Module vim 

Vim-mode engine.

Implements a command grammar of the form

Command := count? (operator count? (motion | text-object)
                  | motion
                  | insert-entry
                  | misc)

The parser is a small state machine driven by one Input at a time. Motions and text objects produce a [Range] (with inclusive/exclusive / linewise classification). A single Operator implementation applies a range — so dw, d$, daw, and visual d all go through the same code path.

The most recent mutating command is stored in VimState::last_change so . can replay it.

Roadmap

Tracked in the original plan at ~/.claude/plans/look-at-the-vim-curried-fern.md. Phases still outstanding — each one can land as an isolated PR.

P3 — Registers & marks

• TODO: RegisterBank indexed by char:
  • unnamed "", last-yank "0, small-delete "-
  • named "a-"z (uppercase "A-"Z appends instead of overwriting)
  • blackhole "_
  • system clipboard "+ / "* (wire to crate::clipboard::Clipboard)
  • read-only ":, "., "% — surface in :reg output
• TODO: route every yank / cut / paste through the bank. Parser needs a "{reg} prefix state that captures the target register before a count / operator.
• TODO: m{a-z} sets a mark in a HashMap<char, (buffer_id, row, col)>; 'x jumps to the line (FirstNonBlank), `x to the exact cell. Uppercase marks are global across tabs; lowercase are per-buffer.
• TODO: '' and `` jump to the last-jump position; '[ '] '< '> bound the last change / visual region.
• TODO: :reg and :marks ex commands.

P4 — Macros

• TODO: q{a-z} starts recording raw Inputs into the register; next q stops.
• TODO: @{a-z} replays the register by re-feeding inputs through step. @@ repeats the last macro. Nested macros need a sane depth cap (e.g. 100) to avoid runaway loops.
• TODO: ensure recording doesn’t capture the initial q{a-z} itself.

P6 — Polish (still outstanding)

• TODO: indent operators > / < (with line + text-object targets).
• TODO: format operator = — map to whatever SQL formatter we wire up; for now stub that returns the range unchanged with a toast.
• TODO: case operators gU / gu / g~ on a range (already have single-char ~).
• TODO: screen motions H / M / L once we track the render viewport height inside Editor.
• TODO: scroll-to-cursor motions zz / zt / zb.

Known substrate / divergence notes

• TODO: insert-mode indent helpers — Ctrl-t / Ctrl-d (increase / decrease indent on current line) and Ctrl-r <reg> (paste from a register). Ctrl-r needs the RegisterBank from P3 to be useful.
• TODO: / and ? search prompts still live in the host/src/lib.rs. The plan calls for moving them into the editor (so the editor owns last_search_pattern rather than the TUI loop). Safe to defer.

Structs

InsertSession

LastVisual

Saved visual-mode anchor + cursor for gv (re-enters the last visual selection). mode carries which visual flavour to restore; anchor / cursor mean different things per flavour:

SearchPrompt

Active / or ? search prompt. Text mutations drive the textarea’s live search pattern so matches highlight as the user types.

VimState

Enums

InsertDir

Direction for insert-mode arrow movement.

InsertEntry

InsertReason

LastChange

Information needed to replay a mutating change via ..

LastHorizontalMotion

Tracks which kind of horizontal jump was last performed so ; / , can dispatch to the correct repeat handler.

Mode

Motion

Operator

Pending

RangeKind

Classification determines how operators treat the range end.

ScrollDir

Scroll direction for scroll_full_page, scroll_half_page, and scroll_line controller methods.

TextObject

Functions

matching_tag_pair

Resolve the HTML/XML tag-name pair under the cursor for matchparen-style highlight (#243). Returns [(row, name_start_col, name_end_col); 2] for the tag under the cursor and its structural partner, or None when the cursor is not on a tag name or the tag is unpaired. Char-column ranges (display), consistent with motions::matching_bracket_pos.

op_is_change

true when op records a last_change entry for dot-repeat purposes. Promoted to pub in Phase 6.6e so hjkl-vim::normal can use it without duplicating the logic.

parse_motion

Parse the first key of a normal/visual-mode motion. Returns None for keys that don’t start a motion (operator keys, command keys, etc.). Promoted to pub in Phase 6.6e so hjkl-vim::normal can call it.