface syntax, for
/// the dialect the document is currently being read as. Replaces the
/// per-language `if (Language == X)` parameter branches this file used
/// to carry — the values now live on `<lang>/<lang>.zig`, checked by
/// `language.validate`. See `languages/manifest.zig`.
///
/// Indexed by `self.format` rather than fixed at comptime because the
/// comment markers genuinely vary by dialect (strict JSON has no
/// comment syntax; JSONC and JSON5 do), and every splice is reparsed
/// under whichever dialect the editor is holding. The rest of the
/// struct is dialect-invariant today; a TOML 1.0/1.1 or YAML
/// 1.1/1.2.2 *editing* divergence would land here if one appeared.
///
/// Cost is one runtime switch and it stops there: every consumer is an
/// `appendSlice` or an argument to `commentBlockStart`/
/// `entryBlockStart`, none of which needs a comptime value.
fn syntax(self: *const Self) lang.Syntax {
return Language.syntax(self.format);
}
/// Whether `path`'s final segment names a key the document RESOLVES but
/// no physical entry declares — one supplied by the format's reference
/// layer, which path navigation does not follow and therefore reports
/// as `NotFound`.
///
/// **Hook** `keyIsInherited(parsed, path) !bool`. Declared by YAML
/// alone, where a `<<` merge supplies keys its own mapping never spells
/// out. With no hook the answer is false, which is correct for every
/// format that has no reference layer — so the two `NotFound` recovery
/// sites below need no language test of their own.
///
/// A predicate rather than a recovery hook, because only the QUESTION
/// is the language's: `replaceValAtPath` answers it by shadowing the
/// inherited key with a local entry (copy-on-write) and `deleteKey` by
/// refusing outright, and both of those policies are generic.
fn keyIsInherited(parsed: Document, path: []const AST.PathSegment) !bool {
if (!@hasDecl(Language, "keyIsInherited")) return false;
return Language.keyIsInherited(parsed, path);
}
allocator: std.mem.Allocator,
source: std.ArrayList(u8) = .empty,
document: ?Document = null,
format: Language.Type = Language.default_type,
/// Set by `replaceAtSpan` when the reparse it does after splicing
/// FAILED — i.e. the caller's replacement text, not the document it
/// went into, is what doesn't parse (the document parsed at `init`,
/// and every edit routes through that one splice gate). The error
/// itself can't say this: it is an ordinary parse error, identical to
/// what a malformed input file produces. Callers that hand a user's
/// raw text through — the CLI's `edit`/`set`/`insert` — read this to
/// blame the text instead of the file. Cleared at the top of each
/// splice, so it always describes the most recent one.
splice_rejected: bool = false,
pub fn getParsed(self: *const Self) !Document {
return self.document orelse {
log.err("Not initialized!", .{});
return error.NotInitialized;
};
}
pub fn init(self: *Self, input: []const u8) !void {
if (self.source.items.len != 0 or self.document != null) return error.MultipleInit;
try self.source.appendSlice(self.allocator, input);
self.document = try self.parseSource();
}
/// Replace a span with a new span. Atomic: on success `self.document` is
/// the reparse of the edited source; if the edit produces source that no
/// longer parses, the source is rolled back and the prior `self.document`
/// stays valid, so a failed edit leaves the editor exactly as it was.
pub fn replaceAtSpan(self: *Self, span: Span, replacement: []const u8) !void {
// Snapshot the whole source so a failed reparse can be undone. The
// edit already costs a full reparse, so an O(n) copy is negligible.
const backup = try self.allocator.dupe(u8, self.source.items);
defer self.allocator.free(backup);
self.splice_rejected = false;
try self.replaceSource(span, replacement);
self.reparse() catch |err| {
// Restore byte-for-byte. Capacity is retained from before the
// edit (>= backup.len), so the refill cannot fail.
self.source.clearRetainingCapacity();
self.source.appendSliceAssumeCapacity(backup);
// `backup` parsed at `init`, so the only new thing in the
// buffer was `replacement`: it is what `err` is about.
self.splice_rejected = true;
return err;
};
}
/// Replace the value at `path`. Reference-layer behavior is copy-on-write:
/// editing a value that is an alias (`b: *x`) replaces the `*x` text with
/// the new literal (severing only that alias — its anchor and any other
/// alias are untouched), which falls out of splicing the alias node's own
/// span. A key supplied only by a `<<` merge is materialized locally,
/// shadowing the merge. Use `replaceValAtPathFollowing` to edit through to
/// a shared anchor instead.
///
/// **Hook** `replaceValAtPath(self, parsed, path, node, span,
/// replacement) !void` — replaces the splice below wholesale, for a
/// format where `replacement` cannot go into the old value's slot
/// verbatim. Two distinct reasons, both declared:
///
/// * The slot is not a bare literal. plist wraps every value in a
/// typed element (`<integer>42</integer>`), and NestedText frames
/// one either rest-of-line or as a nested `>`-block — so the text
/// has to be RENDERED, not spliced.
/// * The slot's shape can change. YAML and fig re-emit the whole
/// `key<sep>value` so a block collection can descend onto the
/// following lines where the old value was inline (`k: []` → a
/// block list), which a span splice cannot express. Both take the
/// direct splice for a non-mapping target, inside the hook.
///
/// A hook receives the resolved `node` and its `span`, so it never
/// repeats the path walk; a format that declares none (JSON, TOML, ZON,
/// INI, dotenv, `.properties`) has a literal syntax that splices
/// verbatim in place — for every target it can address at all, which for
/// TOML and INI is what the guard below decides.
///
/// **Engine rule**, not a hook: a SECTION node — one the parser
/// recorded header lines for (`Document.node_regions`) — is refused
/// before the generic splice runs (`CannotReplaceTable` /
/// `CannotReplaceSection` / `CannotReplaceContainer`, in the format's
/// own vocabulary). In TOML and INI a container's node span is only
/// its KEY segment inside a `[header]` (or a dotted `a.b = 1` key)
/// rather than any value text: a container's body is assembled from
/// lines the span never covers, so splicing `replacement` into that
/// span would rewrite the header's NAME and silently rename the
/// section. The rule guards the engine's own splice only: a format
/// that hooks `replaceValAtPath` has taken that splice over and owns
/// its targets (fig re-frames a block container's value in place, so
/// its sections stay replaceable through the hook). The
/// whole-container ops (`deleteContainer`, `renameContainer`, …) are
/// what handle a section otherwise.
pub fn replaceValAtPath(self: *Self, path: []const AST.PathSegment, replacement: []const u8) !void {
const parsed = try self.getParsed();
const node = parsed.ast.getValByPath(path) catch |err| {
// An inherited key surfaces as NotFound (path nav doesn't follow
// the reference layer); copy-on-write it by inserting a local
// `key: value` entry that shadows what it inherits from.
if (err == error.NotFound and try keyIsInherited(parsed, path)) {
try self.insertKey(path[0 .. path.len - 1], path[path.len - 1].key, replacement);
return;
}
return err;
};
const span = parsed.span(node);
if (@hasDecl(Language, "replaceValAtPath"))
return Language.replaceValAtPath(self, parsed, path, node, span, replacement);
// The engine's veto, before anything is spliced — a target whose
// span is a header/dotted KEY, not a value slot. The root is let
// through: its span is the whole document, which is exactly what
// replacing the root means.
if (path.len > 0 and parsed.isSection(node)) return self.refuse(.replace);
try self.replaceAtSpan(span, replacement);
}
/// Upsert a mapping value: replace the value at `path`, or — when only
/// the trailing key is absent — insert it as a fresh `key: value` entry
/// in the parent mapping. This is the "set this key, creating it if
/// missing" primitive every config editor reaches for; it folds the
/// usual `replaceValAtPath` → (on `NotFound`) `insertKey` two-step into
/// one op.
///
/// The path's last segment MUST name a key — `set` only ever *creates* a
/// mapping entry, never a sequence item, so a path ending in an index is
/// rejected with `NotAMapping`. Missing *intermediate* containers are
/// auto-vivified (`mkdir -p` for config): if the parent mapping doesn't
/// exist yet, `set` seeds it — and any of ITS missing ancestors, deepest
/// first — as an empty map, then lands the leaf. Vivification fires when
/// an intermediate key is genuinely absent (`NotFound`), or when what
/// stands in its place is an EMPTY node — a null, i.e. a bare `key:` or an
/// empty document's root, which is a container waiting to exist. A
/// segment that resolves to a non-map SCALAR is a real type error
/// (`NotAMapping`) and is never clobbered. See `Syntax.empty_map_literal`
/// for what a seed is spelled as per format (YAML block, flow `{}`
/// elsewhere).
///
/// Vivify-then-land is atomic as a whole: if the leaf cannot be placed
/// after a seed has been spliced, the seed is rolled back, so a failed
/// `set` leaves the document byte-for-byte as it was. Where the seeds are
/// FLOW containers (every format but YAML) that has one consequence
/// callers see: a block-spelled value cannot land inside one, and is
/// refused with `BlockValueIntoFlow` rather than spliced into text that
/// no longer means what was written.
///
/// Delegates to `replaceValAtPath`, so the replace case inherits that
/// op's YAML value reframing (inline↔block) and merge-key COW.
///
/// Key duality: the replace branch matches the trailing segment
/// *logically* (against decoded key names), but the insert branch needs
/// the key as *syntax*. `set` bridges the two — when it inserts, it
/// renders the logical key into the format's key syntax (quoting/escaping
/// it for strict JSON, verbatim for YAML/TOML where a simple key already
/// is its own syntax) — so creating a not-yet-present key works for every
/// editable format, JSON included.
pub fn set(self: *Self, path: []const AST.PathSegment, value_text: []const u8) !void {
if (path.len == 0 or std.meta.activeTag(path[path.len - 1]) != .key)
return error.NotAMapping;
self.replaceValAtPath(path, value_text) catch |replace_err| {
// The value isn't there to replace — create it. The trailing key
// is logical (it just matched against decoded names), so render it
// into the format's key syntax before splicing. `insertKey`
// re-validates the parent (a mapping, or an empty/null root it
// promotes), so a non-mapping parent still errors; surface the
// original replace error when the insert can't proceed. Falling
// back on any replace error (not just `NotFound`) is what lets
// `set` seed a freshly-created, still-empty document — where
// navigating to the key fails with `NotAMapping`.
const key_text = try self.formatInsertKey(path[path.len - 1].key);
defer self.allocator.free(key_text);
self.insertKey(path[0 .. path.len - 1], key_text, value_text) catch |insert_err| {
// One insert failure is more informative than any replace
// error can be, so it is NOT swallowed by the fallback
// below: the parent was found and IS a mapping, just a flow
// one that cannot hold this value. Reporting the replace's
// `NotFound` there would send the caller looking for a
// missing key that isn't the problem.
if (insert_err == error.BlockValueIntoFlow) return insert_err;
// The parent mapping itself is missing (an intermediate key
// is absent — `NotFound`, NOT the `NotAMapping` of a scalar
// standing where a map should be, which must never be
// clobbered). Auto-vivify it as an empty map — recursing to
// seed any missing ancestor deepest-first — then retry the
// leaf insert into the now-existing parent.
//
// INI can't take part: `Syntax.empty_map_literal` is a value-literal
// sentinel (`{}`/`.{}`), and that spelling is only safe
// because it's ALSO genuinely valid syntax for "an empty
// mapping" in every other editable format (a real JSON
// object / YAML-TOML-fig flow map / ZON struct literal) —
// so vivifying through it can't produce anything wrong
// regardless of why it was reached. INI has no such
// literal (`{}` there is just a two-character STRING
// value; only a `[section]` header introduces real
// nesting), so blindly reusing the sentinel would splice
// a nonsense `section = {}` root key instead of a real
// section. Skip the vivify and surface the original
// `NotFound` — "no such section" — rather than corrupt.
// plist joins INI in opting out: `set`'s vivify seed is the
// flow `{}` literal, which plist has no reader for (an empty
// dict is `<dict/>`, not a value literal you can splice as
// `value_text`). Rather than teach the seed a plist spelling,
// surface the original `NotFound` — an intermediate `<dict>`
// must already exist to land a nested key.
// NestedText joins INI/plist here: the vivify seed is the
// flow `{}` literal, and while NestedText's reader DOES
// accept that as a genuinely empty (childless) mapping,
// this editor's own `ntInsertKey` declines to insert into
// one (see its module doc — expanding an inline `{}`
// into block form is deliberately out of scope) — so
// vivifying through it would only trade today's clear
// `NotFound` for a confusing `EmptyInlineContainer` one
// step later, after already splicing the `{}` in.
//
// `NotAMapping` joins `NotFound` as vivifiable in exactly
// one shape: when what stands in the way is an EMPTY node (a
// null), not a scalar. Navigating *through* a null fails the
// same way navigating through a scalar does, but they are
// opposite cases — a null is "nothing here yet" (an empty
// document's root, or a bare `key:`), which `insertKey`
// promotes to a real mapping, while a scalar is real data.
// Without this, a nested `set` on an empty document failed
// outright, though `set` is documented to seed one.
const vivifiable = insert_err == error.NotFound or
(insert_err == error.NotAMapping and
self.blockedByEmptyNode(path[0 .. path.len - 1]));
// A format with no `empty_map_literal` has no literal
// spelling for "an empty nested mapping" to seed WITH, so
// it cannot vivify at all — INI, plist and NestedText.
// The opt-out and the seed are one declaration because
// this is the literal's only consumer.
const seed = self.syntax().empty_map_literal;
if (seed != null and path.len >= 2 and vivifiable) {
// Vivify-then-insert is TWO splices, so it needs a
// snapshot of its own: each `replaceAtSpan` is
// individually atomic, but if the leaf insert fails
// after the ancestor seed landed, that seed is a
// half-finished edit no caller asked for — one that
// makes `Err` mean "nothing happened" a lie, and a
// retry an edit against an unexpected document.
// Restore, and report the failure as the whole `set`
// failing.
//
// Written as two `catch`es rather than one helper
// wrapping both splices: `set` recurses through the seed
// below, and routing that recursion through a helper
// makes the two functions' inferred error sets depend on
// each other (a comptime dependency loop).
const parent = path[0 .. path.len - 1];
const backup = try self.allocator.dupe(u8, self.source.items);
defer self.allocator.free(backup);
self.set(parent, seed.?) catch |seed_err| {
try self.restoreSource(backup);
return seed_err;
};
self.insertKey(parent, key_text, value_text) catch |leaf_err| {
try self.restoreSource(backup);
return leaf_err;
};
} else return replace_err;
};
};
}
/// Whether what blocks navigation to `path` is an EMPTY node — a null —
/// rather than real data. Walks back from `path` to the deepest prefix
/// that still resolves and reports whether that node is a null; an
/// unresolvable path with a null root (an empty document) counts too.
///
/// This is the distinction `set`'s vivify guard needs and `NotAMapping`
/// alone cannot make: a null is a container waiting to exist, which
/// `insertKey` promotes, while a scalar standing where a mapping should
/// be is data that must never be clobbered.
fn blockedByEmptyNode(self: *Self, path: []const AST.PathSegment) bool {
const parsed = self.getParsed() catch return false;
var len = path.len;
while (len > 0) : (len -= 1) {
const node = parsed.ast.getValByPath(path[0..len]) catch continue;
return node.kind == .null_;
}
return parsed.ast.nodes[parsed.ast.root].kind == .null_;
}
/// Restore the source to `backup` and reparse, undoing a compound
/// (multi-splice) op. `backup` is a snapshot of source that parsed, so
/// the reparse only fails on OOM. Capacity is retained from before the
/// edits (>= `backup.len`), so the refill cannot fail — the same
/// reasoning `replaceAtSpan`'s own rollback rests on.
fn restoreSource(self: *Self, backup: []const u8) !void {
self.source.clearRetainingCapacity();
self.source.appendSliceAssumeCapacity(backup);
try self.reparse();
}
/// Render a logical mapping key into this format's key syntax for the
/// `set` insert branch, as the format's declared `key_style` says —
/// see `Syntax.KeyStyle` for what each spelling is and why.
/// Always returns an owned slice (the caller frees it).
fn formatInsertKey(self: *Self, key: []const u8) ![]u8 {
switch (self.syntax().key_style) {
.json_quoted => {
var w = std.Io.Writer.Allocating.init(self.allocator);
defer w.deinit();
try json_string.writeQuoted(&w.writer, key);
return self.allocator.dupe(u8, w.written());
},
.zon_field => {
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
try zon_edit.appendFieldName(&out, self.allocator, key);
return out.toOwnedSlice(self.allocator);
},
.verbatim => return self.allocator.dupe(u8, key),
}
}
/// Like `replaceValAtPath`, but follow into the reference layer: when the
/// target value is an alias, edit the *anchored node* (the shared source),
/// so every alias to that anchor reflects the change. The `&name` (and any
/// tag) prefix is preserved — only the anchored value's bytes are
/// replaced. A non-alias target behaves exactly like `replaceValAtPath`.
///
/// **Hook** `replaceValAtPathFollowing(self, parsed, path, node, span,
/// replacement) !void`, same signature as `replaceValAtPath`'s. Declared
/// by YAML alone, because YAML alone HAS a reference layer: with no
/// hook, "following" and not following are the same operation, which is
/// exactly what the fall-through below expresses.
pub fn replaceValAtPathFollowing(self: *Self, path: []const AST.PathSegment, replacement: []const u8) !void {
const parsed = try self.getParsed();
const node = parsed.ast.getValByPath(path) catch {
return self.replaceValAtPath(path, replacement);
};
if (@hasDecl(Language, "replaceValAtPathFollowing"))
return Language.replaceValAtPathFollowing(self, parsed, path, node, parsed.span(node), replacement);
try self.replaceValAtPath(path, replacement);
}
/// Rename the key at `path`, leaving its value untouched.
///
/// **Hook** `replaceKeyAtPath(self, parsed, path, replacement) !void` —
/// replaces this op wholesale, before the key node is resolved, for a
/// format where a key's span is not the whole of its syntax. Declared by
/// NestedText: a plain key's span excludes its trailing `:` (so a
/// plain-to-plain rename splices directly, as below), but a MULTILINE
/// key (`: key\n: continued`) has no separator colon in the source at
/// all, so converting between the two forms means adding or dropping
/// one.
pub fn replaceKeyAtPath(self: *Self, path: []const AST.PathSegment, replacement: []const u8) !void {
const parsed = try self.getParsed();
if (@hasDecl(Language, "replaceKeyAtPath"))
return Language.replaceKeyAtPath(self, parsed, path, replacement);
const node = try parsed.ast.getKeyByPath(path);
const span = parsed.span(node);
try self.replaceAtSpan(span, replacement);
}
// ========
// COMMENTS
// ========
//
// Comments are trivia — they live OUTSIDE every AST node span — so these
// ops reuse the same splice + reparse machinery as the structural edits:
// compute a byte position from a node's span, splice the comment text,
// reparse. The reparse is the safety net (`replaceAtSpan` rolls back if
// the result no longer parses).
//
// **Hooks.** Each of the six ops below dispatches to a `Language`
// declaration of the same name when one exists, passing exactly its own
// arguments (`self, path` — plus `text` for the two setters) and handing
// over the operation entirely; the marker lookup and the whole generic
// body are skipped. plist declares all six, because a plist comment is a
// `<!-- ... -->` PAIR rather than a line carrying a marker, so none of
// the marker-scanning below has anything to scan for.
/// The line-comment marker for the dialect this document is being read
/// as, or null when that dialect forbids comments (strict JSON) — in
/// which case the comment ops return `CommentsUnsupported`. Indexed by
/// `self.format` because the splice is reparsed under that same
/// dialect. See `Comments.line`.
fn lineCommentMarker(self: *const Self) ?[]const u8 {
return self.syntax().comments.line;
}
/// The marker for a same-line TRAILING comment specifically, or null
/// for a format that has no such syntax (INI, NestedText — where a
/// `;`/`#` after a value is literal value text). Distinct from
/// `lineCommentMarker`, which those two formats do have. See
/// `Comments.trailing` for the full reasoning.
fn trailingCommentMarker(self: *const Self) ?[]const u8 {
return self.syntax().comments.trailing;
}
/// The key/value separator the GENERIC entry-insert helpers splice.
///
/// Every caller sits under the generic `insertKey`/`promoteNullToMapping`
/// dispatch, so a format that declares `kv_sep = null` — fig, TOML,
/// plist, NestedText — cannot reach one: `language.validate` requires a
/// null to come with an `insertKey` hook, and the hook replaces this
/// whole path. The error is the same "unreachable by construction"
/// answer `setSequence` gives on its own impossible branch, rather than
/// a fabricated separator that would splice syntax the format's own
/// parser rejects — fig's `": "` was exactly that.
fn kvSep(self: *const Self) ![]const u8 {
return self.syntax().kv_sep orelse error.UnsupportedShape;
}
/// Whether a comment op at `path` has no line of its own to work with:
/// the node is an element or entry of a flow collection that shares its
/// parent's line (`members = ["a", "b"]`, `members: [a, b]`,
/// `nested = { k = "v" }`).
///
/// Per § 3.4/§ 6.3 a comment written *inside* a flow collection is
/// discarded at parse, so such a node can never own a leading block or
/// a same-line trailing comment. Anchoring on the node's line anyway
/// made every comment op reach the PARENT's through the item: the read
/// returned the parent's block, `deleteLeadingComments` removed it, and
/// `addLeadingComment` inserted above the parent's line (on fig, whose
/// indent is the raw line prefix, it spliced the prefix `members = [`
/// back in as well). See
/// `docs/tasks/flow-item-leading-comment-is-the-parents.md`.
///
/// The test is what SHARES the line, not the node's column: the parent
/// is flow, and either the parent's opener (`key = [`) or a preceding
/// element sits on the node's own line. Asking instead whether the node
/// begins its line would be wrong for every format that decorates the
/// line before the node's span — ZON's `.` in `.n = 3`, a block
/// sequence's `- `, fig's `> ` marker run — and an item of a MULTI-LINE
/// flow collection (one element per line) has to keep working, since
/// each of those does own its line.
///
/// The document root is excluded: `isFlow`'s first-character test reads
/// a TOML file that opens with `[table]` as a flow root, and a root
/// entry has no parent key line for its comment to be confused with
/// anyway.
///
/// Infallible: an unresolvable path answers "anchored" so the caller's
/// own `getNodeByPath`/`getValByPath` raises the real `NotFound`.
fn commentsUnanchored(self: *const Self, parsed: Document, path: []const AST.PathSegment) bool {
if (path.len == 0) return false;
const source = self.source.items;
const parent = parsed.ast.getValByPath(path[0 .. path.len - 1]) catch return false;
if (parent.id == parsed.ast.root) return false;
const parent_span = parsed.span(parent);
if (!isFlow(source, parent_span)) return false;
const node = parsed.ast.getNodeByPath(path) catch return false;
const line = lineStartBefore(source, parsed.span(node).start);
// The opener is on this line, so what precedes the node is the
// parent's own `key = [` — the line, and the block above it, are
// the parent's.
if (lineStartBefore(source, parent_span.start) == line) return true;
// Otherwise the node is unanchored only if a preceding element ends
// on the same line (`[\n "a", "b",\n]` — "b" shares "a"'s line).
var prev_end: ?usize = null;
var cur = (parsed.ast.child(&parent) catch return false) orelse return false;
while (cur.id != node.id) {
prev_end = parsed.span(cur).end;
cur = parsed.ast.next(&cur) orelse return false;
}
const end = prev_end orelse return false;
return lineStartBefore(source, end -| 1) == line;
}
/// The line a leading-comment op anchors on: the node's own line start,
/// which for a mapping entry is its key's line.
///
/// **Hook** `seqItemLineStart(source, parsed, path) !usize` — consulted
/// only when `path`'s final segment is an `.index`. Declared by
/// NestedText alone: its sequence items carry no keyvalue-shaped
/// wrapper node, so a nested or empty item's value span can begin on a
/// LATER line than the item's own `-` dash, and a comment anchored on
/// `span.start`'s line would land inside the item rather than above it.
/// Every other block format keeps some token on the dash's own line, so
/// `lineStartBefore` is already the dash's line there.
fn leadingCommentLineStart(self: *const Self, parsed: Document, path: []const AST.PathSegment, span: Span) !usize {
const source = self.source.items;
if (@hasDecl(Language, "seqItemLineStart") and path.len > 0 and std.meta.activeTag(path[path.len - 1]) == .index)
return Language.seqItemLineStart(source, parsed, path);
return lineStartBefore(source, span.start);
}
/// Add an own-line comment ABOVE the node at `path` — the key's line for a
/// mapping entry, else the node's own line — matched to that line's
/// indentation. It lands at the BOTTOM of any existing leading comment
/// block (the comment line nearest the node). `text` may be multi-line;
/// each line becomes its own comment line. Returns `CommentsUnsupported`
/// for a dialect without comment syntax (strict JSON), and
/// `CommentsUnanchored` for a node that shares its parent's line inside
/// a flow collection (see `commentsUnanchored`) — there is no line to
/// put a comment on that the node would own.
pub fn addLeadingComment(self: *Self, path: []const AST.PathSegment, text: []const u8) !void {
if (@hasDecl(Language, "addLeadingComment")) return Language.addLeadingComment(self, path, text);
const marker = self.lineCommentMarker() orelse return error.CommentsUnsupported;
const parsed = try self.getParsed();
if (self.commentsUnanchored(parsed, path)) return error.CommentsUnanchored;
const node = try parsed.ast.getNodeByPath(path);
const span = parsed.span(node);
const source = self.source.items;
const line_start = try self.leadingCommentLineStart(parsed, path, span);
// A format whose line prefix is STRUCTURAL (fig's `>` marker run)
// copies the raw prefix; everywhere else it is pure whitespace.
// See `Syntax.structural_indent`.
const indent = if (self.syntax().structural_indent)
source[line_start..span.start]
else
source[line_start..firstNonSpace(source, line_start)];
var buf: std.ArrayList(u8) = .empty;
defer buf.deinit(self.allocator);
try renderLineComments(self.allocator, &buf, indent, marker, text);
try self.replaceAtSpan(Span.init(line_start, line_start), buf.items);
}
/// The byte window `[start, line_end)` on the entry-at-`path`'s line where a
/// same-line trailing comment lives, shared by the set/delete/get trailing
/// ops. For a scalar or flow value the window runs from just past the value
/// to that line's newline. For a BLOCK-style mapping/sequence value — whose
/// node span begins at its first child on a later line — the trailing
/// comment instead rides the key's line (e.g. `contents: # note` above a
/// block sequence), so the window is the key line, starting just past the
/// key. `start` always sits before any comment marker and after the value
/// (scalar) or key (block), so a `#`/`//` inside the value can't false-match.
///
/// `null` when the node has no such window at all: a flow element or
/// entry sharing its parent's line, whose line-end comment is the
/// PARENT's (see `commentsUnanchored`). Each caller turns that into its
/// own "as if there were none" answer.
fn trailingCommentWindow(self: *Self, path: []const AST.PathSegment) !?struct { start: usize, line_end: usize } {
const parsed = try self.getParsed();
if (self.commentsUnanchored(parsed, path)) return null;
const val = try parsed.ast.getValByPath(path);
const val_span = parsed.span(val);
const source = self.source.items;
const is_block_collection = switch (std.meta.activeTag(val.kind)) {
.mapping, .sequence => !isFlow(source, val_span),
else => false,
};
const start = if (is_block_collection)
parsed.span(try parsed.ast.getKeyByPath(path)).end
else
val_span.end;
const line_end = std.mem.indexOfScalarPos(u8, source, start, '\n') orelse source.len;
return .{ .start = start, .line_end = line_end };
}
/// Set the same-line trailing comment on the value at `path`: replace an
/// existing trailing comment on that line, or append one if there is none.
/// `text` must be a single line. Returns `CommentsUnsupported` for a
/// dialect without comment syntax (strict JSON), `MultilineComment` if
/// `text` contains a newline, and `CommentsUnanchored` for a node that
/// shares its parent's line inside a flow collection (see
/// `commentsUnanchored`) — the end of that line is the parent's.
pub fn setTrailingComment(self: *Self, path: []const AST.PathSegment, text: []const u8) !void {
if (@hasDecl(Language, "setTrailingComment")) return Language.setTrailingComment(self, path, text);
const marker = self.trailingCommentMarker() orelse return error.CommentsUnsupported;
if (std.mem.indexOfScalar(u8, text, '\n') != null) return error.MultilineComment;
const win = try self.trailingCommentWindow(path) orelse return error.CommentsUnanchored;
const source = self.source.items;
// If a comment marker already follows on this line, splice from it
// (replace); otherwise splice from the line's end (append).
var cut = if (std.mem.indexOf(u8, source[win.start..win.line_end], marker)) |rel|
win.start + rel
else
win.line_end;
// Drop the run of spaces/tabs just before the splice so the rebuilt
// " <marker> text" controls its own single leading space.
while (cut > win.start and (source[cut - 1] == ' ' or source[cut - 1] == '\t')) cut -= 1;
var buf: std.ArrayList(u8) = .empty;
defer buf.deinit(self.allocator);
try buf.appendSlice(self.allocator, " ");
try buf.appendSlice(self.allocator, marker);
if (text.len > 0) {
try buf.append(self.allocator, ' ');
try buf.appendSlice(self.allocator, text);
}
try self.replaceAtSpan(Span.init(cut, win.line_end), buf.items);
}
/// Remove the run of own-line comments immediately ABOVE the node at
/// `path` — its owned leading block (contiguous comment lines with no
/// blank line between, the same block `deleteKey` carries). A no-op when
/// the node has none — including a node that shares its parent's line
/// inside a flow collection, whose block above is the parent's (see
/// `commentsUnanchored`). Returns `CommentsUnsupported` for a dialect
/// without comment syntax (strict JSON).
pub fn deleteLeadingComments(self: *Self, path: []const AST.PathSegment) !void {
if (@hasDecl(Language, "deleteLeadingComments")) return Language.deleteLeadingComments(self, path);
_ = self.lineCommentMarker() orelse return error.CommentsUnsupported;
const parsed = try self.getParsed();
// Not the node's block to remove (the path resolved: an
// unresolvable one answers "anchored" and falls through to the
// `getNodeByPath` below, which raises `NotFound`).
if (self.commentsUnanchored(parsed, path)) return;
const node = try parsed.ast.getNodeByPath(path);
const span = parsed.span(node);
const source = self.source.items;
const line_start = try self.leadingCommentLineStart(parsed, path, span);
const block_start = commentBlockStart(source, line_start, self.syntax().comments.style);
if (block_start == line_start) return; // nothing above to remove
try self.replaceAtSpan(Span.init(block_start, line_start), "");
}
/// Remove the same-line trailing comment on the value at `path`, if any.
/// A no-op when there is none — including a node that shares its
/// parent's line inside a flow collection, whose line-end comment is the
/// parent's (see `commentsUnanchored`). Returns `CommentsUnsupported`
/// for a dialect without comment syntax (strict JSON).
pub fn deleteTrailingComment(self: *Self, path: []const AST.PathSegment) !void {
if (@hasDecl(Language, "deleteTrailingComment")) return Language.deleteTrailingComment(self, path);
const marker = self.trailingCommentMarker() orelse return error.CommentsUnsupported;
const win = try self.trailingCommentWindow(path) orelse return; // not this node's line-end
const source = self.source.items;
const rel = std.mem.indexOf(u8, source[win.start..win.line_end], marker) orelse return; // none
var cut = win.start + rel;
// Take the whitespace separating the value from the comment with it.
while (cut > win.start and (source[cut - 1] == ' ' or source[cut - 1] == '\t')) cut -= 1;
try self.replaceAtSpan(Span.init(cut, win.line_end), "");
}
/// Read back the own-line comment block immediately ABOVE the node at
/// `path` — the same owned block `deleteLeadingComments` removes — with each
/// line's indentation and `marker` (and one following space) stripped, lines
/// rejoined by '\n'. Returns `null` when there is no block above the node
/// (distinct from a present-but-empty comment — a bare `#` — which yields
/// ""), which includes a node that shares its parent's line inside a flow
/// collection: the block above that line is the parent's, not the node's
/// (see `commentsUnanchored`). The caller owns the returned bytes. Returns
/// `CommentsUnsupported` for a dialect without comment syntax (strict JSON).
pub fn getLeadingComment(self: *Self, path: []const AST.PathSegment) !?[]u8 {
if (@hasDecl(Language, "getLeadingComment")) return Language.getLeadingComment(self, path);
const marker = self.lineCommentMarker() orelse return error.CommentsUnsupported;
const parsed = try self.getParsed();
if (self.commentsUnanchored(parsed, path)) return null;
const node = try parsed.ast.getNodeByPath(path);
const span = parsed.span(node);
const source = self.source.items;
const line_start = try self.leadingCommentLineStart(parsed, path, span);
const block_start = commentBlockStart(source, line_start, self.syntax().comments.style);
if (block_start == line_start) return null; // no block above
var out: std.ArrayList(u8) = .empty;
errdefer out.deinit(self.allocator);
var it = std.mem.splitScalar(u8, source[block_start..line_start], '\n');
var first = true;
while (it.next()) |raw| {
const line = std.mem.trimEnd(u8, raw, "\r");
const trimmed = std.mem.trimStart(u8, line, " \t");
if (trimmed.len == 0) continue; // skip a trailing empty split slice
if (!first) try out.append(self.allocator, '\n');
first = false;
try out.appendSlice(self.allocator, stripLineCommentMarker(trimmed, marker));
}
return try out.toOwnedSlice(self.allocator);
}
/// Read back the same-line trailing comment on the value at `path` — the
/// one `setTrailingComment` sets and `deleteTrailingComment` removes — with
/// its `marker` (and one following space) stripped. Returns `null` when
/// there is no trailing comment (distinct from a present-but-empty bare `#`,
/// which yields ""), which includes a node that shares its parent's line
/// inside a flow collection: the comment at that line's end is the parent's
/// (see `commentsUnanchored`). The caller owns the returned bytes. Returns
/// `CommentsUnsupported` for a dialect without comment syntax (strict JSON).
pub fn getTrailingComment(self: *Self, path: []const AST.PathSegment) !?[]u8 {
if (@hasDecl(Language, "getTrailingComment")) return Language.getTrailingComment(self, path);
const marker = self.trailingCommentMarker() orelse return error.CommentsUnsupported;
const win = try self.trailingCommentWindow(path) orelse return null;
const source = self.source.items;
const rel = std.mem.indexOf(u8, source[win.start..win.line_end], marker) orelse
return null; // none
const after = std.mem.trimEnd(u8, source[win.start + rel .. win.line_end], " \t\r");
return try self.allocator.dupe(u8, stripLineCommentMarker(after, marker));
}
// ── The dangling anchor ─────────────────────────────────────────────
//
// A container's THIRD comment anchor (spec § 3.4): the run of own-line
// comments at the END of its body, after its last entry, which the AST
// side-table carries as `NodeComments.dangling` and every printer
// emits. The leading trio addresses a comment by the node it sits
// above; nothing addressed this one, because it sits above nothing —
// and a commented-out LAST entry is exactly a dangling run.
//
// Where the run is, in source: from just past the last line of the
// container's body, forward over each contiguous own-line comment
// whose line carries at least the body's child indent. That is spec
// § 3.4's own rule — "a comment at or deeper than the closing
// container's child depth becomes that container's dangling run; a
// shallower one stays pending as a leading comment on the next
// sibling" — read off the source rather than the parse, which is what
// makes it the exact inverse of what `addDanglingComment` writes.
//
// One ambiguity is inherent and shared with the leading trio: a
// comment line at child depth with an entry directly below it is both
// this container's dangling run and that entry's leading block, and
// both ops report it. `commentBlockStart` has always worked that way;
// resolving it would need the parse's attribution, and the parse
// discards where a comment came from.
/// Where a container's dangling run lives: the offset it starts at
/// (just past the container body's last line) and the line prefix its
/// lines carry (the body's child depth).
const DanglingAnchor = struct { at: usize, indent: []const u8 };
/// Resolve the dangling anchor of the container at `path` (the root for
/// an empty path). `UnsupportedShape` for a scalar — a dangling run is
/// a container's — and for a flow container with no room for an
/// own-line comment: one written on a single line (`{ "a": 1 }`, where
/// the run would have to break it) or with no children at all.
///
/// A flow container that DOES span lines is fine and is the shape this
/// matters for: a pretty-printed JSONC object's `// note` before the
/// closing brace is the root's dangling run, and nothing else can
/// address it. (fig discards its own flow collections' interior
/// comments at parse, spec § 6.3 — the bytes still land, but the tree
/// will not carry them. The comment-out pair refuses flow outright,
/// where a marker would swallow a separator.)
///
/// The body ends after the last child written on the container's OWN
/// lines. A child that is itself a SECTION is skipped: its lines are
/// assembled from elsewhere in the file, and the run belongs before the
/// sub-tables, not after them — the same place `toml/printer.zig` emits
/// it. A block container with no such child (an empty `[table]`)
/// anchors just past its header line(s).
fn danglingAnchor(self: *const Self, parsed: Document, path: []const AST.PathSegment) !DanglingAnchor {
const node = try parsed.ast.getValByPath(path);
switch (node.kind) {
.mapping, .sequence => {},
else => return error.UnsupportedShape,
}
const source = self.source.items;
const span = parsed.span(node);
const flow = isFlow(source, span);
const structural = self.syntax().structural_indent;
var last: ?AST.Node = null;
var maybe = try parsed.ast.child(&node);
while (maybe) |c| {
const val = if (c.kind == .keyvalue) parsed.ast.nodes[c.kind.keyvalue.value] else c;
if (!parsed.isSection(val)) last = c;
maybe = parsed.ast.next(&c);
}
if (last) |c| {
const c_span = parsed.span(c);
const line_start = lineStartBefore(source, c_span.start);
const at = lineEndAfter(source, c_span.end -| 1);
// A flow container whose closing delimiter shares the last
// child's line has no line for a run to sit on, and `at` is
// already past the container.
if (flow and at >= span.end) return error.UnsupportedShape;
return .{
.at = at,
.indent = source[line_start..commentColumn(source, line_start, structural)],
};
}
// Nothing on its own lines. A flow container has no body line to
// anchor on at all; a section container still has its
// header line(s) recorded; anything else falls back to its own
// line, which for a childless block container is where its body
// would begin. The indent is that line's, which is a level short
// for a format whose depth is structural (fig): an empty
// container is the one shape where the child depth cannot be read
// off a child, and a format that needs better hooks these ops.
if (flow) return error.UnsupportedShape; // `{}` — no body to end
const regs = parsed.regionsOf(node.id);
const anchor_at = if (regs.len > 0) regs[regs.len - 1].end else lineEndAfter(source, span.end -| 1);
const own_line = lineStartBefore(source, if (regs.len > 0) regs[regs.len - 1].start else span.start);
return .{
.at = anchor_at,
.indent = source[own_line..commentColumn(source, own_line, structural)],
};
}
/// Byte offset just past the dangling run starting at `anchor.at`: the
/// contiguous own-line `marker` comments carrying at least
/// `anchor.indent`. Stops at a blank line, at content, at a dedent, and
/// at end of input. Equal to `anchor.at` when there is no run.
fn danglingRunEnd(self: *const Self, anchor: DanglingAnchor, marker: []const u8) usize {
const source = self.source.items;
const structural = self.syntax().structural_indent;
var pos = anchor.at;
while (pos < source.len) {
const line_end = lineEndAfter(source, pos);
if (!std.mem.startsWith(u8, source[pos..line_end], anchor.indent)) break;
const col = commentColumn(source, pos, structural);
if (!std.mem.startsWith(u8, source[col..line_end], marker)) break;
pos = line_end;
}
return pos;
}
/// Read back the dangling comment run at the end of the container at
/// `path`'s body (the root for an empty path) — the third anchor beside
/// `getLeadingComment`/`getTrailingComment` — with each line's prefix
/// and `marker` (and one following space) stripped, lines rejoined by
/// '\n'. `null` when there is no run (distinct from a bare marker,
/// which yields ""). The caller owns the returned bytes.
/// `CommentsUnsupported` for a dialect without comment syntax (strict
/// JSON); `UnsupportedShape` for a scalar, or a flow container with no
/// line for a run to sit on (see `danglingAnchor`).
///
/// **Hook** `getDanglingComment(self, path) !?[]u8`, as for the leading
/// trio. A format whose comment syntax has no line marker (plist's
/// `<!-- -->`) answers `CommentsUnsupported` until it declares one.
pub fn getDanglingComment(self: *Self, path: []const AST.PathSegment) !?[]u8 {
if (@hasDecl(Language, "getDanglingComment")) return Language.getDanglingComment(self, path);
const marker = self.lineCommentMarker() orelse return error.CommentsUnsupported;
const parsed = try self.getParsed();
const anchor = try self.danglingAnchor(parsed, path);
const end = self.danglingRunEnd(anchor, marker);
if (end == anchor.at) return null;
const source = self.source.items;
const structural = self.syntax().structural_indent;
var out: std.ArrayList(u8) = .empty;
errdefer out.deinit(self.allocator);
var pos = anchor.at;
var first = true;
while (pos < end) {
const line_end = lineEndAfter(source, pos);
const body = std.mem.trimEnd(u8, source[commentColumn(source, pos, structural)..line_end], "\r\n");
if (!first) try out.append(self.allocator, '\n');
first = false;
try out.appendSlice(self.allocator, stripLineCommentMarker(body, marker));
pos = line_end;
}
return try out.toOwnedSlice(self.allocator);
}
/// Add own-line comment line(s) at the END of the container at `path`'s
/// body, at the body's child depth — the dangling twin of
/// `addLeadingComment`, landing at the bottom of any run already there.
/// `text` may be multi-line; each line becomes its own comment line.
/// `CommentsUnsupported` for a dialect without comment syntax (strict
/// JSON); `UnsupportedShape` for a scalar, or a flow container with no
/// line for a run to sit on (see `danglingAnchor`).
///
/// **Hook** `addDanglingComment(self, path, text) !void`.
pub fn addDanglingComment(self: *Self, path: []const AST.PathSegment, text: []const u8) !void {
if (@hasDecl(Language, "addDanglingComment")) return Language.addDanglingComment(self, path, text);
const marker = self.lineCommentMarker() orelse return error.CommentsUnsupported;
const parsed = try self.getParsed();
const anchor = try self.danglingAnchor(parsed, path);
const at = self.danglingRunEnd(anchor, marker);
var buf: std.ArrayList(u8) = .empty;
defer buf.deinit(self.allocator);
// A final line with no newline of its own would otherwise weld the
// first comment onto it.
if (at > 0 and self.source.items[at - 1] != '\n') try buf.append(self.allocator, '\n');
try renderLineComments(self.allocator, &buf, anchor.indent, marker, text);
try self.replaceAtSpan(Span.init(at, at), buf.items);
}
/// Remove the whole dangling run at the end of the container at
/// `path`'s body. A no-op when there is none. `CommentsUnsupported` for
/// a dialect without comment syntax (strict JSON); `UnsupportedShape`
/// for a scalar, or a flow container with no line for a run to sit on.
///
/// **Hook** `deleteDanglingComments(self, path) !void`.
pub fn deleteDanglingComments(self: *Self, path: []const AST.PathSegment) !void {
if (@hasDecl(Language, "deleteDanglingComments")) return Language.deleteDanglingComments(self, path);
const marker = self.lineCommentMarker() orelse return error.CommentsUnsupported;
const parsed = try self.getParsed();
const anchor = try self.danglingAnchor(parsed, path);
const end = self.danglingRunEnd(anchor, marker);
if (end == anchor.at) return;
try self.replaceAtSpan(Span.init(anchor.at, end), "");
}
// ── Comment out, and back ───────────────────────────────────────────
//
// A commented-out entry — `# port = 8080` under a `[server]` — is what
// a structural editor shows as a DISABLED row with a toggle. Both
// directions are one splice over the node's own span: re-serializing
// the value and calling `addLeadingComment` would lose the entry's
// spelling (its quoting, its layout, the comments inside it), and
// stripping the markers and calling `insertValue` would lose the same
// going the other way.
/// Whether the node at `span`, whose own line begins at `line_start`,
/// has those lines TO ITSELF — the precondition both halves of the
/// comment-out pair rest on, since a line marker hides everything after
/// it to end of line.
///
/// Before the node, only indentation and the format's own line
/// introducers may stand (a `- `/`* ` item dash, a fig `>` marker run,
/// a `+` continuation). After it, only whitespace, one separating
/// comma, and a trailing comment. Anything else means a SIBLING shares
/// the line — the entries of `{ "a": 1, "b": 2 }`, the items of
/// `[a, b]` — or that a closing delimiter does, and commenting the line
/// out would take that with it.
///
/// Stated as line ownership rather than as "is the parent a flow
/// container", because those are not the same question: a
/// pretty-printed JSONC object is flow-spelled and one entry per line,
/// and commenting one of its members out is exactly what a JSONC editor
/// wants; a one-line YAML flow sequence is the shape that cannot.
fn ownsItsLines(self: *const Self, line_start: usize, span: Span, marker: []const u8) bool {
const source = self.source.items;
for (source[line_start..span.start]) |c| switch (c) {
' ', '\t', '-', '*', '>', '+' => {},
else => return false,
};
const line_end = lineEndAfter(source, span.end -| 1);
var i = span.end;
var comma = false;
while (i < line_end) : (i += 1) {
switch (source[i]) {
' ', '\t', '\r', '\n' => {},
',' => {
if (comma) return false;
comma = true;
},
else => return std.mem.startsWith(u8, source[i..line_end], marker),
}
}
return true;
}
/// Turn the node at `path` into a comment run: every line of its source
/// span — the key through the end of its value for a mapping entry, the
/// item for a sequence item — gains the line marker at that line's own
/// indentation (past a structural prefix, so a nested fig line keeps
/// its depth). The node's own leading comment block stays above it,
/// untouched, so a `# why` above a commented-out entry survives as a
/// note on the note.
///
/// Afterwards the tree no longer has the node: the run is the leading
/// block of what followed it, or — when it was last — the parent's
/// dangling run, which `uncommentLeading`/`uncommentDangling` address
/// to bring it back.
///
/// `CommentsUnsupported` for a dialect without comment syntax (strict
/// JSON). `UnsupportedShape` for the root (an empty path);
/// `CommentsUnanchored` — the answer the six comment ops give the same
/// node — for one that does not have its lines to itself: an item of a
/// one-line flow collection (`tags = [a, b]`), where the marker would
/// swallow a separator and where fig discards an interior comment at
/// parse anyway (spec § 6.3). See `ownsItsLines`. A node whose value is a
/// SECTION is refused with the format's own vocabulary
/// (`CannotDeleteTable` / `CannotDeleteSection` /
/// `CannotDeleteContainer`) for the reason `deleteKey` refuses it: its
/// span is a name inside a header, and its body is lines this op cannot
/// see.
///
/// **Hook** `commentOut(self, path) !void`.
pub fn commentOut(self: *Self, path: []const AST.PathSegment) !void {
if (@hasDecl(Language, "commentOut")) return Language.commentOut(self, path);
const marker = self.lineCommentMarker() orelse return error.CommentsUnsupported;
if (path.len == 0) return error.UnsupportedShape;
const parsed = try self.getParsed();
const node = try parsed.ast.getNodeByPath(path);
const source = self.source.items;
const val = if (node.kind == .keyvalue) parsed.ast.nodes[node.kind.keyvalue.value] else node;
if (parsed.isSection(val)) return self.refuse(.delete);
const span = parsed.span(node);
const start = try self.leadingCommentLineStart(parsed, path, span);
const end = lineEndAfter(source, span.end -| 1);
if (!self.ownsItsLines(start, span, marker)) return error.CommentsUnanchored;
const structural = self.syntax().structural_indent;
var buf: std.ArrayList(u8) = .empty;
defer buf.deinit(self.allocator);
var pos = start;
while (pos < end) {
const line_end = lineEndAfter(source, pos);
const col = commentColumn(source, pos, structural);
try buf.appendSlice(self.allocator, source[pos..col]);
try buf.appendSlice(self.allocator, marker);
// No trailing space on an otherwise empty line — the same rule
// `renderLineComments` follows, and what keeps the round trip
// byte-exact through a blank line inside a block scalar.
const rest = source[col..line_end];
if (rest.len > 0 and rest[0] != '\n' and rest[0] != '\r') try buf.append(self.allocator, ' ');
try buf.appendSlice(self.allocator, rest);
pos = line_end;
}
try self.replaceAtSpan(Span.init(start, end), buf.items);
}
/// Bring `line_count` lines of the LEADING comment block above the node
/// at `path`, starting at `first_line` (0-based within that block),
/// back as entries: strip the marker and one following space from each,
/// then reparse.
///
/// Lines are addressed by index rather than matched by content because
/// WHICH lines look like an entry is the caller's judgement — it parses
/// the block as a fragment and decides. The editor's part is the byte
/// edit and the guarantee that it landed: if the result does not parse,
/// or parses to a document whose other nodes changed, the splice is
/// rolled back and the call fails (the parse error, or
/// `CommentNotAnEntry`) with the document byte-for-byte as it was.
///
/// The block is exactly the one `getLeadingComment` reports — the same
/// `commentBlockStart` scan — so a caller can read the block, decide
/// which of its lines are an entry, and name them by the index it read
/// them at. (That scan does not climb past a structural prefix, so a
/// fig comment line carrying a `>` marker run is not part of any node's
/// leading block for either op. A commented-out nested fig entry is the
/// container's dangling run when it was last, which
/// `uncommentDangling` does address.)
///
/// `NotFound` when the block has fewer than `first_line + line_count`
/// lines; a `line_count` of 0 is a no-op. `CommentsUnsupported` for a
/// dialect without comment syntax (strict JSON); `UnsupportedShape` for
/// the root, and `CommentsUnanchored` for a node that does not own its
/// lines (`ownsItsLines`), as the six comment ops answer it.
///
/// **Hook** `uncommentLeading(self, path, first_line, line_count) !void`.
pub fn uncommentLeading(self: *Self, path: []const AST.PathSegment, first_line: usize, line_count: usize) !void {
if (@hasDecl(Language, "uncommentLeading"))
return Language.uncommentLeading(self, path, first_line, line_count);
const marker = self.lineCommentMarker() orelse return error.CommentsUnsupported;
if (path.len == 0) return error.UnsupportedShape;
const parsed = try self.getParsed();
const node = try parsed.ast.getNodeByPath(path);
const source = self.source.items;
const parent_path = path[0 .. path.len - 1];
const span = parsed.span(node);
const line_start = try self.leadingCommentLineStart(parsed, path, span);
if (!self.ownsItsLines(line_start, span, marker)) return error.CommentsUnanchored;
const block_start = commentBlockStart(source, line_start, self.syntax().comments.style);
return self.uncommentBlock(block_start, line_start, first_line, line_count, parent_path);
}
/// The dangling twin of `uncommentLeading`: bring `line_count` lines of
/// the DANGLING run at the end of the container at `container_path`'s
/// body, starting at `first_line`, back as entries of that container.
/// The op that re-enables a commented-out LAST entry, which has no
/// following sibling to be the leading block of.
///
/// Same guarantee, same errors — see `uncommentLeading`.
///
/// **Hook** `uncommentDangling(self, container_path, first_line,
/// line_count) !void`.
pub fn uncommentDangling(self: *Self, container_path: []const AST.PathSegment, first_line: usize, line_count: usize) !void {
if (@hasDecl(Language, "uncommentDangling"))
return Language.uncommentDangling(self, container_path, first_line, line_count);
const marker = self.lineCommentMarker() orelse return error.CommentsUnsupported;
const parsed = try self.getParsed();
const anchor = try self.danglingAnchor(parsed, container_path);
const end = self.danglingRunEnd(anchor, marker);
return self.uncommentBlock(anchor.at, end, first_line, line_count, container_path);
}
/// The shared body of the two uncomment ops: strip the marker (and one
/// following space) from lines `[first_line, first_line + line_count)`
/// of the comment block `[block_start, block_end)`, splice the whole
/// block back in one edit, and keep the result only if it parses AND
/// adds nodes to nothing but the container at `container_path`.
///
/// The marker is looked for where `commentOut` writes it
/// (`commentColumn`), so a line that is not a comment at all — or one
/// whose marker sits somewhere else entirely — is `CommentNotAnEntry`
/// before anything is spliced.
fn uncommentBlock(
self: *Self,
block_start: usize,
block_end: usize,
first_line: usize,
line_count: usize,
container_path: []const AST.PathSegment,
) !void {
if (line_count == 0) return;
const marker = self.lineCommentMarker() orelse return error.CommentsUnsupported;
const structural = self.syntax().structural_indent;
const source = self.source.items;
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
var pos = block_start;
var index: usize = 0;
var stripped: usize = 0;
while (pos < block_end) {
const line_end = @min(lineEndAfter(source, pos), block_end);
if (index >= first_line and index < first_line + line_count) {
const col = commentColumn(source, pos, structural);
if (!std.mem.startsWith(u8, source[col..line_end], marker)) return error.CommentNotAnEntry;
try out.appendSlice(self.allocator, source[pos..col]);
var rest = source[col + marker.len .. line_end];
if (rest.len > 0 and rest[0] == ' ') rest = rest[1..];
try out.appendSlice(self.allocator, rest);
stripped += 1;
} else {
try out.appendSlice(self.allocator, source[pos..line_end]);
}
index += 1;
pos = line_end;
}
if (stripped != line_count) return error.NotFound; // fewer lines than asked for
// Snapshot before the splice: the check below compares the parse of
// these bytes against the parse of the edited ones, and a rollback
// has to be byte-exact, not a re-render.
const backup = try self.allocator.dupe(u8, self.source.items);
defer self.allocator.free(backup);
// A splice that doesn't parse rolls itself back (`replaceAtSpan`).
try self.replaceAtSpan(Span.init(block_start, block_end), out.items);
var parser: Language.Parser = .{ .allocator = self.allocator };
const before = Language.parse(&parser, backup, self.format) catch {
// `backup` parsed at `init` and every edit since kept it
// parsing, so this cannot happen; take the refusal rather than
// commit an edit nothing checked.
try self.restoreSource(backup);
return error.CommentNotAnEntry;
};
defer before.deinit(self.allocator);
if (!addedOnlyAt(before, try self.getParsed(), container_path)) {
try self.restoreSource(backup);
return error.CommentNotAnEntry;
}
}
// ===============
// INSERT / DELETE
// ===============
//
// These ops never reserialize the document: each computes a byte span +
// replacement text and reuses `replaceAtSpan` (splice + reparse). Inserts
// splice at a zero-length span; deletes splice an empty replacement.
// `value_text`/`key_text` arrive already serialized (single-line scalars,
// or multi-line block text indented from column 0); the editor only
// re-frames indentation and newline/comma context for the splice site.
/// Insert `key_text: value_text` into the mapping at `path` (empty path =
/// root). Appends after the mapping's last entry for block mappings, or
/// inside the braces for flow `{}`. If `path` resolves to a `null` value
/// (a bare `key:`), promotes it to a one-entry nested mapping.
///
/// **Hook** `insertKey(self, parsed, path, node, span, key_text,
/// value_text) !void` — replaces this op wholesale: `node` is already
/// resolved from `path` and `span` is its extent, and the hook owns
/// everything below, including the flow/block decision. Declared by
/// TOML, fig, INI, plist and NestedText.
pub fn insertKey(self: *Self, path: []const AST.PathSegment, key_text: []const u8, value_text: []const u8) !void {
const parsed = try self.getParsed();
const node = try parsed.ast.getValByPath(path);
const span = parsed.span(node);
const source = self.source.items;
if (@hasDecl(Language, "insertKey"))
return Language.insertKey(self, parsed, path, node, span, key_text, value_text);
switch (node.kind) {
.mapping => |first| {
if (isFlow(source, span)) {
try self.insertFlowMapEntry(parsed, node, span, first != null, key_text, value_text);
} else {
try self.insertBlockKey(parsed, node, key_text, value_text);
}
},
.null_ => try self.promoteNullToMapping(span, node.id == parsed.ast.root, key_text, value_text),
else => return error.NotAMapping,
}
}
/// Delete the mapping entry at `path` (which must name a key). For a
/// *block* mapping, removes the entry's full line(s) plus any owned
/// leading comment block (a run of comment lines — `#` for YAML/TOML,
/// `//` or `/* */` for JSON5/JSONC — with no intervening blank line),
/// leaving no blank gap. For a *flow* (`{…}`) mapping — any JSON/JSON5/
/// JSONC object, or a YAML/TOML/fig/ZON inline mapping — routes through a
/// comma-aware entry splice instead (see the comment at that branch),
/// since a flow mapping's entries are comma-separated rather than
/// one-per-line and the block path's line delete cannot handle them
/// safely at any arity or position.
pub fn deleteKey(self: *Self, path: []const AST.PathSegment) !void {
const parsed = try self.getParsed();
const node = parsed.ast.getNodeByPath(path) catch |err| {
// A key with no physical entry of its own — inherited through
// the format's reference layer — has no line to delete, and
// there is no syntax to un-inherit it; deleting the source it
// comes from is a different operation. Refuse explicitly rather
// than report it missing.
if (err == error.NotFound and try keyIsInherited(parsed, path))
return error.MergeOnlyKey;
return err;
};
if (node.kind != .keyvalue) return error.NotAMapping;
const span = parsed.span(node);
const source = self.source.items;
// The engine's veto, before anything is spliced: an entry whose
// value is a SECTION node, assembled from lines elsewhere in the
// file, so the line-based delete below would remove only the piece
// it can see and orphan or misparse the rest. `deleteContainer`
// is the op for it. See "Whole-container structural editing".
if (parsed.isSection(parsed.ast.nodes[node.kind.keyvalue.value])) return self.refuse(.delete);
// A flow (`{...}`) mapping stores its entries comma-separated, not
// one-per-line, so the line-based delete below (sized for a *block*
// mapping's one-entry-per-line shape) mishandles it in three ways:
// * packed `{ a: 1, b: 2 }` (the only shape JSON/JSON5/JSONC
// objects ever have, and one inline YAML/TOML/fig/ZON mappings
// also allow) — deleting the whole line swallows the sibling;
// * the *last* entry of a one-per-line flow mapping — the line
// delete strands the predecessor's separator comma before the
// closing `}`, invalid in strict JSON and in TOML inline tables;
// * a *single-entry* flow mapping — the line delete removes the
// whole `{ … }` down to nothing, which YAML/TOML/fig (whose
// grammar reads an empty document as an empty mapping) then
// silently "succeed" at reparsing, committing a wiped file to
// disk.
// So route every flow-mapping entry through `removeFlowItem` — the
// same comma-aware splice a flow *sequence* delete uses — which
// drops exactly one adjoining separator (the following comma for the
// first entry, the preceding comma otherwise) and always leaves the
// enclosing braces intact, correct for every arity and position.
const parent = try parsed.ast.getValByPath(path[0 .. path.len - 1]);
if (parent.kind == .mapping and isFlow(source, parsed.span(parent))) {
// Find the entry's immediate predecessor: `removeFlowItem` drops
// the *following* comma for the first entry and the *preceding*
// comma for any later one, so it needs to know which this is.
var item = (try parsed.ast.child(&parent)).?;
var prev: ?AST.Node = null;
while (item.id != node.id) {
prev = item;
item = parsed.ast.next(&item) orelse return error.NotFound;
}
// A key span that EXCLUDES the format's key sigil — ZON's
// leading `.`, whose span starts at the bare identifier (see
// `insertFlowMapEntry`'s doc on the same quirk) — is backed up
// over so the splice carries `.name` as a unit rather than
// stranding a bare `.` next to a survivor.
const entry_start = if (self.syntax().key_sigil) |sigil|
if (span.start > 0 and source[span.start - 1] == sigil) span.start - 1 else span.start
else
span.start;
// When the entry begins its own physical line, absorb any owned
// leading comment block above it — trivia `removeFlowItem` can't
// find on its own but the block path would have carried. A packed
// entry (a sibling or the opening brace shares its line) is not
// first-on-line, so this is skipped and `removeFlowItem`'s own
// whitespace scan handles the separator and indentation. The
// comment extension applies only when a block was actually found
// (`cbs` climbed above `line_start`); with none, splicing from
// the entry itself keeps the survivors' indentation intact.
const line_start = lineStartBefore(source, entry_start);
const on_own_line = firstNonSpace(source, line_start) == entry_start;
const cbs = if (on_own_line) commentBlockStart(source, line_start, self.syntax().comments.style) else line_start;
const del_start = if (cbs < line_start) cbs else entry_start;
return self.removeFlowItem(Span.init(del_start, span.end), prev == null);
}
const line_start = lineStartBefore(source, span.start);
const del_start = commentBlockStart(source, line_start, self.syntax().comments.style);
const del_end = lineEndAfter(source, span.end -| 1);
try self.replaceAtSpan(Span.init(del_start, del_end), "");
}
/// Append `value_text` as a new item to the sequence at `path`.
///
/// **Hook** `appendToSeq(self, parsed, node, value_text) !void` — takes
/// over the BLOCK arm only. A flow (`[…]`) sequence is comma-delimited
/// the same way in every format that has one, so it keeps the generic
/// path, and a format whose block sequences aren't editable at all
/// (`block_seq_editable`, i.e. TOML) has already refused above. Declared
/// by plist, fig and NestedText.
pub fn appendToSeq(self: *Self, path: []const AST.PathSegment, value_text: []const u8) !void {
const parsed = try self.getParsed();
const node = try parsed.ast.getValByPath(path);
if (node.kind != .sequence) return error.NotASequence;
const span = parsed.span(node);
const source = self.source.items;
if (isFlow(source, span)) {
const first = node.kind.sequence;
try self.insertFlowItem(parsed, node, span, first != null, value_text);
return;
}
// A non-flow TOML sequence is an array-of-tables; use
// `appendContainerToSeq` for those. (TOML has no block scalar array.)
if (!self.syntax().block_seq_editable) return error.NotAnInlineArray;
if (@hasDecl(Language, "appendToSeq")) return Language.appendToSeq(self, parsed, node, value_text);
const last = (try parsed.ast.lastChild(&node)) orelse return error.NotASequence;
const first_item = (try parsed.ast.child(&node)).?;
const dash_col = dashColumn(source, parsed.span(first_item).start);
const insert_at = lineEndAfter(source, parsed.span(last).end -| 1);
try self.insertSeqLine(insert_at, dash_col, value_text);
}
/// Insert `value_text` before the first item of the sequence at `path`.
///
/// **Hook** `prependToSeq(self, parsed, node, value_text) !void` — the
/// block-arm twin of `appendToSeq`'s, on the same terms.
pub fn prependToSeq(self: *Self, path: []const AST.PathSegment, value_text: []const u8) !void {
const parsed = try self.getParsed();
const node = try parsed.ast.getValByPath(path);
if (node.kind != .sequence) return error.NotASequence;
const span = parsed.span(node);
const source = self.source.items;
if (isFlow(source, span)) {
try self.prependFlowItem(parsed, node, span, node.kind.sequence != null, value_text);
return;
}
if (!self.syntax().block_seq_editable) return error.NotAnInlineArray;
if (@hasDecl(Language, "prependToSeq")) return Language.prependToSeq(self, parsed, node, value_text);
const first_item = (try parsed.ast.child(&node)) orelse return error.NotASequence;
const first_start = parsed.span(first_item).start;
const line_start = lineStartBefore(source, first_start);
const dash_col = dashColumn(source, first_start);
try self.insertSeqLine(line_start, dash_col, value_text);
}
/// Remove the item at `index` from the sequence at `path`. `index ==
/// std.math.maxInt(usize)` is the "end" sentinel — the same one
/// `parsePath` produces for the `[-]`/`[$]` append token — and means
/// "the last item" here, so `contents[-]` deletes symmetrically with
/// how it appends.
///
/// **Hook** `removeSeqItem(self, parsed, node, item, prev) !void` —
/// takes over the block arm, on the same terms as `appendToSeq`'s. It
/// is handed the resolved `item` and its predecessor rather than the
/// index, so the walk below is done once, here.
pub fn removeSeqItem(self: *Self, path: []const AST.PathSegment, index: usize) !void {
const parsed = try self.getParsed();
const node = try parsed.ast.getValByPath(path);
if (node.kind != .sequence) return error.NotASequence;
const span = parsed.span(node);
const source = self.source.items;
// Walk to the target item, keeping `prev` (its immediate
// preceding sibling, or null when it's first) alongside — both the
// `is_first` flag (for the flow path) and the block hook (whose
// callers may need to find the item's own line relative to its
// predecessor) need it, and computing it here keeps the walk to a
// single pass rather than repeating it inside the hook.
var item = (try parsed.ast.child(&node)) orelse return error.NotFound;
var prev: ?AST.Node = null;
if (index == std.math.maxInt(usize)) {
while (parsed.ast.next(&item)) |nxt| {
prev = item;
item = nxt;
}
} else {
for (0..index) |_| {
prev = item;
item = parsed.ast.next(&item) orelse return error.NotFound;
}
}
const is_first = prev == null;
const item_span = parsed.span(item);
if (isFlow(source, span)) {
try self.removeFlowItem(item_span, is_first);
return;
}
if (!self.syntax().block_seq_editable) return error.NotAnInlineArray;
if (@hasDecl(Language, "removeSeqItem")) return Language.removeSeqItem(self, parsed, node, item, prev);
const line_start = commentBlockStart(source, lineStartBefore(source, item_span.start), self.syntax().comments.style);
const del_end = lineEndAfter(source, item_span.end -| 1);
try self.replaceAtSpan(Span.init(line_start, del_end), "");
}
/// Reconcile the sequence at `path` so its items are exactly `items` —
/// each an already-serialized *scalar* value in this document's format —
/// while preserving the comments on items that survive the change.
///
/// Items are matched to the current items by abstract value (kind +
/// value, honoring multiplicity), so an item that is kept or merely
/// reordered keeps its leading and trailing comments; only a genuinely
/// new value is inserted and only a genuinely dropped value is deleted.
/// The final item order matches `items`. This is the comment-preserving
/// alternative to replacing the whole list value (which would blow every
/// item's comments away).
///
/// It is a thin orchestration over `appendToSeq` / `removeSeqItem` /
/// `reorderItems`: append the new values, delete the dropped ones, then
/// reorder to `items`. The compound edit is atomic — on any error the
/// document is restored byte-for-byte.
///
/// Declines (errors) rather than guessing when the shape isn't a flat
/// scalar list it can safely diff:
/// * a target that isn't a sequence value -> `NotASequence`;
/// * empty `items`, an empty current list, or any non-scalar item on
/// either side -> `UnsupportedShape` — the caller should fall back to
/// replacing the whole value (e.g. with `[]` for the empty case).
/// A format whose scalars cannot stand alone as a document (TOML) also
/// surfaces as `UnsupportedShape`; reconciling a TOML inline array buys
/// nothing anyway, as it carries no per-element comments.
pub fn setSequence(self: *Self, path: []const AST.PathSegment, items: []const []const u8) !void {
if (items.len == 0) return error.UnsupportedShape;
// ---- plan against the current parse (no mutation yet) ----
// Current item kinds. These borrow `self.document`, so the plan must
// be reduced to plain indices before the first edit reparses.
var cur: std.ArrayList(AST.Node.Kind) = .empty;
defer cur.deinit(self.allocator);
{
const parsed = try self.getParsed();
const node = try parsed.ast.getValByPath(path);
if (node.kind != .sequence) return error.NotASequence;
var maybe = try parsed.ast.child(&node);
while (maybe) |item| {
if (!isScalarKind(item.kind)) return error.UnsupportedShape;
try cur.append(self.allocator, item.kind);
maybe = parsed.ast.next(&item);
}
}
if (cur.items.len == 0) return error.UnsupportedShape;
// Target item kinds: parse each serialized value back to a scalar so
// matching is by abstract value, not formatting (`1` != `'1'`). A
// format whose scalar can't stand alone as a document (TOML) fails
// the parse and is declined here.
var tdocs: std.ArrayList(Document) = .empty;
defer {
for (tdocs.items) |d| d.deinit(self.allocator);
tdocs.deinit(self.allocator);
}
var tgt: std.ArrayList(AST.Node.Kind) = .empty;
defer tgt.deinit(self.allocator);
for (items) |text| {
var parser: Language.Parser = .{ .allocator = self.allocator };
const d = Language.parse(&parser, text, self.format) catch return error.UnsupportedShape;
const k = d.ast.nodes[d.ast.root].kind;
if (!isScalarKind(k)) {
d.deinit(self.allocator);
return error.UnsupportedShape;
}
try tdocs.append(self.allocator, d);
try tgt.append(self.allocator, k);
}
const m = cur.items.len;
const t = tgt.items.len;
// Occurrence index of element `i` = how many earlier elements share
// its value. (kind, occ) is the per-item identity used for matching,
// so duplicate values are paired up by their order of appearance.
const occ = struct {
fn at(kinds: []const AST.Node.Kind, i: usize) usize {
var c: usize = 0;
for (kinds[0..i]) |k| {
if (k.eql(kinds[i])) c += 1;
}
return c;
}
}.at;
// A current item survives iff some target item shares its identity.
const removed = try self.allocator.alloc(bool, m);
defer self.allocator.free(removed);
var removed_count: usize = 0;
for (0..m) |i| {
removed[i] = true;
for (0..t) |j| {
if (cur.items[i].eql(tgt.items[j]) and occ(cur.items, i) == occ(tgt.items, j)) {
removed[i] = false;
break;
}
}
if (removed[i]) removed_count += 1;
}
// A target item is an addition iff no current item shares its identity.
var additions: std.ArrayList(usize) = .empty;
defer additions.deinit(self.allocator);
for (0..t) |j| {
var present = false;
for (0..m) |i| {
if (cur.items[i].eql(tgt.items[j]) and occ(cur.items, i) == occ(tgt.items, j)) {
present = true;
break;
}
}
if (!present) try additions.append(self.allocator, j);
}
// The physical order after append+remove is survivors (old order)
// then additions (target order). `slots[s]` says what sits at index
// `s`: a kept current item or an appended target item.
const Slot = union(enum) { keep: usize, add: usize };
var slots: std.ArrayList(Slot) = .empty;
defer slots.deinit(self.allocator);
for (0..m) |i| {
if (!removed[i]) try slots.append(self.allocator, .{ .keep = i });
}
for (additions.items) |j| try slots.append(self.allocator, .{ .add = j });
// `order[k]` = the slot holding target item `k`, so a reorder by
// `order` (a full permutation) lands the sequence in target order.
const order = try self.allocator.alloc(usize, t);
defer self.allocator.free(order);
const used = try self.allocator.alloc(bool, slots.items.len);
defer self.allocator.free(used);
@memset(used, false);
for (0..t) |k| {
var found: ?usize = null;
for (slots.items, 0..) |slot, s| {
if (used[s]) continue;
const hit = switch (slot) {
.keep => |i| cur.items[i].eql(tgt.items[k]) and occ(cur.items, i) == occ(tgt.items, k),
.add => |j| j == k,
};
if (hit) {
found = s;
break;
}
}
const s = found orelse return error.UnsupportedShape; // unreachable by construction
order[k] = s;
used[s] = true;
}
// No-op: same items, same order — leave the bytes untouched so a
// redundant set never churns formatting.
var needs_reorder = false;
for (order, 0..) |o, k| {
if (o != k) {
needs_reorder = true;
break;
}
}
if (removed_count == 0 and additions.items.len == 0 and !needs_reorder) return;
// ---- apply: append, remove, reorder — atomic across all steps ----
const backup = try self.allocator.dupe(u8, self.source.items);
defer self.allocator.free(backup);
errdefer {
// Capacity only grew during the edits, so the refill cannot fail;
// `backup` parsed before, so the reparse cannot fail either.
self.source.clearRetainingCapacity();
self.source.appendSliceAssumeCapacity(backup);
self.reparse() catch {};
}
// Append first so a full replacement never empties the block mid-edit
// (an empty block sequence has no valid syntax). Appends land at the
// tail, leaving the original items' indices valid for removal.
for (additions.items) |j| try self.appendToSeq(path, items[j]);
// Remove dropped originals high-index-first so lower indices stay put.
var di: usize = m;
while (di > 0) {
di -= 1;
if (removed[di]) try self.removeSeqItem(path, di);
}
if (needs_reorder) try self.reorderItems(path, order);
}
// ============
// MOVE / REORDER
// ============
//
// Like insert/delete, these never reserialize: they relocate whole entry
// blocks (a mapping key's owned comment block + line(s), or a sequence
// item's) and reuse `replaceAtSpan` to splice + reparse. The moved bytes
// are the originals, so comments, quoting, and formatting ride along.
// Block containers tile into per-entry blocks (trailing trivia rides with
// the preceding entry); a flow sequence (`[a, b]`) reuses its original
// separators so only the items move.
/// Move the mapping entry named by `src_path` to sit immediately before
/// the entry named by `dest_path`. Both paths must name keys in the
/// *same* block mapping. The moved entry carries its owned leading
/// comment block and any trailing same-line comment; the bytes between
/// the two entries are preserved. Moving an entry to before itself (or
/// into its own comment block) is a no-op.
///
/// **Engine rule**: a SECTION node at either end is refused before any
/// splice (`CannotMoveTable` / `CannotMoveSection` /
/// `CannotMoveContainer`). An entry's block is not always the region
/// it owns: a `[header]` table's block is the header LINE, so moving
/// it would relocate the name and strand the body, and moving anything
/// else to sit before such a header lands it at the tail of the
/// *preceding* table's body, silently reparenting it. `moveContainer`
/// is the op that relocates a scattered container whole.
pub fn moveKey(self: *Self, src_path: []const AST.PathSegment, dest_path: []const AST.PathSegment) !void {
const parsed = try self.getParsed();
const src = try parsed.ast.getNodeByPath(src_path);
if (src.kind != .keyvalue) return error.NotAMapping;
const dest = try parsed.ast.getNodeByPath(dest_path);
if (dest.kind != .keyvalue) return error.NotAMapping;
if (parsed.isSection(parsed.ast.nodes[src.kind.keyvalue.value]) or
parsed.isSection(parsed.ast.nodes[dest.kind.keyvalue.value]))
return self.refuse(.move);
const source = self.source.items;
try self.moveBlock(
entryBlockStart(source, parsed.span(src), self.syntax().comments.style),
entryBlockEnd(source, parsed.span(src)),
entryBlockStart(source, parsed.span(dest), self.syntax().comments.style),
);
}
/// Move the sequence item at index `from` to index `to` (both positions
/// in the current order; standard array-move semantics — the item is
/// removed and reinserted, shifting the others to fill). A block item
/// carries its owned leading comment block. No-op when `from == to`.
pub fn moveItem(self: *Self, path: []const AST.PathSegment, from: usize, to: usize) !void {
const parsed = try self.getParsed();
const node = try parsed.ast.getValByPath(path);
if (node.kind != .sequence) return error.NotASequence;
const n = try seqLen(parsed, node);
if (from >= n or to >= n) return error.NotFound;
if (from == to) return;
// Build the post-move index order, then reorder by it.
const order = try self.allocator.alloc(usize, n);
defer self.allocator.free(order);
for (order, 0..) |*o, i| o.* = i;
const val = order[from];
if (from < to) {
var i = from;
while (i < to) : (i += 1) order[i] = order[i + 1];
} else {
var i = from;
while (i > to) : (i -= 1) order[i] = order[i - 1];
}
order[to] = val;
try self.reorderSeqNode(parsed, node, order);
}
/// Reorder the entries of the block mapping at `path` (empty path =
/// root) so the keys listed in `keys` come first, in that order; entries
/// whose key is not listed keep their original relative order and follow.
/// Keys in `keys` that the mapping does not contain are ignored. Each
/// entry's owned comments — and any interleaved blank lines / orphan
/// comments, which ride with the entry that precedes them — are
/// preserved, so no bytes are dropped. Errors on a flow mapping (`{…}`).
///
/// **Engine rule**: once the new order is known and before any splice,
/// an entry whose position actually changes and whose value is a
/// SECTION node is refused (`CannotReorderTables` /
/// `CannotReorderSections` / `CannotReorderContainers`). `[header]`
/// entries tile into blocks that stop at the *next* sibling's line —
/// so the last entry's block excludes its own body, and any container
/// that changes place strands or absorbs entries. `reorderContainers`
/// is the op that reorders scattered containers whole. Reordering an
/// inner mapping's scalar keys around a sub-table that stays put is
/// unaffected, which is why only the MOVED entries are checked.
pub fn reorderKeys(self: *Self, path: []const AST.PathSegment, keys: []const []const u8) !void {
const parsed = try self.getParsed();
const node = try parsed.ast.getValByPath(path);
if (node.kind != .mapping) return error.NotAMapping;
const first_id = node.kind.mapping orelse return; // empty mapping
const source = self.source.items;
if (isFlow(source, parsed.span(node))) return error.NotAMapping;
// Gather each entry's key (for matching) and block, in document order.
var entry_keys: std.ArrayList([]const u8) = .empty;
defer entry_keys.deinit(self.allocator);
var blocks: std.ArrayList(Block) = .empty;
defer blocks.deinit(self.allocator);
var cur = parsed.ast.nodes[first_id];
var last_end: usize = 0;
while (true) {
if (cur.kind != .keyvalue) return error.InvalidDocument;
const key_node = parsed.ast.nodes[cur.kind.keyvalue.key];
const key = switch (key_node.kind) {
.string => |s| s,
else => return error.InvalidDocument,
};
try entry_keys.append(self.allocator, key);
try blocks.append(self.allocator, .{ .start = entryBlockStart(source, parsed.span(cur), self.syntax().comments.style), .end = 0 });
last_end = entryBlockEnd(source, parsed.span(cur));
cur = parsed.ast.next(&cur) orelse break;
}
tileBlocks(blocks.items, last_end);
// Translate the requested keys into entry indices (first unused match
// wins), then reorder the blocks by that index list.
var order: std.ArrayList(usize) = .empty;
defer order.deinit(self.allocator);
const chosen = try self.allocator.alloc(bool, blocks.items.len);
defer self.allocator.free(chosen);
@memset(chosen, false);
for (keys) |k| {
for (entry_keys.items, 0..) |seen, i| {
if (!chosen[i] and std.mem.eql(u8, seen, k)) {
try order.append(self.allocator, i);
chosen[i] = true;
break;
}
}
}
// The engine's veto, before anything is spliced — over exactly the
// entries whose position this reorder changes, since an entry left
// where it was is never at risk. See the rule note above. Skipped
// at comptime for a format with no sections, where nothing could
// be refused.
if (comptime is_section_format) {
// Where each entry ends up: the listed keys first, in `order`,
// then the unlisted ones in their original relative order.
const final_pos = try self.allocator.alloc(usize, blocks.items.len);
defer self.allocator.free(final_pos);
var pos: usize = 0;
for (order.items) |i| {
final_pos[i] = pos;
pos += 1;
}
for (chosen, 0..) |c, i| if (!c) {
final_pos[i] = pos;
pos += 1;
};
var entry = parsed.ast.nodes[first_id];
var idx: usize = 0;
while (true) : (idx += 1) {
if (final_pos[idx] != idx and parsed.isSection(parsed.ast.nodes[entry.kind.keyvalue.value]))
return self.refuse(.reorder);
entry = parsed.ast.next(&entry) orelse break;
}
}
try self.reorderBlocks(blocks.items[0].start, last_end, blocks.items, order.items);
}
/// Reorder the items of the sequence at `path` (block or flow) so the
/// items at the indices listed in `indices` (positions in the current
/// order) come first, in that order; items not listed keep their
/// original relative order and follow. Out-of-range indices are ignored.
/// Block items carry their owned comments; a flow sequence keeps its
/// original separators so only the items move.
pub fn reorderItems(self: *Self, path: []const AST.PathSegment, indices: []const usize) !void {
const parsed = try self.getParsed();
const node = try parsed.ast.getValByPath(path);
if (node.kind != .sequence) return error.NotASequence;
try self.reorderSeqNode(parsed, node, indices);
}
// --- move / reorder internals ---
/// Reorder a sequence node's items by `order` (bring-to-front indices),
/// dispatching on flow vs block style.
fn reorderSeqNode(self: *Self, parsed: Document, node: AST.Node, order: []const usize) !void {
const source = self.source.items;
var spans: std.ArrayList(Span) = .empty;
defer spans.deinit(self.allocator);
var maybe = try parsed.ast.child(&node);
while (maybe) |item| {
try spans.append(self.allocator, parsed.span(item));
maybe = parsed.ast.next(&item);
}
if (spans.items.len == 0) return;
if (isFlow(source, parsed.span(node))) {
try self.reorderFlowItems(spans.items, order);
return;
}
if (!self.syntax().block_seq_editable) return error.NotAnInlineArray;
// Hook `reorderSeqItems(self, parsed, node, order) !void`, taking
// over the block arm — for a format whose item block boundaries
// can't be recovered from `spans.items[i].start` alone. The tiling/
// permutation/splice underneath is format-independent, so a hook is
// expected to reuse this file's `Block`/`fullOrder`/`appendBlockSep`
// rather than reimplement them.
if (@hasDecl(Language, "reorderSeqItems")) return Language.reorderSeqItems(self, parsed, node, order);
var blocks: std.ArrayList(Block) = .empty;
defer blocks.deinit(self.allocator);
for (spans.items) |s| {
try blocks.append(self.allocator, .{ .start = entryBlockStart(source, s, self.syntax().comments.style), .end = 0 });
}
const last_end = entryBlockEnd(source, spans.items[spans.items.len - 1]);
tileBlocks(blocks.items, last_end);
try self.reorderBlocks(blocks.items[0].start, last_end, blocks.items, order);
}
/// Splice a block container's region so the entries indexed by `order`
/// (in document order) come first, then the rest in original order.
/// `blocks` must be in document order and tile `[region_start, region_end)`.
fn reorderBlocks(self: *Self, region_start: usize, region_end: usize, blocks: []const Block, order: []const usize) !void {
const perm = try fullOrder(self.allocator, order, blocks.len);
defer self.allocator.free(perm);
const source = self.source.items;
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
for (perm) |i| try appendBlockSep(&out, self.allocator, source[blocks[i].start..blocks[i].end]);
try self.replaceAtSpan(Span.init(region_start, region_end), out.items);
}
/// Splice a flow sequence (`[a, b, …]`) so its items follow `order`,
/// reusing each slot's original separator bytes so the comma/space
/// framing is preserved while only the item contents move.
fn reorderFlowItems(self: *Self, items: []const Span, order: []const usize) !void {
const perm = try fullOrder(self.allocator, order, items.len);
defer self.allocator.free(perm);
const source = self.source.items;
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
for (perm, 0..) |src_idx, slot| {
try out.appendSlice(self.allocator, source[items[src_idx].start..items[src_idx].end]);
// Reuse the separator that originally sat after position `slot`.
if (slot + 1 < perm.len) {
try out.appendSlice(self.allocator, source[items[slot].end..items[slot + 1].start]);
}
}
try self.replaceAtSpan(Span.init(items[0].start, items[items.len - 1].end), out.items);
}
/// Move the block `[src_start, src_end)` so it begins at `dest_start`,
/// preserving the bytes between source and destination. No-op when the
/// destination falls within the source block.
fn moveBlock(self: *Self, src_start: usize, src_end: usize, dest_start: usize) !void {
if (dest_start >= src_start and dest_start <= src_end) return;
const source = self.source.items;
const moved = source[src_start..src_end];
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
if (src_end <= dest_start) {
// src precedes dest: [src][between][dest..] -> [between][src][dest..]
try appendBlockSep(&out, self.allocator, source[src_end..dest_start]);
try appendBlockSep(&out, self.allocator, moved);
try self.replaceAtSpan(Span.init(src_start, dest_start), out.items);
} else {
// dest precedes src: [dest..][between][src] -> [src][dest..][between]
try appendBlockSep(&out, self.allocator, moved);
try appendBlockSep(&out, self.allocator, source[dest_start..src_start]);
try self.replaceAtSpan(Span.init(dest_start, src_end), out.items);
}
}
// --- insert helpers (build text, then splice) ---
/// Insert `key_text<kv_sep>value_text` as a new entry in the block
/// (non-flow) mapping `mapping`, after its last existing entry (or,
/// if it has none, at a language-appropriate fallback point — see
/// below). `pub` so `ini/editor_helper.zig`'s `iniInsertKey` (INI's
/// `isFlow`-bypassing `insertKey`) can reuse it directly rather than
/// duplicate it.
pub fn insertBlockKey(self: *Self, parsed: Document, mapping: AST.Node, key_text: []const u8, value_text: []const u8) !void {
const source = self.source.items;
// Every currently-supported block-mapping language represents an
// empty mapping as `.null_` (promoted via `promoteNullToMapping`),
// never as a childless `.mapping` — so `lastChild`/`firstChildKey`
// have always found a real entry to anchor on. dotenv/.properties
// break that assumption: their root is unconditionally `.mapping`
// even for a totally empty (or comment-only) file, so the very
// first `insertKey` into a fresh file lands here with zero
// children. Fall back to column 0 and the mapping's own span end
// (its whole-file span for the flat formats' root) rather than
// unwrapping a null.
const maybe_last = try parsed.ast.lastChild(&mapping);
const col: usize = if (try parsed.ast.firstChildKey(&mapping)) |key_node|
columnOf(source, parsed.span(key_node).start)
else
0;
const insert_at = if (maybe_last) |last|
lineEndAfter(source, parsed.span(last).end -| 1)
else if (mapping.id == parsed.ast.root)
// The root's span is the whole remaining document (dotenv/
// .properties/INI's root is always `Span.init(0, input.len)`
// — see each parser's `parseOnce`), so its `.end` is already
// the right splice point even with zero existing keys.
parsed.span(mapping).end
else
// A childless NON-ROOT mapping is only reachable for INI (an
// empty `[section]` with nothing under it yet): unlike the
// root, its span is anchored at just the header's name token
// (see `ini/parser.zig`'s `parseSectionHeader`), not the
// section's body extent — splicing at `.end` would land
// inside the `[section]` line itself. Anchor on the header
// LINE's end instead; `span.start` is guaranteed to fall
// somewhere on that line, so `lineEndAfter` finds it
// regardless of where exactly within the line it points.
lineEndAfter(source, parsed.span(mapping).start);
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
if (insert_at > 0 and source[insert_at - 1] != '\n') try out.append(self.allocator, '\n');
try out.appendNTimes(self.allocator, ' ', col);
try out.appendSlice(self.allocator, key_text);
try self.writeMapValue(&out, col, value_text);
try out.append(self.allocator, '\n');
try self.replaceAtSpan(Span.init(insert_at, insert_at), out.items);
}
// --- Whole-container structural editing (section formats) ---
//
// The ops for a format whose logical containers are SCATTERED through
// the source (TOML's `[table]` headers, fig's `>` marker runs and
// re-entered headers, INI's reopened `[section]`): the generic
// line-splice ops above have no counterpart for them, because there is
// no single `[min,max)` range to splice. What there is instead is a
// DERIVED region set — `editor/regions.zig`'s `gather` — built from
// the one fact the parser records that spans cannot carry: each
// section node's header lines (`Document.node_regions`). Everything
// that only needs "where are this node's regions" is generic here, for
// every format whose `syntax().section_noun` is non-null:
//
// * `deleteContainer`, `moveContainer`, `reorderContainers` — the
// gather plus the splice-out / relocate / reorder machinery in
// `editor/regions.zig`, no format code at all;
// * the four line-splice refusals above (`deleteKey`, `moveKey`,
// `reorderKeys`, `replaceValAtPath`), which are ONE rule — a
// section node cannot be line-spliced; use the container op —
// spelled in the format's own vocabulary through `refuse`.
//
// What stays a hook is what needs to SPELL a fragment or find a name:
// `insertContainer` and `appendContainerToSeq` write a new `[header]`
// line, and `renameContainer` rewrites every place a table's name is
// spelled (its headers AND its dotted lines), which is a different
// question from where its regions are. Those three keep the
// `@hasDecl` dispatch every hook uses, and `requireSectionOp`'s
// comptime refusal for a format that declares none. See
// `docs/proposals/derived-regions.md` for the catalogue.
//
// The methods exist for every format either way — Zig has no
// conditional container-level declarations since `usingnamespace`
// went away in 0.15 (see the language-interface proposal's §8.1) —
// so a `@compileError` remains the answer for a format that is not a
// section format. The vocabulary is the operation's, not any one
// format's: TOML's `[table]`, fig's block container and INI's
// `[section]` are the same thing here, and the format's own words
// survive in its errors (`NotATable` vs `NotAContainer`) through
// `Syntax.section_noun`.
/// Whether this format has section nodes at all — a non-null
/// `section_noun` in any dialect. Comptime, so the generic ops and the
/// line-splice rule can be compiled out for every other format.
const is_section_format = blk: {
var any = false;
for (std.meta.tags(Language.Type)) |t| {
if (Language.syntax(t).section_noun != null) any = true;
}
break :blk any;
};
/// The line-splice ops the section rule refuses, and the error each
/// refusal is spelled with per `SectionNoun`.
const SectionOp = enum { delete, replace, move, reorder, not_a_section };
/// The engine's refusal in this format's vocabulary. Returns an error
/// VALUE (not a union) so a caller writes `return self.refuse(.delete)`.
fn refuse(self: *const Self, comptime op: SectionOp) error{
NotATable,
NotAContainer,
CannotDeleteTable,
CannotDeleteSection,
CannotDeleteContainer,
CannotReplaceTable,
CannotReplaceSection,
CannotReplaceContainer,
CannotMoveTable,
CannotMoveSection,
CannotMoveContainer,
CannotReorderTables,
CannotReorderSections,
CannotReorderContainers,
} {
// A format with no section nodes never reaches here (`isSection`
// is false for all its nodes), so `.container` is only the type's
// default, never a real answer.
const noun = self.syntax().section_noun orelse .container;
return switch (op) {
.not_a_section => switch (noun) {
.table => error.NotATable,
.section, .container => error.NotAContainer,
},
.delete => switch (noun) {
.table => error.CannotDeleteTable,
.section => error.CannotDeleteSection,
.container => error.CannotDeleteContainer,
},
.replace => switch (noun) {
.table => error.CannotReplaceTable,
.section => error.CannotReplaceSection,
.container => error.CannotReplaceContainer,
},
.move => switch (noun) {
.table => error.CannotMoveTable,
.section => error.CannotMoveSection,
.container => error.CannotMoveContainer,
},
.reorder => switch (noun) {
.table => error.CannotReorderTables,
.section => error.CannotReorderSections,
.container => error.CannotReorderContainers,
},
};
}
/// The section node at `path`, or the format's "not a section"
/// refusal (`NotATable` / `NotAContainer`) — for a scalar, a flow
/// container, the root, or a path that resolves to no section.
fn sectionAt(self: *const Self, parsed: Document, path: []const AST.PathSegment) !AST.Node {
const node = try parsed.ast.getValByPath(path);
if (!parsed.isSection(node)) return self.refuse(.not_a_section);
return node;
}
/// The coalesced region set of the section node `node`: its header
/// lines (creating line and every re-entry, each with its owned
/// comment block) plus every line of its subtree, in one ascending,
/// disjoint list the caller owns. `pub` for the format hooks that need
/// the regions for a different purpose than the ops below — TOML's
/// rename addresses each header region's start, and asks for
/// `merge_touching = false` so a region merged with a touching
/// neighbour does not hide one.
pub fn gatherRegions(self: *const Self, parsed: Document, node: AST.Node, merge_touching: bool) !std.ArrayList(Region) {
return regions.gatherNormalized(parsed, self.source.items, self.allocator, node, self.syntax().comments.style, merge_touching);
}
/// Byte offset just past the last line of the section node `node`'s
/// subtree — where a new sibling section can be spliced without
/// splitting it. For the `insertContainer`/`appendContainerToSeq`
/// hooks, which place a header after a parent's whole extent.
pub fn sectionExtentEnd(self: *const Self, parsed: Document, node: AST.Node) !usize {
return regions.extentEnd(parsed, self.source.items, self.allocator, node, self.syntax().comments.style);
}
/// Delete the whole container named by `path` — every scattered region
/// of its subtree, leaving interleaved foreign content untouched. For
/// TOML that is a table, array-of-tables, or single AoT element; for
/// fig a block container (a path may end in an index, deleting one
/// sequence element entire); for INI a `[section]`, reopened
/// occurrences included. A scalar or flow-valued target is refused
/// (`NotATable` / `NotAContainer`): `deleteKey`/`removeSeqItem` is the
/// op for those.
pub fn deleteContainer(self: *Self, path: []const AST.PathSegment) !void {
comptime requireSectionFormat("deleteContainer");
const parsed = try self.getParsed();
const node = try self.sectionAt(parsed, path);
var used = try self.gatherRegions(parsed, node, true);
defer used.deinit(self.allocator);
try regions.spliceOut(self, used.items);
}
/// Create a new container at `path` whose body is `body_text` (verbatim
/// entry lines, possibly empty), spliced where no existing key is
/// reparented.
///
/// **Hook** `insertContainer(self, path, body_text) !void` — a hook
/// rather than generic because it has to SPELL the new header line
/// (`[a.b]`) in the format's syntax. TOML alone declares it; fig
/// vivifies through `set`, and INI cannot vivify at all.
pub fn insertContainer(self: *Self, path: []const AST.PathSegment, body_text: []const u8) !void {
comptime requireSectionOp("insertContainer");
return Language.insertContainer(self, path, body_text);
}
/// Rename the leaf segment of the container at `path` to `new_leaf`,
/// rewriting every header that shares the prefix.
///
/// **Hook** `renameContainer(self, path, new_leaf) !void`. Only TOML
/// needs it: a fig or INI header carries its key in one tight span the
/// generic `replaceKeyAtPath` already rewrites, while a TOML rename
/// must also reach `[a.b]`, `[a.b.c]`, `[[a.b]]` and every dotted
/// line that spells the name — "where is this node's NAME written",
/// which the region table does not answer.
pub fn renameContainer(self: *Self, path: []const AST.PathSegment, new_leaf: []const u8) !void {
comptime requireSectionOp("renameContainer");
return Language.renameContainer(self, path, new_leaf);
}
/// Move the container at `src_path` before the container at
/// `dest_path` (or to EOF if null), re-emitting its scattered
/// fragments contiguously, separated from surrounding content by a
/// blank line; interleaved foreign content stays put. Both ends must
/// be section nodes. A no-op when the destination falls inside the
/// source's own region.
pub fn moveContainer(self: *Self, src_path: []const AST.PathSegment, dest_path: ?[]const AST.PathSegment) !void {
comptime requireSectionFormat("moveContainer");
const parsed = try self.getParsed();
const node = try self.sectionAt(parsed, src_path);
var used = try self.gatherRegions(parsed, node, true);
defer used.deinit(self.allocator);
// Destination: the start of the dest container's own first header
// line (owned comment block included), or EOF.
const dest_at = blk: {
if (dest_path) |dp| {
const dn = try self.sectionAt(parsed, dp);
const first = parsed.regionsOf(dn.id)[0];
break :blk regions.headerLineRegion(self.source.items, first, self.syntax().comments.style).start;
}
break :blk self.source.items.len;
};
try regions.relocate(self, used.items, dest_at);
}
/// Reorder top-level containers to the order given by `order` (their
/// keys). Each named container's scattered fragments are removed and
/// re-emitted contiguously, in `order`, at the position the earliest
/// of them currently occupies. Containers not named are untouched.
/// Each name must resolve to a section node.
pub fn reorderContainers(self: *Self, order: []const []const u8) !void {
comptime requireSectionFormat("reorderContainers");
if (order.len == 0) return;
const parsed = try self.getParsed();
const source = self.source.items;
var all: std.ArrayList(Region) = .empty;
defer all.deinit(self.allocator);
var bundles: std.ArrayList([]u8) = .empty;
defer {
for (bundles.items) |b| self.allocator.free(b);
bundles.deinit(self.allocator);
}
for (order) |name| {
const path: [1]AST.PathSegment = .{.{ .key = name }};
const node = try self.sectionAt(parsed, &path);
var used = try self.gatherRegions(parsed, node, true);
defer used.deinit(self.allocator);
const owned = try regions.captureBundle(self.allocator, source, used.items, &all);
errdefer self.allocator.free(owned);
try bundles.append(self.allocator, owned);
}
const total = regions.normalize(all.items, true);
try regions.reorderBundles(self, all.items[0..total], bundles.items);
}
/// Append a new element (body `body_text`) to the container sequence at
/// `path` — TOML's `[[header]]` array-of-tables append.
///
/// **Hook** `appendContainerToSeq(self, path, body_text) !void` — a
/// hook for the same reason as `insertContainer`: it spells the new
/// `[[header]]` line.
pub fn appendContainerToSeq(self: *Self, path: []const AST.PathSegment, body_text: []const u8) !void {
comptime requireSectionOp("appendContainerToSeq");
return Language.appendContainerToSeq(self, path, body_text);
}
/// Whether this format has the whole-container op `op` — the
/// runtime-dispatchable form of the comptime refusals, for callers
/// that must ANSWER rather than fail to compile.
///
/// The C ABI is the one such caller: its exports switch `inline else`
/// over every language at once, so naming `e.deleteContainer(…)` in
/// that switch would instantiate it for YAML and JSON too and stop the
/// build. Guarding each arm with this turns "this format has no such
/// operation" into `unsupported_format`, which is what a C caller can
/// act on. The three generic ops are had by every section format; the
/// three hooks by the formats that declare them. No format is named.
pub fn hasContainerOp(comptime op: []const u8) bool {
if (comptime isGenericContainerOp(op)) return is_section_format;
return @hasDecl(Language, op);
}
fn isGenericContainerOp(comptime op: []const u8) bool {
return std.mem.eql(u8, op, "deleteContainer") or
std.mem.eql(u8, op, "moveContainer") or
std.mem.eql(u8, op, "reorderContainers");
}
/// The comptime refusal shared by the three generic ops: a format with
/// no section nodes has nothing for them to address.
fn requireSectionFormat(comptime op: []const u8) void {
if (!is_section_format)
@compileError("'" ++ op ++ "' is a whole-container op, and '" ++ Language.name ++
"' is not a section format — its `syntax().section_noun` is null in every dialect");
}
/// The comptime refusal shared by the three hooked ops. Names the
/// format and the declaration it is missing, since "this format has
/// no such operation" is the whole content of the error.
fn requireSectionOp(comptime op: []const u8) void {
if (!@hasDecl(Language, op))
@compileError("'" ++ op ++ "' is a whole-container op that '" ++ Language.name ++
"' does not declare — see the \"Editing hooks\" block of its <lang>.zig");
}
/// How a splice's `value_text` is *spelled* — whether it stands as an
/// inline value right after `key<sep>`, or is a block construct that has
/// to descend onto the following lines.
///
/// A splice carries only text, so this is the classification the framing
/// decisions hang off. The container cases are settled by PARSING the
/// text rather than sniffing its shape: a one-entry block mapping
/// (`k: v`) is a single line with no dash and no line break, so shape
/// alone cannot tell it from a scalar — and splicing it inline yields
/// `key: k: v`, which is not YAML at all. That indistinguishability is
/// the whole reason this enum exists.
const ValueShape = enum {
/// A scalar, a flow container (`[a, b]` / `{k: v}`), or a quoted
/// string: splices directly after the separator.
inline_,
/// A block-scalar header (`|`/`>`): also splices after the separator
/// (its body is already indented), but has no flow spelling.
block_scalar,
/// A block sequence (`- a`), which descends at the KEY's own column.
block_seq,
/// A block mapping (`k: v`), which descends indented under the key.
block_map,
};
/// Classify `value_text` for the framing decisions (see `ValueShape`).
fn valueShape(self: *Self, value_text: []const u8) ValueShape {
const v = stripTrailingNewline(value_text);
const nl = std.mem.indexOfScalar(u8, v, '\n');
const first_line = std.mem.trimStart(u8, if (nl) |i| v[0..i] else v, " ");
if (first_line.len == 0) return .inline_;
if (first_line[0] == '|' or first_line[0] == '>') return .block_scalar;
// A block sequence is recognizable even on a single line (`- a`); it
// must still descend, since `key: - a` is invalid. (A serialized
// scalar that would read as a dash is quoted, so this is safe.)
if (std.mem.startsWith(u8, first_line, "- ") or std.mem.eql(u8, first_line, "-")) return .block_seq;
if (nl != null) return .block_map;
return if (self.singleLineIsBlockMapping(first_line)) .block_map else .inline_;
}
/// Whether single-line `text` is a block MAPPING entry (`k: v`) rather
/// than a scalar — the one shape that cannot be told apart by sniffing,
/// so it is read by the language's own parser.
///
/// Only asked of a format that declares `single_line_block_mapping`
/// (YAML alone today); everywhere else a `k: v` value is genuinely
/// just scalar text and must keep splicing inline. See that field.
fn singleLineIsBlockMapping(self: *Self, text: []const u8) bool {
if (!self.syntax().single_line_block_mapping) return false;
// A flow container also parses as a mapping/sequence but must stay
// inline; a quoted scalar parses as a string. Both are settled by
// the opening byte, cheaper than a parse.
switch (text[0]) {
'{', '[', '"', '\'' => return false,
else => {},
}
var parser: Language.Parser = .{ .allocator = self.allocator };
var doc = Language.parse(&parser, text, self.format) catch return false;
defer doc.deinit(self.allocator);
return doc.ast.nodes[doc.ast.root].kind == .mapping;
}
/// Append `: value` for a mapping entry whose key is already written at
/// column `col`. Scalars and block scalars stay inline (`key: value`);
/// a block collection goes on the following lines, indented (a nested
/// mapping at `col + 2`, an indentless sequence at `col`).
pub fn writeMapValue(self: *Self, out: *std.ArrayList(u8), col: usize, value_text: []const u8) !void {
const v = stripTrailingNewline(value_text);
const shape = self.valueShape(v);
const is_seq = shape == .block_seq;
// No value at all — a bare `key:` (YAML's null, and the seed `set`
// vivifies missing ancestors with). The separator's padding is
// trimmed so the line doesn't end in whitespace; formats whose
// separator carries no padding (`KEY=`) are unaffected.
if (v.len == 0) {
try out.appendSlice(self.allocator, std.mem.trimEnd(u8, try self.kvSep(), " "));
return;
}
if (shape == .inline_ or shape == .block_scalar) {
try out.appendSlice(self.allocator, try self.kvSep());
try reindentInto(out, self.allocator, v, col);
return;
}
// Block collection value: descend onto the next lines. Only
// reachable for languages with real nested block containers
// (YAML/JSON5/fig) — dotenv/.properties values are always a
// single line, so they never take this branch; the literal `:`
// below is that block-mapping syntax, not `kv_sep`.
const child_col = if (is_seq) col else col + 2;
try out.append(self.allocator, ':');
var it = std.mem.splitScalar(u8, v, '\n');
while (it.next()) |line| {
try out.append(self.allocator, '\n');
if (line.len > 0) try out.appendNTimes(self.allocator, ' ', child_col);
try out.appendSlice(self.allocator, line);
}
}
fn insertSeqLine(self: *Self, insert_at: usize, dash_col: usize, value_text: []const u8) !void {
const source = self.source.items;
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
if (insert_at > 0 and source[insert_at - 1] != '\n') try out.append(self.allocator, '\n');
try out.appendNTimes(self.allocator, ' ', dash_col);
try out.appendSlice(self.allocator, "- ");
try reindentInto(&out, self.allocator, value_text, dash_col + 2);
try out.append(self.allocator, '\n');
try self.replaceAtSpan(Span.init(insert_at, insert_at), out.items);
}
fn promoteNullToMapping(self: *Self, null_span: Span, is_root: bool, key_text: []const u8, value_text: []const u8) !void {
const source = self.source.items;
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
// A format with no bare `key: value` document form (ZON — unlike
// YAML/JSON5, whose root can be a keyless top-level mapping)
// promotes a `null` value in place to a flow container, root or
// nested alike, so this needs no `is_root`/descend distinction.
const syn = self.syntax();
if (!syn.bare_document_mapping) {
try out.appendSlice(self.allocator, syn.flow_map_open);
try out.append(self.allocator, ' ');
try out.appendSlice(self.allocator, key_text);
try out.appendSlice(self.allocator, try self.kvSep());
try out.appendSlice(self.allocator, value_text);
try out.append(self.allocator, ' ');
try out.appendSlice(self.allocator, syn.flow_map_close);
try self.replaceAtSpan(null_span, out.items);
return;
}
// `writeMapValue` emits the separator itself, so a block value
// (`- a`, `k: v`) descends onto the following lines instead of being
// jammed inline after the `:` — where it would not parse.
if (is_root) {
// Empty document: the whole source becomes a single entry.
try out.appendSlice(self.allocator, key_text);
try self.writeMapValue(&out, 0, value_text);
try out.append(self.allocator, '\n');
try self.replaceAtSpan(Span.init(0, source.len), out.items);
return;
}
const line_start = lineStartBefore(source, null_span.start);
const key_col = firstNonSpace(source, line_start) - line_start;
const child_col = key_col + 2;
try out.append(self.allocator, '\n');
try out.appendNTimes(self.allocator, ' ', child_col);
try out.appendSlice(self.allocator, key_text);
try self.writeMapValue(&out, child_col, value_text);
try self.replaceAtSpan(null_span, out.items);
}
/// Reject `value_text` that has no flow spelling before it is spliced
/// into a `{…}`/`[…]` container. A flow container holds one line of
/// comma-separated members: a block sequence (`- a`), a block mapping
/// (`k: v`), a block scalar (`|`), or anything multi-line means something
/// else entirely — or nothing at all — once wrapped in braces.
///
/// The reparse in `replaceAtSpan` is the general safety net for a bad
/// splice, but it cannot be the one that catches this: `{b: - a}` is
/// text a lenient reader may well accept as the STRING `"- a"`, so the
/// document still parses and the sequence is silently gone. Refuse up
/// front instead, and refuse with a name that says why, rather than
/// leaving the caller a generic parse failure to interpret.
///
/// A caller that needs a block value under a flow container has to
/// render the value in flow (fig's binding: `flow = 1`) or expand the
/// container to block form first.
fn requireFlowValue(self: *Self, value_text: []const u8) !void {
if (self.valueShape(value_text) != .inline_) return error.BlockValueIntoFlow;
}
/// Insert a `key: value` entry into a brace-delimited (flow) mapping,
/// matching its layout. A pretty-printed mapping — one whose closing `}`
/// sits on its own line below the members — gets the new entry on its own
/// line, indented to match the existing members (a trailing comma after
/// the last member's value, newline, member indent, `key: value`). A
/// compact single-line mapping keeps the inline `", key: value"` style.
fn insertFlowMapEntry(self: *Self, parsed: Document, node: AST.Node, span: Span, non_empty: bool, key_text: []const u8, value_text: []const u8) !void {
try self.requireFlowValue(value_text);
const source = self.source.items;
if (non_empty) {
const last = (try parsed.ast.lastChild(&node)).?;
const last_end = parsed.span(last).end;
const close = span.end - 1; // the '}'
// Multi-line layout: the closing brace is separated from the last
// member by a newline. Splice after the last member's value so the
// new entry lands on its own line, not jammed before the brace.
if (std.mem.indexOfScalar(u8, source[last_end..close], '\n') != null) {
// Column of the key's line, not the key node's own span start:
// for ZON the key span covers only the bare identifier after
// its leading `.` (the dot is a separate token), so anchoring
// on the span would misindent by one column. Every other
// format's key span already starts at that line's first
// content byte, so this is equivalent for them.
const key_node = (try parsed.ast.firstChildKey(&node)).?;
const col = columnOf(source, firstNonSpace(source, lineStartBefore(source, parsed.span(key_node).start)));
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
try out.appendSlice(self.allocator, ",\n");
try out.appendNTimes(self.allocator, ' ', col);
try out.appendSlice(self.allocator, key_text);
try out.appendSlice(self.allocator, try self.kvSep());
try out.appendSlice(self.allocator, value_text);
try self.replaceAtSpan(Span.init(last_end, last_end), out.items);
return;
}
// Single-line layout: splice right after the last member's own
// value — NOT right before the closing brace (`span.end - 1`),
// which would land inside any padding space before `}` (`{ a: 1
// }` -> `{ a: 1 , b: 2}`, swallowing the closing pad and leaving
// none before the new entry). Landing at `last_end` keeps any such
// padding after the new entry instead.
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
try out.appendSlice(self.allocator, ", ");
try out.appendSlice(self.allocator, key_text);
try out.appendSlice(self.allocator, try self.kvSep());
try out.appendSlice(self.allocator, value_text);
try self.replaceAtSpan(Span.init(last_end, last_end), out.items);
return;
}
return self.insertFlowEntry(span, key_text, value_text);
}
/// Insert the first entry into an EMPTY flow mapping (`{}` / ZON's
/// `.{}`): a tight `{key: value}` splice, unpadded — matching how
/// `insertFlowItem`'s empty-array case and the pre-existing JSON/YAML
/// empty-flow-map tests already splice (no space added around a
/// freshly-created single member).
fn insertFlowEntry(self: *Self, span: Span, key_text: []const u8, value_text: []const u8) !void {
try self.requireFlowValue(value_text);
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
try out.appendSlice(self.allocator, key_text);
try out.appendSlice(self.allocator, try self.kvSep());
try out.appendSlice(self.allocator, value_text);
const at = flowOpenEnd(self.source.items, span); // just after '{' (or ZON's '.{')
try self.replaceAtSpan(Span.init(at, at), out.items);
}
/// Insert `value_text` as the new last item of the flow sequence
/// `node`/`span`. Splices immediately after the current last
/// element rather than before the closing `]`, so a pre-existing
/// trailing comma (legal in fig/JSON5 flow arrays) isn't doubled
/// into an empty element that fails to reparse. When the array is
/// laid out one item per line, the new item follows that same
/// one-per-line style, indented to match the first item — mirroring
/// `insertFlowMapEntry`'s multi-line handling.
fn insertFlowItem(self: *Self, parsed: Document, node: AST.Node, span: Span, non_empty: bool, value_text: []const u8) !void {
try self.requireFlowValue(value_text);
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
const source = self.source.items;
if (non_empty) {
const last = (try parsed.ast.lastChild(&node)).?;
const last_end = parsed.span(last).end;
const close = span.end - 1; // the ']'
if (std.mem.indexOfScalar(u8, source[last_end..close], '\n') != null) {
const first_item = (try parsed.ast.child(&node)).?;
const col = columnOf(source, parsed.span(first_item).start);
try out.appendSlice(self.allocator, ",\n");
try out.appendNTimes(self.allocator, ' ', col);
} else {
try out.appendSlice(self.allocator, ", ");
}
try out.appendSlice(self.allocator, value_text);
try self.replaceAtSpan(Span.init(last_end, last_end), out.items);
return;
}
try out.appendSlice(self.allocator, value_text);
const at = flowOpenEnd(self.source.items, span); // just after '[' (or ZON's '.{')
try self.replaceAtSpan(Span.init(at, at), out.items);
}
fn prependFlowItem(self: *Self, parsed: Document, node: AST.Node, span: Span, non_empty: bool, value_text: []const u8) !void {
try self.requireFlowValue(value_text);
var out: std.ArrayList(u8) = .empty;
defer out.deinit(self.allocator);
try out.appendSlice(self.allocator, value_text);
// Splice right before the CURRENT first item's own span — not
// `flowOpenEnd` — so any padding space between the delimiter and that
// item (`[ a, b ]`) stays between the delimiter and the newly
// prepended item rather than being swallowed against it (`[0, a,
// b]`, an extra space where the old padding and the new separator
// collided).
const at = if (non_empty) blk: {
try out.appendSlice(self.allocator, ", ");
const first = (try parsed.ast.child(&node)).?;
break :blk parsed.span(first).start;
} else flowOpenEnd(self.source.items, span); // just after '[' (or ZON's '.{')
try self.replaceAtSpan(Span.init(at, at), out.items);
}
/// Whitespace the flow-item scan may cross while hunting for the
/// adjoining comma: spaces/tabs plus newlines, so a one-item-per-line
/// layout (item on its own indented line) is treated the same as a
/// packed single-line layout.
fn isFlowItemWs(c: u8) bool {
return c == ' ' or c == '\t' or c == '\n';
}
fn removeFlowItem(self: *Self, item_span: Span, is_first: bool) !void {
const source = self.source.items;
if (is_first) {
// Drop the item and a following ", " if present. Consuming
// forward through trailing whitespace *including newlines*
// means a standalone-line item's own indentation-and-newline
// goes with it, leaving the next item on the line the
// removed item's leading indent occupied — not a stray
// blank line.
var e = item_span.end;
while (e < source.len and isFlowItemWs(source[e])) e += 1;
if (e < source.len and source[e] == ',') {
e += 1;
while (e < source.len and isFlowItemWs(source[e])) e += 1;
}
try self.replaceAtSpan(Span.init(item_span.start, e), "");
} else {
// Drop a preceding ", " and the item. Scanning backward
// across newlines (not just spaces/tabs) is what lets this
// find the *previous* item's separator comma when the
// removed item sits alone on its own line — otherwise the
// scan stops at the newline and leaves the removed item's
// own trailing comma (if the array uses a trailing-comma
// style) dangling with nothing before it, which fails to
// reparse as an empty element.
var s = item_span.start;
while (s > 0 and isFlowItemWs(source[s - 1])) s -= 1;
if (s > 0 and source[s - 1] == ',') {
s -= 1;
while (s > 0 and isFlowItemWs(source[s - 1])) s -= 1;
}
try self.replaceAtSpan(Span.init(s, item_span.end), "");
}
}
/// Replace a span of bytes with a new span of bytes.
/// Not aware of self.format. Invalidates self.parsed until reparsed.
fn replaceSource(self: *Self, old_span: Span, text: []const u8) !void {
if (old_span.end < old_span.start or old_span.end > self.source.items.len) {
return error.InvalidSpan;
}
try self.source.replaceRange(self.allocator, old_span.start, old_span.len(), text);
}
/// After an edit, restores self.parsed so node spans are valid again.
fn reparse(self: *Self) !void {
const parsed = try self.parseSource();
self.freeDocument();
self.document = parsed;
}
fn parseSource(self: *Self) !Document {
var parser: Language.Parser = .{ .allocator = self.allocator };
return Language.parse(&parser, self.source.items, self.format);
}
fn freeDocument(self: *Self) void {
if (self.document) |parsed| {
parsed.deinit(self.allocator);
self.document = null;
}
}
pub fn deinit(self: *Self) void {
self.freeDocument();
self.source.deinit(self.allocator);
}
};
}
// ======================
// SOURCE-COORDINATE UTILS
// ======================
//
// The shared ones live in `editor/splice.zig` (the hook-facing surface) and
// are re-imported at the top of this file; what remains here is used by the
// engine alone.
/// Column of the `-` introducing the sequence item whose content begins at
/// `item_content_start`. The item's node span starts *after* the dash, so we
/// recover the dash from the first non-space byte on the item's line.
fn dashColumn(source: []const u8, item_content_start: usize) usize {
const line_start = lineStartBefore(source, item_content_start);
return firstNonSpace(source, line_start) - line_start;
}
/// Byte index just past a flow container's opening delimiter (`{`, `[`, or
/// ZON's two-byte `.{`). Used to splice the first entry/item into an empty
/// container, where `span.start` alone isn't past the delimiter for ZON.
fn flowOpenEnd(source: []const u8, span: Span) usize {
const i = firstNonSpace(source, span.start);
if (i < source.len and source[i] == '.') return i + 2; // '.' + '{'
return i + 1;
}
/// Start of a mapping entry's full block: its owned leading comment block
/// (`commentBlockStart`) at the start of the key's line. Mirrors the span math
/// `deleteKey` uses, factored out for move/reorder.
fn entryBlockStart(source: []const u8, kv_span: Span, style: CommentStyle) usize {
return commentBlockStart(source, lineStartBefore(source, kv_span.start), style);
}
/// End of a mapping entry's full block: just past the newline ending its last
/// line (or `source.len` when the final line is unterminated).
fn entryBlockEnd(source: []const u8, kv_span: Span) usize {
return lineEndAfter(source, kv_span.end -| 1);
}
/// Strip a leading line-comment `marker` (and one following space) from `line`,
/// the inverse of how `renderLineComments`/`setTrailingComment` emit a comment.
/// `line` must already have its leading whitespace trimmed. A line that doesn't
/// start with `marker` is returned unchanged.
fn stripLineCommentMarker(line: []const u8, marker: []const u8) []const u8 {
if (!std.mem.startsWith(u8, line, marker)) return line;
var rest = line[marker.len..];
if (rest.len > 0 and rest[0] == ' ') rest = rest[1..];
return rest;
}
/// The column on the line starting at `line_start` where an own-line comment's
/// marker belongs — past the line's leading whitespace, and (for a format whose
/// line prefix is STRUCTURAL, `Syntax.structural_indent`) past that prefix too.
///
/// The one place `commentOut` writes a marker and the one place `uncomment*`
/// looks for it again, so the two are inverses by construction. It matters for
/// fig alone: its `>` marker run is section depth, not indentation, so a
/// commented-out `> > size = 10` has to become `> > # size = 10` to stay
/// attached where it was — `# > > size = 10` would read as a root-level
/// comment. The `*` of a fig sequence item is NOT skipped: it introduces the
/// item, so it is part of what a comment-out has to hide.
fn commentColumn(source: []const u8, line_start: usize, structural: bool) usize {
var i = firstNonSpace(source, line_start);
if (!structural) return i;
while (i < source.len and source[i] == '>') i = firstNonSpace(source, i + 1);
return i;
}
/// Render `text` as one or more own-line comments into `out`, each line being
/// `indent` + `marker` (+ a space and the line's text, unless the line is empty)
/// + '\n'. A single trailing newline in `text` is ignored so it never yields a
/// stray empty comment line.
fn renderLineComments(
allocator: std.mem.Allocator,
out: *std.ArrayList(u8),
indent: []const u8,
marker: []const u8,
text: []const u8,
) !void {
const body = if (std.mem.endsWith(u8, text, "\n")) text[0 .. text.len - 1] else text;
var it = std.mem.splitScalar(u8, body, '\n');
while (it.next()) |line| {
try out.appendSlice(allocator, indent);
try out.appendSlice(allocator, marker);
if (line.len > 0) {
try out.append(allocator, ' ');
try out.appendSlice(allocator, line);
}
try out.append(allocator, '\n');
}
}
/// Whether a node is a leaf scalar — the kinds `setSequence` can match by value.
fn isScalarKind(kind: AST.Node.Kind) bool {
return switch (kind) {
.null_, .boolean, .string, .number, .extended => true,
.sequence, .mapping, .keyvalue, .alias => false,
};
}
/// Count the children of a container node.
fn seqLen(parsed: Document, node: AST.Node) !usize {
var n: usize = 0;
var maybe = try parsed.ast.child(&node);
while (maybe) |c| {
n += 1;
maybe = parsed.ast.next(&c);
}
return n;
}
// ── "nothing else moved": the uncomment guard ───────────────────────────────
//
// `uncommentLeading`/`uncommentDangling` strip a marker off lines the CALLER
// judged to be an entry, so the editor's half of the bargain is to prove the
// result is what was claimed: a document that parses, and that differs from
// the one before the splice only by what was ADDED to the container the lines
// sit in. Anything else — text that merged into a neighbouring block scalar,
// a line that re-opened a section and reparented the entries below it — is
// rolled back byte-for-byte with `CommentNotAnEntry`.
//
// The comparison is over the two parses, not their bytes: the after-tree is
// walked to the target container along the same path the caller named, every
// node passed on the way compared whole, and only that container is allowed
// to have grown. Comments and layout are outside the AST and so outside the
// check, which is right — a comment run losing a line is exactly what the op
// does.
/// Whether every child of `bn` still appears, in order and unchanged, among
/// the children of `an` — i.e. `an` differs from `bn` only by insertions.
/// Matching is greedy: each before-child claims the earliest after-child it
/// equals. Greedy can only fail early, never accept something it shouldn't, so
/// the failure direction is the safe one (a rollback, not a bad commit).
fn childrenOnlyGrew(b: Document, bn: AST.Node, a: Document, an: AST.Node) bool {
var b_cur = (b.ast.child(&bn) catch return false);
var a_cur = (a.ast.child(&an) catch return false);
while (b_cur) |bc| {
var matched = false;
while (a_cur) |ac| {
a_cur = a.ast.next(&ac);
if (nodesEqualDeep(b, bc.id, a, ac.id)) {
matched = true;
break;
}
}
if (!matched) return false;
b_cur = b.ast.next(&bc);
}
return true;
}
/// Structural equality of two subtrees across two parses: same kinds, same
/// scalar bytes, same children in the same order. Node ids differ between the
/// two documents, so `AST.Node.Kind.eql` (which compares child ids) cannot be
/// used for containers — only for the leaves.
fn nodesEqualDeep(b: Document, bid: AST.Node.Id, a: Document, aid: AST.Node.Id) bool {
const bn = b.ast.nodes[bid];
const an = a.ast.nodes[aid];
if (std.meta.activeTag(bn.kind) != std.meta.activeTag(an.kind)) return false;
switch (bn.kind) {
.mapping, .sequence => {
var b_cur = (b.ast.child(&bn) catch return false);
var a_cur = (a.ast.child(&an) catch return false);
while (b_cur) |bc| {
const ac = a_cur orelse return false;
if (!nodesEqualDeep(b, bc.id, a, ac.id)) return false;
b_cur = b.ast.next(&bc);
a_cur = a.ast.next(&ac);
}
return a_cur == null;
},
.keyvalue => |kv| return nodesEqualDeep(b, kv.key, a, an.kind.keyvalue.key) and
nodesEqualDeep(b, kv.value, a, an.kind.keyvalue.value),
else => return bn.kind.eql(an.kind),
}
}
/// Whether `after` differs from `before` only by nodes added to the container
/// at `path` (the root for an empty path). Every other node — including every
/// container passed through on the way down, and every sibling of the ones
/// that are — must be structurally identical.
fn addedOnlyAt(before: Document, after: Document, path: []const AST.PathSegment) bool {
return addedOnlyUnder(before, before.ast.root, after, after.ast.root, path);
}
fn addedOnlyUnder(
b: Document,
bid: AST.Node.Id,
a: Document,
aid: AST.Node.Id,
path: []const AST.PathSegment,
) bool {
const bn = b.ast.nodes[bid];
const an = a.ast.nodes[aid];
if (std.meta.activeTag(bn.kind) != std.meta.activeTag(an.kind)) return false;
if (path.len == 0) return childrenOnlyGrew(b, bn, a, an);
// Not the target yet: walk the two child lists in lockstep. They must have
// the same length and pair up, with only the child the next path segment
// names allowed to differ — and only by what is added deeper down.
var b_cur = (b.ast.child(&bn) catch return false);
var a_cur = (a.ast.child(&an) catch return false);
var index: usize = 0;
while (b_cur) |bc| {
const ac = a_cur orelse return false;
const on_path = switch (path[0]) {
.key => bc.kind == .keyvalue and ac.kind == .keyvalue and
keyNodeIs(b, bc.kind.keyvalue.key, path[0].key),
.index => index == path[0].index,
};
const b_next = if (bc.kind == .keyvalue) bc.kind.keyvalue.value else bc.id;
const a_next = if (ac.kind == .keyvalue) ac.kind.keyvalue.value else ac.id;
if (on_path) {
if (bc.kind == .keyvalue and !nodesEqualDeep(b, bc.kind.keyvalue.key, a, ac.kind.keyvalue.key))
return false;
if (!addedOnlyUnder(b, b_next, a, a_next, path[1..])) return false;
} else if (!nodesEqualDeep(b, bc.id, a, ac.id)) return false;
b_cur = b.ast.next(&bc);
a_cur = a.ast.next(&ac);
index += 1;
}
return a_cur == null;
}
/// Whether the key node `id` is the string `name` — the physical spelling a
/// path segment matches against while walking two parses side by side.
fn keyNodeIs(doc: Document, id: AST.Node.Id, name: []const u8) bool {
const k = doc.ast.nodes[id].kind;
return k == .string and std.mem.eql(u8, k.string, name);
}
/// Drop a single trailing '\n' (the serializer ends every value with one).
fn stripTrailingNewline(text: []const u8) []const u8 {
if (text.len > 0 and text[text.len - 1] == '\n') return text[0 .. text.len - 1];
return text;
}
/// Append `value_text` to `out`, re-indented so it sits at column `indent`.
/// The first line is emitted verbatim (it follows `key: ` or `- `); every
/// subsequent non-blank line is prefixed with `indent` spaces, preserving the
/// serializer's own relative indentation. One trailing '\n' is stripped.
fn reindentInto(out: *std.ArrayList(u8), allocator: std.mem.Allocator, value_text: []const u8, indent: usize) !void {
const text = stripTrailingNewline(value_text);
var it = std.mem.splitScalar(u8, text, '\n');
var first = true;
while (it.next()) |line| {
if (!first) {
try out.append(allocator, '\n');
if (line.len > 0) try out.appendNTimes(allocator, ' ', indent);
}
try out.appendSlice(allocator, line);
first = false;
}
}
// ── Comment-editing tests ──────────────────────────────────────────────────
const testing = std.testing;
fn expectCommentEdit(
comptime Lang: type,
format: Lang.Type,
input: []const u8,
expected: []const u8,
op: enum { leading, trailing },
path: []const AST.PathSegment,
text: []const u8,
) !void {
var ed: Editor(Lang) = .{ .allocator = testing.allocator, .format = format };
try ed.init(input);
defer ed.deinit();
switch (op) {
.leading => try ed.addLeadingComment(path, text),
.trailing => try ed.setTrailingComment(path, text),
}
try testing.expectEqualStrings(expected, ed.source.items);
}
test "addLeadingComment inserts an own-line comment above a YAML key" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
try expectCommentEdit(Yaml, .v1_2_2, "a: 1\nb: 2\n", "a: 1\n# note\nb: 2\n", .leading, &.{.{ .key = "b" }}, "note");
}
test "addLeadingComment matches indentation and lands nearest the key" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// Nested key: comment takes the key's 2-space indent and sits just above it,
// below the pre-existing comment.
try expectCommentEdit(
Yaml,
.v1_2_2,
"outer:\n # kept\n inner: 1\n",
"outer:\n # kept\n # new\n inner: 1\n",
.leading,
&.{ .{ .key = "outer" }, .{ .key = "inner" } },
"new",
);
}
test "setTrailingComment appends and then replaces a YAML same-line comment" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
try expectCommentEdit(Yaml, .v1_2_2, "a: 1\n", "a: 1 # done\n", .trailing, &.{.{ .key = "a" }}, "done");
// Re-setting replaces the existing trailing comment rather than nesting it.
try expectCommentEdit(Yaml, .v1_2_2, "a: 1 # old\n", "a: 1 # new\n", .trailing, &.{.{ .key = "a" }}, "new");
}
test "addLeadingComment on TOML uses #" {
if (comptime !build_options.lang_toml) return error.SkipZigTest;
try expectCommentEdit(Toml, .TOML_1_1, "a = 1\nb = 2\n", "a = 1\n# note\nb = 2\n", .leading, &.{.{ .key = "b" }}, "note");
}
// This instantiation (plus every `Editor(Fig)` call below) is what pulls
// `Editor(Fig)`'s own methods into the test build's reachability graph — `zig
// test` analyzes a generic struct's methods only once something calls them, so
// an `Editor(Fig)` that nothing instantiates is an `Editor(Fig)` nothing
// type-checks. (`fig/editor_helper.zig`'s `test` blocks are discovered through
// `fig.zig`'s own `test {}`, and carry the rest of `Editor(Fig)`'s coverage
// rather than duplicating it here; the same split holds for TOML above.)
test "addLeadingComment on fig uses # at the target's own marker depth" {
if (comptime !build_options.lang_fig) return error.SkipZigTest;
try expectCommentEdit(Fig, .Fig, "a = 1\nb = 2\n", "a = 1\n# note\nb = 2\n", .leading, &.{.{ .key = "b" }}, "note");
try expectCommentEdit(
Fig,
.Fig,
"database\n> pool\n> > size = 10\n",
"database\n> pool\n> > # note\n> > size = 10\n",
.leading,
&.{ .{ .key = "database" }, .{ .key = "pool" }, .{ .key = "size" } },
"note",
);
}
test "comment ops on JSONC use // and respect indentation" {
try expectCommentEdit(
json.Language,
.JSONC,
"{\n \"a\": 1\n}",
"{\n // note\n \"a\": 1\n}",
.leading,
&.{.{ .key = "a" }},
"note",
);
}
test "set inserts into a pretty-printed JSON object on its own line, indented" {
var ed: Editor(json.Language) = .{ .allocator = testing.allocator, .format = .JSON };
try ed.init("{\n \"a\": 1,\n \"b\": 2\n}");
defer ed.deinit();
try ed.set(&.{.{ .key = "c" }}, "3");
try testing.expectEqualStrings("{\n \"a\": 1,\n \"b\": 2,\n \"c\": 3\n}", ed.source.items);
}
test "set keeps compact single-line JSON objects inline" {
var ed: Editor(json.Language) = .{ .allocator = testing.allocator, .format = .JSON };
try ed.init("{\"a\": 1, \"b\": 2}");
defer ed.deinit();
try ed.set(&.{.{ .key = "c" }}, "3");
try testing.expectEqualStrings("{\"a\": 1, \"b\": 2, \"c\": 3}", ed.source.items);
}
test "comment ops are rejected for strict JSON" {
var ed: Editor(json.Language) = .{ .allocator = testing.allocator, .format = .JSON };
try ed.init("{\"a\":1}");
defer ed.deinit();
try testing.expectError(error.CommentsUnsupported, ed.addLeadingComment(&.{.{ .key = "a" }}, "x"));
try testing.expectError(error.CommentsUnsupported, ed.setTrailingComment(&.{.{ .key = "a" }}, "x"));
}
test "multi-line leading comment becomes one line per row" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
try expectCommentEdit(Yaml, .v1_2_2, "a: 1\n", "# one\n# two\na: 1\n", .leading, &.{.{ .key = "a" }}, "one\ntwo");
}
test "setTrailingComment rejects a multi-line comment" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init("a: 1\n");
defer ed.deinit();
try testing.expectError(error.MultilineComment, ed.setTrailingComment(&.{.{ .key = "a" }}, "x\ny"));
}
fn expectCommentDelete(
comptime Lang: type,
format: Lang.Type,
input: []const u8,
expected: []const u8,
op: enum { leading, trailing },
path: []const AST.PathSegment,
) !void {
var ed: Editor(Lang) = .{ .allocator = testing.allocator, .format = format };
try ed.init(input);
defer ed.deinit();
switch (op) {
.leading => try ed.deleteLeadingComments(path),
.trailing => try ed.deleteTrailingComment(path),
}
try testing.expectEqualStrings(expected, ed.source.items);
}
test "deleteLeadingComments removes the owned block above a YAML key" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// Only the block touching the key goes; a blank line breaks ownership, so the
// earlier comment (above the blank) stays.
try expectCommentDelete(
Yaml,
.v1_2_2,
"# top\n\n# a\n# b\nkey: 1\n",
"# top\n\nkey: 1\n",
.leading,
&.{.{ .key = "key" }},
);
// No leading comment → no-op.
try expectCommentDelete(Yaml, .v1_2_2, "key: 1\n", "key: 1\n", .leading, &.{.{ .key = "key" }});
}
test "deleteTrailingComment removes a same-line comment (YAML/JSONC), else no-op" {
if (comptime build_options.lang_yaml)
try expectCommentDelete(Yaml, .v1_2_2, "a: 1 # gone\nb: 2\n", "a: 1\nb: 2\n", .trailing, &.{.{ .key = "a" }});
// No trailing comment → no-op.
if (comptime build_options.lang_yaml)
try expectCommentDelete(Yaml, .v1_2_2, "a: 1\n", "a: 1\n", .trailing, &.{.{ .key = "a" }});
// JSONC `//` trailing.
try expectCommentDelete(json.Language, .JSONC, "{\n \"a\": 1 // x\n}", "{\n \"a\": 1\n}", .trailing, &.{.{ .key = "a" }});
}
test "ZON owned-comment scan uses // (comments.style fix)" {
if (comptime !build_options.lang_zon) return error.SkipZigTest;
try expectCommentDelete(
Zon,
.ZON,
".{\n // note\n .n = 3,\n}\n",
".{\n .n = 3,\n}\n",
.leading,
&.{.{ .key = "n" }},
);
}
test "comment delete ops are rejected for strict JSON" {
var ed: Editor(json.Language) = .{ .allocator = testing.allocator, .format = .JSON };
try ed.init("{\"a\":1}");
defer ed.deinit();
try testing.expectError(error.CommentsUnsupported, ed.deleteLeadingComments(&.{.{ .key = "a" }}));
try testing.expectError(error.CommentsUnsupported, ed.deleteTrailingComment(&.{.{ .key = "a" }}));
}
fn expectCommentGet(
comptime Lang: type,
format: Lang.Type,
input: []const u8,
/// `null` asserts the comment is ABSENT; a string asserts it is present with
/// exactly those bytes (`""` = a present-but-empty bare marker).
expected: ?[]const u8,
op: enum { leading, trailing },
path: []const AST.PathSegment,
) !void {
var ed: Editor(Lang) = .{ .allocator = testing.allocator, .format = format };
try ed.init(input);
defer ed.deinit();
const got = switch (op) {
.leading => try ed.getLeadingComment(path),
.trailing => try ed.getTrailingComment(path),
};
defer if (got) |g| testing.allocator.free(g);
if (expected) |want| {
try testing.expect(got != null);
try testing.expectEqualStrings(want, got.?);
} else {
try testing.expect(got == null);
}
}
test "getLeadingComment returns the owned block above a key, markers stripped" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
try expectCommentGet(Yaml, .v1_2_2, "# one\n# two\na: 1\n", "one\ntwo", .leading, &.{.{ .key = "a" }});
// No block above → absent (null).
try expectCommentGet(Yaml, .v1_2_2, "a: 1\nb: 2\n", null, .leading, &.{.{ .key = "b" }});
}
test "getTrailingComment returns the same-line comment, marker stripped" {
if (comptime build_options.lang_yaml) {
try expectCommentGet(Yaml, .v1_2_2, "a: 1 # done\n", "done", .trailing, &.{.{ .key = "a" }});
// No trailing comment → absent (null).
try expectCommentGet(Yaml, .v1_2_2, "a: 1\n", null, .trailing, &.{.{ .key = "a" }});
}
// JSONC `//` trailing.
try expectCommentGet(json.Language, .JSONC, "{\n \"a\": 1 // x\n}", "x", .trailing, &.{.{ .key = "a" }});
}
test "trailing comment on a block-collection key rides the key line" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
const seq = "contents: # note\n- one\n- two\n";
// get: the comment after the colon on the key's line, not after the last item.
try expectCommentGet(Yaml, .v1_2_2, seq, "note", .trailing, &.{.{ .key = "contents" }});
// set: replaces the key-line comment in place (does not append after `two`).
try expectCommentEdit(Yaml, .v1_2_2, seq, "contents: # new\n- one\n- two\n", .trailing, &.{.{ .key = "contents" }}, "new");
// set on a block key with no existing comment lands on the key line.
try expectCommentEdit(Yaml, .v1_2_2, "k:\n- a\n- b\n", "k: # added\n- a\n- b\n", .trailing, &.{.{ .key = "k" }}, "added");
// delete: removes the key-line comment.
try expectCommentDelete(Yaml, .v1_2_2, seq, "contents:\n- one\n- two\n", .trailing, &.{.{ .key = "contents" }});
}
test "trailing comment on a parent key ignores a child's same-line comment" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// The `# bc` belongs to child `b`; the parent `a` has no trailing comment.
try expectCommentGet(Yaml, .v1_2_2, "a:\n b: 1 # bc\n", null, .trailing, &.{.{ .key = "a" }});
try expectCommentGet(Yaml, .v1_2_2, "a:\n b: 1 # bc\n", "bc", .trailing, &.{ .{ .key = "a" }, .{ .key = "b" } });
}
test "getLeadingComment round-trips an empty comment line" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// A bare `#` (no text) decodes to an empty line within the block.
try expectCommentGet(Yaml, .v1_2_2, "# one\n#\n# three\na: 1\n", "one\n\nthree", .leading, &.{.{ .key = "a" }});
}
test "get distinguishes a present-but-empty comment from an absent one" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// A bare `#` is PRESENT with empty text → "" (not null).
try expectCommentGet(Yaml, .v1_2_2, "a: 1 #\n", "", .trailing, &.{.{ .key = "a" }});
try expectCommentGet(Yaml, .v1_2_2, "#\na: 1\n", "", .leading, &.{.{ .key = "a" }});
// No marker at all → absent (null).
try expectCommentGet(Yaml, .v1_2_2, "a: 1\n", null, .trailing, &.{.{ .key = "a" }});
}
test "get comment ops are rejected for strict JSON" {
var ed: Editor(json.Language) = .{ .allocator = testing.allocator, .format = .JSON };
try ed.init("{\"a\":1}");
defer ed.deinit();
try testing.expectError(error.CommentsUnsupported, ed.getLeadingComment(&.{.{ .key = "a" }}));
try testing.expectError(error.CommentsUnsupported, ed.getTrailingComment(&.{.{ .key = "a" }}));
}
// ── Flow elements own no comment (see `commentsUnanchored`) ────────────────
//
// An element or entry of a ONE-LINE flow collection sits on its parent's line,
// so the block above that line and the comment at its end are the PARENT's.
// Every op used to reach them through the item: the read returned the parent's
// text, the delete removed it, and the add spliced a comment onto the parent's
// line (on fig, whose indent is the raw line prefix, it duplicated `members = [`
// as well). Per § 3.4/§ 6.3 a comment written inside a flow collection is
// discarded at parse, so there is nothing for an item to own.
//
// Each format's test asserts all three leading ops on such an item, that the
// parent still answers with its own block, and that the two shapes whose
// elements DO begin their own lines — a multi-line flow collection, and a block
// sequence — are untouched.
/// `addLeadingComment` at `path` is refused as unanchored, and the source is
/// left byte-identical.
fn expectAddLeadingUnanchored(
comptime Lang: type,
format: Lang.Type,
input: []const u8,
path: []const AST.PathSegment,
) !void {
var ed: Editor(Lang) = .{ .allocator = testing.allocator, .format = format };
try ed.init(input);
defer ed.deinit();
try testing.expectError(error.CommentsUnanchored, ed.addLeadingComment(path, "new"));
try testing.expectEqualStrings(input, ed.source.items);
}
/// `setTrailingComment` at `path` is refused as unanchored, and the source is
/// left byte-identical.
fn expectSetTrailingUnanchored(
comptime Lang: type,
format: Lang.Type,
input: []const u8,
path: []const AST.PathSegment,
) !void {
var ed: Editor(Lang) = .{ .allocator = testing.allocator, .format = format };
try ed.init(input);
defer ed.deinit();
try testing.expectError(error.CommentsUnanchored, ed.setTrailingComment(path, "new"));
try testing.expectEqualStrings(input, ed.source.items);
}
const flow_item0: []const AST.PathSegment = &.{ .{ .key = "members" }, .{ .index = 0 } };
const flow_item1: []const AST.PathSegment = &.{ .{ .key = "members" }, .{ .index = 1 } };
const flow_members: []const AST.PathSegment = &.{.{ .key = "members" }};
const flow_entry: []const AST.PathSegment = &.{ .{ .key = "nested" }, .{ .key = "k" } };
test "TOML: a flow item on its parent's line owns no leading comment" {
if (comptime !build_options.lang_toml) return error.SkipZigTest;
const one_line = "# above members\nmembers = [\"a\", \"b\"]\n";
// Read: null through either item; the block is still `members`' own.
try expectCommentGet(Toml, .TOML_1_1, one_line, null, .leading, flow_item0);
try expectCommentGet(Toml, .TOML_1_1, one_line, null, .leading, flow_item1);
try expectCommentGet(Toml, .TOML_1_1, one_line, "above members", .leading, flow_members);
// Delete: a no-op, not a delete of the parent's block.
try expectCommentDelete(Toml, .TOML_1_1, one_line, one_line, .leading, flow_item0);
// Add: refused; there is no line the item owns to put one on.
try expectAddLeadingUnanchored(Toml, .TOML_1_1, one_line, flow_item0);
// An inline table's entry shares the line the same way.
const inline_tbl = "# above nested\nnested = { k = \"v\" }\n";
try expectCommentGet(Toml, .TOML_1_1, inline_tbl, null, .leading, flow_entry);
try expectCommentDelete(Toml, .TOML_1_1, inline_tbl, inline_tbl, .leading, flow_entry);
try expectAddLeadingUnanchored(Toml, .TOML_1_1, inline_tbl, flow_entry);
// A multi-line array's items each begin their own line: unchanged.
const multi = "# above members\nmembers = [\n \"a\",\n \"b\",\n]\n";
try expectCommentGet(Toml, .TOML_1_1, multi, null, .leading, flow_item0);
try expectCommentDelete(Toml, .TOML_1_1, multi, multi, .leading, flow_item0);
try expectCommentEdit(
Toml,
.TOML_1_1,
multi,
"# above members\nmembers = [\n # new\n \"a\",\n \"b\",\n]\n",
.leading,
flow_item0,
"new",
);
}
test "YAML: a flow item on its parent's line owns no leading comment" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
const one_line = "# above\nmembers: [a, b]\n";
try expectCommentGet(Yaml, .v1_2_2, one_line, null, .leading, flow_item0);
try expectCommentGet(Yaml, .v1_2_2, one_line, null, .leading, flow_item1);
try expectCommentGet(Yaml, .v1_2_2, one_line, "above", .leading, flow_members);
try expectCommentDelete(Yaml, .v1_2_2, one_line, one_line, .leading, flow_item0);
try expectAddLeadingUnanchored(Yaml, .v1_2_2, one_line, flow_item0);
// A flow mapping's entry shares the line the same way.
const flow_map = "# above nested\nnested: {k: v}\n";
try expectCommentGet(Yaml, .v1_2_2, flow_map, null, .leading, flow_entry);
try expectCommentDelete(Yaml, .v1_2_2, flow_map, flow_map, .leading, flow_entry);
try expectAddLeadingUnanchored(Yaml, .v1_2_2, flow_map, flow_entry);
// A block sequence's items each begin their own line: unchanged.
const block = "# above\nmembers:\n - a\n - b\n";
try expectCommentGet(Yaml, .v1_2_2, block, null, .leading, flow_item0);
try expectCommentDelete(Yaml, .v1_2_2, block, block, .leading, flow_item0);
try expectCommentEdit(Yaml, .v1_2_2, block, "# above\nmembers:\n # new\n - a\n - b\n", .leading, flow_item0, "new");
}
test "fig: a flow item on its parent's line owns no leading comment" {
if (comptime !build_options.lang_fig) return error.SkipZigTest;
const one_line = "# above\nmembers = [a, b]\n";
try expectCommentGet(Fig, .Fig, one_line, null, .leading, flow_item0);
try expectCommentGet(Fig, .Fig, one_line, null, .leading, flow_item1);
try expectCommentGet(Fig, .Fig, one_line, "above", .leading, flow_members);
try expectCommentDelete(Fig, .Fig, one_line, one_line, .leading, flow_item0);
// Refused rather than spliced: fig's indent is the raw line prefix, so the
// add used to emit `members = [# new` and duplicate the key line.
try expectAddLeadingUnanchored(Fig, .Fig, one_line, flow_item0);
// A flow object's entry shares the line the same way.
const flow_obj = "# above nested\nnested = { k = v }\n";
try expectCommentGet(Fig, .Fig, flow_obj, null, .leading, flow_entry);
try expectCommentDelete(Fig, .Fig, flow_obj, flow_obj, .leading, flow_entry);
try expectAddLeadingUnanchored(Fig, .Fig, flow_obj, flow_entry);
// A multi-line (stacked flow) list's items each begin their own line.
const multi = "# above\nmembers = [\n a,\n b,\n]\n";
try expectCommentGet(Fig, .Fig, multi, null, .leading, flow_item0);
try expectCommentDelete(Fig, .Fig, multi, multi, .leading, flow_item0);
try expectCommentEdit(Fig, .Fig, multi, "# above\nmembers = [\n # new\n a,\n b,\n]\n", .leading, flow_item0, "new");
}
test "JSONC: a flow item on its parent's line owns no leading comment" {
const one_line = "{\n // above\n \"members\": [\"a\", \"b\"]\n}";
try expectCommentGet(json.Language, .JSONC, one_line, null, .leading, flow_item0);
try expectCommentGet(json.Language, .JSONC, one_line, null, .leading, flow_item1);
try expectCommentGet(json.Language, .JSONC, one_line, "above", .leading, flow_members);
try expectCommentDelete(json.Language, .JSONC, one_line, one_line, .leading, flow_item0);
try expectAddLeadingUnanchored(json.Language, .JSONC, one_line, flow_item0);
// A one-line nested object's entry shares the line the same way.
const nested = "{\n // above\n \"nested\": { \"k\": \"v\" }\n}";
try expectCommentGet(json.Language, .JSONC, nested, null, .leading, flow_entry);
try expectCommentDelete(json.Language, .JSONC, nested, nested, .leading, flow_entry);
try expectAddLeadingUnanchored(json.Language, .JSONC, nested, flow_entry);
// Pretty-printed, one element per line: unchanged.
const multi = "{\n // above\n \"members\": [\n \"a\",\n \"b\"\n ]\n}";
try expectCommentGet(json.Language, .JSONC, multi, null, .leading, flow_item0);
try expectCommentDelete(json.Language, .JSONC, multi, multi, .leading, flow_item0);
try expectCommentEdit(
json.Language,
.JSONC,
multi,
"{\n // above\n \"members\": [\n // new\n \"a\",\n \"b\"\n ]\n}",
.leading,
flow_item0,
"new",
);
}
test "a flow item on its parent's line owns no trailing comment either" {
// The same defect, one line to the right: the comment after `]` closes the
// parent's line, and the item's window used to run right through the rest
// of the collection to reach it.
if (comptime build_options.lang_toml) {
const src = "members = [\"a\", \"b\"] # note\n";
try expectCommentGet(Toml, .TOML_1_1, src, null, .trailing, flow_item0);
try expectCommentGet(Toml, .TOML_1_1, src, "note", .trailing, flow_members);
try expectCommentDelete(Toml, .TOML_1_1, src, src, .trailing, flow_item0);
try expectSetTrailingUnanchored(Toml, .TOML_1_1, src, flow_item0);
}
if (comptime build_options.lang_yaml) {
const src = "members: [a, b] # note\n";
try expectCommentGet(Yaml, .v1_2_2, src, null, .trailing, flow_item0);
try expectCommentGet(Yaml, .v1_2_2, src, "note", .trailing, flow_members);
try expectCommentDelete(Yaml, .v1_2_2, src, src, .trailing, flow_item0);
try expectSetTrailingUnanchored(Yaml, .v1_2_2, src, flow_item0);
}
if (comptime build_options.lang_fig) {
const src = "members = [a, b] # note\n";
try expectCommentGet(Fig, .Fig, src, null, .trailing, flow_item0);
try expectCommentGet(Fig, .Fig, src, "note", .trailing, flow_members);
try expectCommentDelete(Fig, .Fig, src, src, .trailing, flow_item0);
try expectSetTrailingUnanchored(Fig, .Fig, src, flow_item0);
}
const src = "{\n \"members\": [\"a\", \"b\"] // note\n}";
try expectCommentGet(json.Language, .JSONC, src, null, .trailing, flow_item0);
try expectCommentGet(json.Language, .JSONC, src, "note", .trailing, flow_members);
try expectCommentDelete(json.Language, .JSONC, src, src, .trailing, flow_item0);
try expectSetTrailingUnanchored(json.Language, .JSONC, src, flow_item0);
}
// ── dangling-anchor tests ───────────────────────────────────────────────────
/// Write a dangling comment at `path`, read it back, then delete it — the
/// three-op cycle the anchor exists for. Asserts the source after the write,
/// the text read back, and that the delete restores `input` byte-for-byte.
fn expectDanglingCycle(
comptime Lang: type,
format: Lang.Type,
input: []const u8,
path: []const AST.PathSegment,
text: []const u8,
after_add: []const u8,
) !void {
var ed: Editor(Lang) = .{ .allocator = testing.allocator, .format = format };
try ed.init(input);
defer ed.deinit();
try testing.expect((try ed.getDanglingComment(path)) == null);
try ed.addDanglingComment(path, text);
try testing.expectEqualStrings(after_add, ed.source.items);
const got = (try ed.getDanglingComment(path)).?;
defer testing.allocator.free(got);
try testing.expectEqualStrings(text, got);
try ed.deleteDanglingComments(path);
try testing.expectEqualStrings(input, ed.source.items);
}
test "dangling comment round-trips at a YAML container's end and at the root" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// Nested: at the child depth of the container's body, after its last entry.
try expectDanglingCycle(
Yaml,
.v1_2_2,
"server:\n port: 8080\nclient:\n x: 1\n",
&.{.{ .key = "server" }},
"was: here",
"server:\n port: 8080\n # was: here\nclient:\n x: 1\n",
);
// The root (empty path): the run at the end of the document.
try expectDanglingCycle(
Yaml,
.v1_2_2,
"a: 1\nb: 2\n",
&.{},
"end of file",
"a: 1\nb: 2\n# end of file\n",
);
// Multi-line text becomes one comment line per row.
try expectDanglingCycle(Yaml, .v1_2_2, "a: 1\n", &.{}, "one\ntwo", "a: 1\n# one\n# two\n");
}
test "dangling comment round-trips in a TOML table, before any sub-table" {
if (comptime !build_options.lang_toml) return error.SkipZigTest;
try expectDanglingCycle(
Toml,
.TOML_1_1,
"[server]\nport = 8080\n\n[client]\nx = 1\n",
&.{.{ .key = "server" }},
"note",
"[server]\nport = 8080\n# note\n\n[client]\nx = 1\n",
);
// A table whose only child is a sub-table anchors after its header line —
// where `toml/printer.zig` emits the run, before the sub-tables.
try expectDanglingCycle(
Toml,
.TOML_1_1,
"[a]\n[a.b]\nx = 1\n",
&.{.{ .key = "a" }},
"note",
"[a]\n# note\n[a.b]\nx = 1\n",
);
}
test "dangling comment round-trips at a fig container's marker depth" {
if (comptime !build_options.lang_fig) return error.SkipZigTest;
try expectDanglingCycle(
Fig,
.Fig,
"database\n> host = local\n> port = 5432\n",
&.{.{ .key = "database" }},
"note",
"database\n> host = local\n> port = 5432\n> # note\n",
);
}
test "dangling comment round-trips inside a multi-line JSONC object" {
// A `//` line before the closing brace is the object's dangling run; the
// editor can address it even though the container is flow-spelled.
try expectDanglingCycle(
json.Language,
.JSONC,
"{\n \"a\": 1\n}\n",
&.{},
"note",
"{\n \"a\": 1\n // note\n}\n",
);
}
test "dangling ops decline a scalar, a one-line flow container and strict JSON" {
var ed: Editor(json.Language) = .{ .allocator = testing.allocator, .format = .JSONC };
try ed.init("{\"a\": 1, \"b\": {\"c\": 2}}");
defer ed.deinit();
// No line of its own to sit on.
try testing.expectError(error.UnsupportedShape, ed.getDanglingComment(&.{}));
try testing.expectError(error.UnsupportedShape, ed.addDanglingComment(&.{}, "x"));
// A scalar has no body to end.
try testing.expectError(error.UnsupportedShape, ed.getDanglingComment(&.{.{ .key = "a" }}));
var strict: Editor(json.Language) = .{ .allocator = testing.allocator, .format = .JSON };
try strict.init("{\n \"a\": 1\n}\n");
defer strict.deinit();
try testing.expectError(error.CommentsUnsupported, strict.getDanglingComment(&.{}));
try testing.expectError(error.CommentsUnsupported, strict.addDanglingComment(&.{}, "x"));
try testing.expectError(error.CommentsUnsupported, strict.deleteDanglingComments(&.{}));
}
test "addDanglingComment lands below a run already there" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init("a: 1\n# first\n");
defer ed.deinit();
try ed.addDanglingComment(&.{}, "second");
try testing.expectEqualStrings("a: 1\n# first\n# second\n", ed.source.items);
const got = (try ed.getDanglingComment(&.{})).?;
defer testing.allocator.free(got);
try testing.expectEqualStrings("first\nsecond", got);
}
test "a dedented comment is the next entry's leading block, not the container's dangling run" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init("server:\n port: 8080\n# about client\nclient: 1\n");
defer ed.deinit();
// Spec § 3.4: shallower than the body's child depth → it stays pending for
// the next sibling, and `server` has no dangling run at all.
try testing.expect((try ed.getDanglingComment(&.{.{ .key = "server" }})) == null);
const leading = (try ed.getLeadingComment(&.{.{ .key = "client" }})).?;
defer testing.allocator.free(leading);
try testing.expectEqualStrings("about client", leading);
}
test "a document with no trailing newline still takes a dangling comment" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init("a: 1");
defer ed.deinit();
try ed.addDanglingComment(&.{}, "note");
try testing.expectEqualStrings("a: 1\n# note\n", ed.source.items);
}
// ── comment-out / uncomment tests ───────────────────────────────────────────
/// `commentOut` at `path`, assert the source, then bring it back through the
/// leading block of `next` and assert the source is `input` byte-for-byte.
fn expectCommentOutRoundTrip(
comptime Lang: type,
format: Lang.Type,
input: []const u8,
path: []const AST.PathSegment,
commented: []const u8,
next: []const AST.PathSegment,
first_line: usize,
line_count: usize,
) !void {
var ed: Editor(Lang) = .{ .allocator = testing.allocator, .format = format };
try ed.init(input);
defer ed.deinit();
try ed.commentOut(path);
try testing.expectEqualStrings(commented, ed.source.items);
// The node is gone from the tree: the entry is trivia now. (Asserted for a
// key only — commenting out item `i` leaves whatever followed it at `i`.)
if (path.len > 0 and std.meta.activeTag(path[path.len - 1]) == .key) {
const parsed = try ed.getParsed();
try testing.expectError(error.NotFound, parsed.ast.getNodeByPath(path));
}
try ed.uncommentLeading(next, first_line, line_count);
try testing.expectEqualStrings(input, ed.source.items);
}
/// The same round trip for a LAST entry, which becomes the parent's dangling
/// run rather than any sibling's leading block.
fn expectCommentOutLastRoundTrip(
comptime Lang: type,
format: Lang.Type,
input: []const u8,
path: []const AST.PathSegment,
commented: []const u8,
container: []const AST.PathSegment,
dangling_text: []const u8,
) !void {
var ed: Editor(Lang) = .{ .allocator = testing.allocator, .format = format };
try ed.init(input);
defer ed.deinit();
try ed.commentOut(path);
try testing.expectEqualStrings(commented, ed.source.items);
const got = (try ed.getDanglingComment(container)).?;
defer testing.allocator.free(got);
try testing.expectEqualStrings(dangling_text, got);
var lines: usize = 1;
for (dangling_text) |c| {
if (c == '\n') lines += 1;
}
try ed.uncommentDangling(container, 0, lines);
try testing.expectEqualStrings(input, ed.source.items);
}
test "commentOut then uncommentLeading round-trips a YAML entry" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
try expectCommentOutRoundTrip(
Yaml,
.v1_2_2,
"server:\n port: 8080\n host: local\n",
&.{ .{ .key = "server" }, .{ .key = "port" } },
"server:\n # port: 8080\n host: local\n",
&.{ .{ .key = "server" }, .{ .key = "host" } },
0,
1,
);
}
test "commentOut leaves the entry's own leading block above it" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// `# why` is a note ON the note afterwards, and the uncomment addresses
// line 1 of the block — the caller decides which lines are an entry.
try expectCommentOutRoundTrip(
Yaml,
.v1_2_2,
"# why\na: 1\nb: 2\n",
&.{.{ .key = "a" }},
"# why\n# a: 1\nb: 2\n",
&.{.{ .key = "b" }},
1,
1,
);
}
test "commentOut round-trips a multi-line value whole" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// Every line of the block scalar takes the marker at its own indentation,
// the blank line included (bare marker, no trailing space).
try expectCommentOutRoundTrip(
Yaml,
.v1_2_2,
"text: |\n one\n\n two\nb: 2\n",
&.{.{ .key = "text" }},
"# text: |\n # one\n#\n # two\nb: 2\n",
&.{.{ .key = "b" }},
0,
4,
);
}
test "commentOut round-trips a TOML entry and a JSONC member" {
if (comptime build_options.lang_toml) {
try expectCommentOutRoundTrip(
Toml,
.TOML_1_1,
"[server]\nport = 8080\nhost = \"local\"\n",
&.{ .{ .key = "server" }, .{ .key = "port" } },
"[server]\n# port = 8080\nhost = \"local\"\n",
&.{ .{ .key = "server" }, .{ .key = "host" } },
0,
1,
);
}
// JSONC: the member's own trailing comma is commented out with it, so what
// is left is still valid.
try expectCommentOutRoundTrip(
json.Language,
.JSONC,
"{\n \"a\": 1,\n \"b\": 2\n}\n",
&.{.{ .key = "a" }},
"{\n // \"a\": 1,\n \"b\": 2\n}\n",
&.{.{ .key = "b" }},
0,
1,
);
}
test "commentOut round-trips a fig entry" {
if (comptime !build_options.lang_fig) return error.SkipZigTest;
try expectCommentOutRoundTrip(
Fig,
.Fig,
"host = local\nport = 5432\n",
&.{.{ .key = "host" }},
"# host = local\nport = 5432\n",
&.{.{ .key = "port" }},
0,
1,
);
}
test "commentOut writes a nested fig entry's marker after its `>` run" {
if (comptime !build_options.lang_fig) return error.SkipZigTest;
// The `>` run is section depth, not indentation: the marker goes after it,
// or the comment detaches to the root. Coming BACK is
// `uncommentDangling`'s here — `commentBlockStart`, which is the block
// `getLeadingComment` reports, does not climb past the `>` prefix.
var ed: Editor(Fig) = .{ .allocator = testing.allocator, .format = .Fig };
try ed.init("database\n> host = local\n> port = 5432\n");
defer ed.deinit();
try ed.commentOut(&.{ .{ .key = "database" }, .{ .key = "host" } });
try testing.expectEqualStrings("database\n> # host = local\n> port = 5432\n", ed.source.items);
}
test "commentOut round-trips a block sequence item, dash and all" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
try expectCommentOutRoundTrip(
Yaml,
.v1_2_2,
"tags:\n - a\n - b\n",
&.{ .{ .key = "tags" }, .{ .index = 0 } },
"tags:\n # - a\n - b\n",
&.{ .{ .key = "tags" }, .{ .index = 0 } },
0,
1,
);
}
test "commentOut of the last entry lands in the parent's dangling run" {
if (comptime build_options.lang_yaml) {
try expectCommentOutLastRoundTrip(
Yaml,
.v1_2_2,
"server:\n port: 8080\n host: local\nclient: 1\n",
&.{ .{ .key = "server" }, .{ .key = "host" } },
"server:\n port: 8080\n # host: local\nclient: 1\n",
&.{.{ .key = "server" }},
"host: local",
);
// The last entry of the document: the root's dangling run.
try expectCommentOutLastRoundTrip(
Yaml,
.v1_2_2,
"a: 1\nb: 2\n",
&.{.{ .key = "b" }},
"a: 1\n# b: 2\n",
&.{},
"b: 2",
);
}
if (comptime build_options.lang_toml) {
try expectCommentOutLastRoundTrip(
Toml,
.TOML_1_1,
"[server]\nport = 8080\nhost = \"local\"\n",
&.{ .{ .key = "server" }, .{ .key = "host" } },
"[server]\nport = 8080\n# host = \"local\"\n",
&.{.{ .key = "server" }},
"host = \"local\"",
);
}
if (comptime build_options.lang_fig) {
try expectCommentOutLastRoundTrip(
Fig,
.Fig,
"database\n> host = local\n> port = 5432\n",
&.{ .{ .key = "database" }, .{ .key = "port" } },
"database\n> host = local\n> # port = 5432\n",
&.{.{ .key = "database" }},
"port = 5432",
);
}
}
test "commentOut and uncomment decline strict JSON, the root, flow items and sections" {
var strict: Editor(json.Language) = .{ .allocator = testing.allocator, .format = .JSON };
try strict.init("{\n \"a\": 1\n}\n");
defer strict.deinit();
try testing.expectError(error.CommentsUnsupported, strict.commentOut(&.{.{ .key = "a" }}));
try testing.expectError(error.CommentsUnsupported, strict.uncommentLeading(&.{.{ .key = "a" }}, 0, 1));
try testing.expectError(error.CommentsUnsupported, strict.uncommentDangling(&.{}, 0, 1));
if (comptime build_options.lang_yaml) {
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init("tags: [a, b]\nk: 1\n");
defer ed.deinit();
// Inside a flow collection a marker would swallow the separator, and
// the parse discards interior comments anyway.
try testing.expectError(error.CommentsUnanchored, ed.commentOut(&.{ .{ .key = "tags" }, .{ .index = 0 } }));
try testing.expectError(error.CommentsUnanchored, ed.uncommentLeading(&.{ .{ .key = "tags" }, .{ .index = 1 } }, 0, 1));
try testing.expectError(error.UnsupportedShape, ed.uncommentDangling(&.{.{ .key = "tags" }}, 0, 1));
// The root is not an entry anything can carry.
try testing.expectError(error.UnsupportedShape, ed.commentOut(&.{}));
try testing.expectEqualStrings("tags: [a, b]\nk: 1\n", ed.source.items);
}
if (comptime build_options.lang_toml) {
var ed: Editor(Toml) = .{ .allocator = testing.allocator, .format = .TOML_1_1 };
try ed.init("[server]\nport = 8080\n");
defer ed.deinit();
// A table's span is the name inside its header; its body is lines this
// op cannot see. Same refusal `deleteKey` makes, in TOML's words.
try testing.expectError(error.CannotDeleteTable, ed.commentOut(&.{.{ .key = "server" }}));
}
}
test "uncomment refuses lines that are not an entry, byte-exactly" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// The `# two` here is CONTENT of the block scalar, not a comment: stripping
// the marker parses, but it changes `text`'s value — a node the caller
// never named. Refused and rolled back.
const inside_scalar = "text: |\n one\n # two\nb: 2\n";
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init(inside_scalar);
defer ed.deinit();
try testing.expectError(error.CommentNotAnEntry, ed.uncommentLeading(&.{.{ .key = "b" }}, 0, 1));
try testing.expectEqualStrings(inside_scalar, ed.source.items);
// Prose that does not parse as an entry: the reparse fails and
// `replaceAtSpan` rolls the splice back on its own.
const prose = "a: 1\n# just a note\nb: 2\n";
var ed2: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed2.init(prose);
defer ed2.deinit();
try testing.expect(std.meta.isError(ed2.uncommentLeading(&.{.{ .key = "b" }}, 0, 1)));
try testing.expectEqualStrings(prose, ed2.source.items);
// A line with no marker at all, and a range past the end of the block.
var ed3: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed3.init("a: 1\n# x: 2\nb: 3\n");
defer ed3.deinit();
try testing.expectError(error.NotFound, ed3.uncommentLeading(&.{.{ .key = "b" }}, 1, 1));
try testing.expectError(error.NotFound, ed3.uncommentLeading(&.{.{ .key = "b" }}, 0, 2));
// A zero-length range is a no-op.
try ed3.uncommentLeading(&.{.{ .key = "b" }}, 0, 0);
try testing.expectEqualStrings("a: 1\n# x: 2\nb: 3\n", ed3.source.items);
}
test "uncomment brings back a middle line of a block, leaving the rest commented" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init("# note\n# x: 2\nb: 3\n");
defer ed.deinit();
try ed.uncommentLeading(&.{.{ .key = "b" }}, 1, 1);
try testing.expectEqualStrings("# note\nx: 2\nb: 3\n", ed.source.items);
const parsed = try ed.getParsed();
_ = try parsed.ast.getNodeByPath(&.{.{ .key = "x" }});
}
// ── set (upsert) tests ──────────────────────────────────────────────────────
fn expectSet(
comptime Lang: type,
format: Lang.Type,
input: []const u8,
path: []const AST.PathSegment,
value: []const u8,
expected: []const u8,
) !void {
var ed: Editor(Lang) = .{ .allocator = testing.allocator, .format = format };
try ed.init(input);
defer ed.deinit();
try ed.set(path, value);
try testing.expectEqualStrings(expected, ed.source.items);
}
test "set replaces an existing YAML value" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
try expectSet(Yaml, .v1_2_2, "a: 1\nb: 2\n", &.{.{ .key = "a" }}, "9", "a: 9\nb: 2\n");
}
test "set inserts a missing top-level YAML key" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
try expectSet(Yaml, .v1_2_2, "a: 1\n", &.{.{ .key = "b" }}, "2", "a: 1\nb: 2\n");
}
test "set inserts a missing nested key under an existing mapping" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
try expectSet(
Yaml,
.v1_2_2,
"outer:\n inner: 1\n",
&.{ .{ .key = "outer" }, .{ .key = "added" } },
"2",
"outer:\n inner: 1\n added: 2\n",
);
}
test "set reframes a YAML value inline->block on replace" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// Inherits replaceValAtPath's reframing: a scalar becomes a block list
// (fig writes indentless block sequences under a key).
try expectSet(Yaml, .v1_2_2, "a: 1\n", &.{.{ .key = "a" }}, "- x\n- y", "a:\n- x\n- y\n");
}
test "set replaces an existing JSON value (replace branch is format-agnostic)" {
// The replace branch matches keys logically, so it works for strict JSON.
try expectSet(json.Language, .JSON, "{\"a\": 1}", &.{.{ .key = "a" }}, "\"x\"", "{\"a\": \"x\"}");
}
test "set creates a new JSON key, quoting it for the format" {
// The insert branch renders the logical key into JSON syntax (`b` -> `"b"`),
// so creating a not-yet-present key produces valid JSON.
try expectSet(json.Language, .JSON, "{\"a\": 1}", &.{.{ .key = "b" }}, "2", "{\"a\": 1, \"b\": 2}");
// A key needing escaping is escaped, not spliced raw.
try expectSet(json.Language, .JSON, "{}", &.{.{ .key = "a\"b" }}, "1", "{\"a\\\"b\": 1}");
}
test "set rejects a path that does not end in a key" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init("a:\n - 1\n");
defer ed.deinit();
try testing.expectError(error.NotAMapping, ed.set(&.{ .{ .key = "a" }, .{ .index = 0 } }, "9"));
try testing.expectError(error.NotAMapping, ed.set(&.{}, "9"));
}
test "set auto-vivifies missing intermediate containers" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init("a: 1\n");
defer ed.deinit();
// Parent `missing` does not exist: `set` seeds it as an empty map, then
// lands the leaf. The existing `a: 1` is untouched.
try ed.set(&.{ .{ .key = "missing" }, .{ .key = "leaf" } }, "2");
try testing.expect(std.mem.indexOf(u8, ed.source.items, "a: 1") != null);
const leaf = try ed.getParsed();
const v = try leaf.ast.getValByPath(&.{ .{ .key = "missing" }, .{ .key = "leaf" } });
try testing.expectEqualStrings("2", v.kind.number.raw);
}
test "set vivifies a nested path through an empty node" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// A null is a container waiting to exist, not data — so navigation failing
// through one is vivifiable, unlike failing through a scalar (next test).
// An empty document's root:
try expectSet(Yaml, .v1_2_2, "", &.{ .{ .key = "a" }, .{ .key = "b" } }, "1", "a:\n b: 1\n");
try expectSet(
Yaml,
.v1_2_2,
"",
&.{ .{ .key = "a" }, .{ .key = "b" }, .{ .key = "c" } },
"1",
"a:\n b:\n c: 1\n",
);
// And a bare `key:` standing where an intermediate mapping should be.
try expectSet(
Yaml,
.v1_2_2,
"title: t\na:\n",
&.{ .{ .key = "a" }, .{ .key = "b" }, .{ .key = "c" } },
"1",
"title: t\na:\n b:\n c: 1\n",
);
}
test "set does not clobber a scalar standing where a parent map should be" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init("a: 1\n");
defer ed.deinit();
// `a` is a scalar, not a map: descending into it for `b` is a real type
// error (`NotAMapping`), not a missing key to vivify — `a: 1` stays intact.
try testing.expectError(error.NotAMapping, ed.set(&.{ .{ .key = "a" }, .{ .key = "b" } }, "2"));
try testing.expectEqualStrings("a: 1\n", ed.source.items);
}
test "set lands a single-entry mapping value like any other mapping value" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// A one-entry map renders `k: v` — the shape a scalar has — so every splice
// path used to read it as one and fail. All three branches of `set` (insert,
// nested insert, replace) must treat it as the block mapping it is, exactly
// as they already treated a two-entry map.
try expectSet(Yaml, .v1_2_2, "a: 1\n", &.{.{ .key = "fresh" }}, "k: v\n", "a: 1\nfresh:\n k: v\n");
try expectSet(
Yaml,
.v1_2_2,
"outer:\n inner: 1\n",
&.{ .{ .key = "outer" }, .{ .key = "added" } },
"k: v\n",
"outer:\n inner: 1\n added:\n k: v\n",
);
try expectSet(Yaml, .v1_2_2, "a: 1\n", &.{.{ .key = "a" }}, "k: v\n", "a:\n k: v\n");
}
test "set rolls back a vivified ancestor when the leaf insert fails" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init("title: t\n");
defer ed.deinit();
// Malformed value text: `a` is seeded, then the leaf insert's reparse
// rejects it. Two splices, one outcome — `Err` has to mean the document is
// untouched, or a caller that retries is editing a document it never asked
// for. Without the rollback the seeded `a:` would survive.
try testing.expectError(
error.UnexpectedToken,
ed.set(&.{ .{ .key = "a" }, .{ .key = "b" } }, "[unclosed"),
);
try testing.expectEqualStrings("title: t\n", ed.source.items);
}
test "set reports the flow container, not a missing key, when a block value can't land" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
var ed: Editor(Yaml) = .{ .allocator = testing.allocator, .format = .v1_2_2 };
try ed.init("a: {b: 1}\n");
defer ed.deinit();
// The parent exists and IS a mapping — just a flow one. Falling back to the
// replace branch's `NotFound` would send the caller after a key that isn't
// the problem.
try testing.expectError(
error.BlockValueIntoFlow,
ed.set(&.{ .{ .key = "a" }, .{ .key = "c" } }, "- q\n"),
);
try testing.expectEqualStrings("a: {b: 1}\n", ed.source.items);
}
test "yaml set vivifies a fresh nested path as BLOCK containers" {
if (comptime !build_options.lang_yaml) return error.SkipZigTest;
// YAML seeds missing ancestors as bare `key:` (null), which `insertKey`
// promotes to a real block mapping — so a fresh nested path reads like
// hand-written YAML instead of a flow chain (`a: {b: {c: 1}}`).
try expectSet(
Yaml,
.v1_2_2,
"title: t\n",
&.{ .{ .key = "a" }, .{ .key = "b" }, .{ .key = "c" } },
"1",
"title: t\na:\n b:\n c: 1\n",
);
// And the payoff: a BLOCK value now lands at a fresh nested path, which no
// flow seed could ever hold.
try expectSet(
Yaml,
.v1_2_2,
"title: t\n",
&.{ .{ .key = "a" }, .{ .key = "b" } },
"- q\n",
"title: t\na:\n b:\n - q\n",
);
try expectSet(
Yaml,
.v1_2_2,
"title: t\n",
&.{ .{ .key = "a" }, .{ .key = "b" } },
"k: v\n",
"title: t\na:\n b:\n k: v\n",
);
// The seeded line carries no trailing whitespace.
try testing.expect(std.mem.indexOf(u8, "title: t\na:\n b:\n c: 1\n", " \n") == null);
}
test "non-YAML formats keep vivifying through flow seeds" {
// The empty seed is YAML-specific: `a =` is not a TOML value, and the flow
// chain is the idiomatic intermediate form for the dotted-key formats.
if (comptime build_options.lang_toml) {
try expectSet(
Toml,
.TOML_1_0,
"title = 't'\n",
&.{ .{ .key = "a" }, .{ .key = "b" } },
"1",
"title = 't'\na = { b = 1 }\n",
);
}
try expectSet(
json.Language,
.JSON,
"{\"t\": 1}",
&.{ .{ .key = "a" }, .{ .key = "b" } },
"2",
"{\"t\": 1, \"a\": {\"b\": 2}}",
);
}
test "fig set vivifies a nested path from an empty document" {
if (comptime !build_options.lang_fig) return error.SkipZigTest;
var ed: Editor(Fig) = .{ .allocator = testing.allocator, .format = .Fig };
try ed.init(""); // empty fig doc = empty root map (seedable from scratch)
defer ed.deinit();
try ed.set(&.{ .{ .key = "a" }, .{ .key = "b" }, .{ .key = "c" } }, "hi");
// The seeded parents nest as flow maps; the leaf reads back through the path.
const parsed = try ed.getParsed();
const v = try parsed.ast.getValByPath(&.{ .{ .key = "a" }, .{ .key = "b" }, .{ .key = "c" } });
try testing.expectEqualStrings("hi", v.kind.string);
}
// ── dotenv / .properties (flat `KEY=value`) ─────────────────────────────────
//
// Both are flat-only (root mapping, no nesting/sequences), so unlike
// YAML/TOML/fig their root is never `.null_` — even a totally empty file
// parses as an empty (childless) `.mapping`. That's exactly the case
// `insertBlockKey` used to `.?`-unwrap into a panic on (see its comment);
// these tests exercise that path directly via `set`'s from-empty seed, which
// is also how the CLI's `set` on a freshly created file behaves.
test "dotenv set seeds the first key into an empty document" {
if (comptime !build_options.lang_dotenv) return error.SkipZigTest;
try expectSet(Dotenv, .DOTENV, "", &.{.{ .key = "FOO" }}, "bar", "FOO=bar\n");
}
test "dotenv set inserts a second key using '=', no spaces" {
if (comptime !build_options.lang_dotenv) return error.SkipZigTest;
try expectSet(Dotenv, .DOTENV, "FOO=bar\n", &.{.{ .key = "BAZ" }}, "qux", "FOO=bar\nBAZ=qux\n");
}
test "dotenv set replaces an existing value" {
if (comptime !build_options.lang_dotenv) return error.SkipZigTest;
try expectSet(Dotenv, .DOTENV, "FOO=bar\n", &.{.{ .key = "FOO" }}, "baz", "FOO=baz\n");
}
test "dotenv deleteKey removes the only entry, leaving an empty file" {
if (comptime !build_options.lang_dotenv) return error.SkipZigTest;
var ed: Editor(Dotenv) = .{ .allocator = testing.allocator, .format = .DOTENV };
try ed.init("FOO=bar\n");
defer ed.deinit();
try ed.deleteKey(&.{.{ .key = "FOO" }});
try testing.expectEqualStrings("", ed.source.items);
// Deleting down to empty round-trips back through the same from-empty
// insert path a from-scratch `set` would use.
try ed.set(&.{.{ .key = "AGAIN" }}, "v2");
try testing.expectEqualStrings("AGAIN=v2\n", ed.source.items);
}
test "dotenv comment ops use # and round-trip" {
if (comptime !build_options.lang_dotenv) return error.SkipZigTest;
var ed: Editor(Dotenv) = .{ .allocator = testing.allocator, .format = .DOTENV };
try ed.init("FOO=bar\n");
defer ed.deinit();
try ed.addLeadingComment(&.{.{ .key = "FOO" }}, "explaining foo");
try ed.setTrailingComment(&.{.{ .key = "FOO" }}, "inline note");
try testing.expectEqualStrings("# explaining foo\nFOO=bar # inline note\n", ed.source.items);
const leading = (try ed.getLeadingComment(&.{.{ .key = "FOO" }})).?;
defer testing.allocator.free(leading);
try testing.expectEqualStrings("explaining foo", leading);
const trailing = (try ed.getTrailingComment(&.{.{ .key = "FOO" }})).?;
defer testing.allocator.free(trailing);
try testing.expectEqualStrings("inline note", trailing);
}
test "properties set seeds the first key into an empty document" {
if (comptime !build_options.lang_properties) return error.SkipZigTest;
try expectSet(Properties, .PROPERTIES, "", &.{.{ .key = "foo" }}, "bar", "foo=bar\n");
}
test "properties set inserts a second key using '=', no spaces" {
if (comptime !build_options.lang_properties) return error.SkipZigTest;
try expectSet(Properties, .PROPERTIES, "foo=bar\n", &.{.{ .key = "baz" }}, "qux", "foo=bar\nbaz=qux\n");
}
test "properties deleteKey removes the only entry, leaving an empty file" {
if (comptime !build_options.lang_properties) return error.SkipZigTest;
var ed: Editor(Properties) = .{ .allocator = testing.allocator, .format = .PROPERTIES };
try ed.init("foo=bar\n");
defer ed.deinit();
try ed.deleteKey(&.{.{ .key = "foo" }});
try testing.expectEqualStrings("", ed.source.items);
try ed.set(&.{.{ .key = "again" }}, "v2");
try testing.expectEqualStrings("again=v2\n", ed.source.items);
}
// ── INI (`[section]` + flat `key = value`) ──────────────────────────────────
//
// Basic root-level/parameter sanity checks only — the same level of coverage
// TOML/fig/ZON leave here (one "uses the right marker" test apiece). The
// section-nesting behavior (`iniInsertKey`/`isSectionHeaderLine`,
// the `set` auto-vivify exclusion) is exercised in `ini/editor_helper.zig`,
// next to that logic.
test "ini set seeds the first root key into an empty document" {
if (comptime !build_options.lang_ini) return error.SkipZigTest;
try expectSet(Ini, .INI, "", &.{.{ .key = "name" }}, "fig", "name = fig\n");
}
test "ini set inserts a second root key using ' = '" {
if (comptime !build_options.lang_ini) return error.SkipZigTest;
try expectSet(Ini, .INI, "name = fig\n", &.{.{ .key = "lang" }}, "zig", "name = fig\nlang = zig\n");
}
test "ini comment ops: leading works with ';', trailing is unsupported" {
if (comptime !build_options.lang_ini) return error.SkipZigTest;
var ed: Editor(Ini) = .{ .allocator = testing.allocator, .format = .INI };
try ed.init("name = fig\n");
defer ed.deinit();
try ed.addLeadingComment(&.{.{ .key = "name" }}, "a language");
try testing.expectEqualStrings("; a language\nname = fig\n", ed.source.items);
const leading = (try ed.getLeadingComment(&.{.{ .key = "name" }})).?;
defer testing.allocator.free(leading);
try testing.expectEqualStrings("a language", leading);
try testing.expectError(error.CommentsUnsupported, ed.setTrailingComment(&.{.{ .key = "name" }}, "note"));
try testing.expectError(error.CommentsUnsupported, ed.getTrailingComment(&.{.{ .key = "name" }}));
try testing.expectError(error.CommentsUnsupported, ed.deleteTrailingComment(&.{.{ .key = "name" }}));
}