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pub mod ast;
use crate::lexer::{Token, TokenInfo, Lexer};
use crate::errors::{CompileError, SourceLocation, SourceFile, find_similar_keyword, ENGLISH_KEYWORDS};
use ast::*;
// Type aliases for complex nested types
type TreatingClause = (Expr, Expr);
type LoopExpansion = (String, Expr, Option<TreatingClause>);
type PathInfo = Result<Expr, LoopExpansion>;
pub struct Parser {
tokens: Vec<TokenInfo>,
pos: usize,
source_file: Option<SourceFile>,
// True while parsing a sub-expression where `to`/`of` is reserved for an
// enclosing statement's own grammar rather than available as this
// sub-expression's call connector (plan 270 G1 made `to`/`of`/`with`
// universal call connectors, which collides with older grammars that
// already claim one of those words immediately after a value position:
// the append separator `to`, a range bound's `to`, or an index's `of`).
// Without this, e.g. the `id` in `append id of item to out` would
// greedily read `to out` as its own call tail via the generic
// `allow_to: true` path, leaving no `to` for the append statement
// itself - see `parse_primary_reserving`.
suppress_to_connector: bool,
suppress_of_connector: bool,
// True while parsing the body of one `but if`/`otherwise` branch. The
// branch is already inside the outer conditional-sugar chain, so any
// `but if` suffix on the branch statement itself must be ignored; the
// outer chain owns all of the conditions. This keeps the branch parser
// generic: it can hand any statement kind to the normal statement parser
// and still not double-consume the chain.
suppress_conditional_suffix: bool,
// True when parsing a `--shared` library input. A library file is a
// collection of function definitions and legitimately ends mid-body at
// EOF (its last function has no trailing blank line), so the
// "function still open at end of file" warning (BUGS_FOUND #5) is
// suppressed in this mode — it only fires for an executable program,
// where a function body that runs to EOF has almost certainly swallowed
// the program's top-level entry code.
shared_mode: bool,
// True once a `Library <name> version "..."` declaration has been
// parsed at the top level. A library file legitimately consists only
// of function definitions with no top-level entry code, so its last
// function body routinely runs to EOF with no closing blank line —
// exactly the shape the BUGS_FOUND #5 "function still open at end of
// file" warning misreads as "the program was swallowed". Like
// `shared_mode`, this suppresses that warning, but it also covers the
// case where a library file is compiled *without* `--shared` (e.g. the
// `examples/` compile check in `test.sh`): a library with no
// top-level entry is correct by construction, not a mistake.
saw_library_decl: bool,
// Non-fatal diagnostics collected during parsing (currently the #5
// "function still open at end of file" warning). The driver prints
// these after a successful parse; they never abort compilation.
pub warnings: Vec<CompileError>,
}
#[cfg(test)]
mod buffer_copy_statement_tests;
#[cfg(test)]
mod file_line_read_and_seek_tests;
#[cfg(test)]
mod buffer_declaration_tests;
#[cfg(test)]
mod to_connector_tests;
#[cfg(test)]
mod possessive_property_unit_tests;
mod declarations;
mod io;
mod collections;
mod functions;
mod control_flow;
mod expressions;
mod statements;
impl Parser {
pub fn new(tokens: Vec<TokenInfo>) -> Self {
Parser {
tokens,
pos: 0,
source_file: None,
suppress_to_connector: false,
suppress_of_connector: false,
suppress_conditional_suffix: false,
shared_mode: false,
saw_library_decl: false,
warnings: Vec::new(),
}
}
pub fn with_source(mut self, filename: &str, content: &str) -> Self {
self.source_file = Some(SourceFile::new(filename, content));
self
}
/// Mark this parse as a `--shared` library build, suppressing the
/// "function still open at end of file" warning (legitimate for a
/// library file whose last function has no trailing blank line).
pub fn with_shared_mode(mut self, shared: bool) -> Self {
self.shared_mode = shared;
self
}
fn current(&self) -> &Token {
self.tokens.get(self.pos).map(|t| &t.token).unwrap_or(&Token::EOF)
}
fn current_info(&self) -> Option<&TokenInfo> {
self.tokens.get(self.pos)
}
fn current_location(&self) -> Option<SourceLocation> {
if let (Some(info), Some(ref src)) = (self.current_info(), &self.source_file) {
Some(src.make_location(info.line, info.column))
} else {
None
}
}
/// Recover the identifier spelling the user actually wrote at the
/// current token. The lexer canonicalises aliases (`length` →
/// `Token::Size`, `ms` → `Token::Milliseconds`, …) so by the time
/// `check_not_keyword` runs the original text is gone from the token;
/// this reads it back from the source line so the diagnostic can name
/// the word the user typed rather than the internal canonical keyword
/// (BUGS_FOUND #6).
fn current_lexeme(&self) -> Option<String> {
let loc = self.current_location()?;
let chars: Vec<char> = loc.line_content.chars().collect();
let start = loc.column.saturating_sub(1);
let mut iter = chars.into_iter().skip(start);
let first = iter.next()?;
if !(first.is_ascii_alphabetic() || first == '_') {
return None;
}
let mut out = String::new();
out.push(first);
for c in iter {
if c.is_ascii_alphanumeric() || c == '_' {
out.push(c);
} else {
break;
}
}
Some(out)
}
fn peek(&self, offset: usize) -> &Token {
self.tokens.get(self.pos + offset).map(|t| &t.token).unwrap_or(&Token::EOF)
}
fn advance(&mut self) -> Token {
let tok = self.current().clone();
self.pos += 1;
tok
}
fn skip_noise(&mut self) {
while matches!(self.current(), Token::Newline) {
self.advance();
}
}
fn skip_all_whitespace(&mut self) {
while matches!(self.current(), Token::Newline | Token::ParagraphBreak) {
self.advance();
}
}
/// Consume a period only when it is the separator before an if-chain continuation
/// (`but`, `else`, `otherwise`).
fn consume_period_before_else_chain(&mut self) {
if *self.current() != Token::Period {
return;
}
let saved = self.pos;
self.advance();
self.skip_all_whitespace();
if !matches!(self.current(), Token::But | Token::Else | Token::Otherwise) {
self.pos = saved;
}
}
#[allow(dead_code)]
fn skip_newlines(&mut self) {
while matches!(self.current(), Token::Newline | Token::ParagraphBreak) {
self.advance();
}
}
fn expect(&mut self, expected: &Token) -> bool {
if self.current() == expected {
self.advance();
true
} else {
false
}
}
}