init

vim/textObjects.ts

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+/**
+ * Vim Text Object Finding
+ *
+ * Functions for finding text object boundaries (iw, aw, i", a(, etc.)
+ */
+
+import {
+  isVimPunctuation,
+  isVimWhitespace,
+  isVimWordChar,
+} from '../utils/Cursor.js'
+import { getGraphemeSegmenter } from '../utils/intl.js'
+
+export type TextObjectRange = { start: number; end: number } | null
+
+/**
+ * Delimiter pairs for text objects.
+ */
+const PAIRS: Record<string, [string, string]> = {
+  '(': ['(', ')'],
+  ')': ['(', ')'],
+  b: ['(', ')'],
+  '[': ['[', ']'],
+  ']': ['[', ']'],
+  '{': ['{', '}'],
+  '}': ['{', '}'],
+  B: ['{', '}'],
+  '<': ['<', '>'],
+  '>': ['<', '>'],
+  '"': ['"', '"'],
+  "'": ["'", "'"],
+  '`': ['`', '`'],
+}
+
+/**
+ * Find a text object at the given position.
+ */
+export function findTextObject(
+  text: string,
+  offset: number,
+  objectType: string,
+  isInner: boolean,
+): TextObjectRange {
+  if (objectType === 'w')
+    return findWordObject(text, offset, isInner, isVimWordChar)
+  if (objectType === 'W')
+    return findWordObject(text, offset, isInner, ch => !isVimWhitespace(ch))
+
+  const pair = PAIRS[objectType]
+  if (pair) {
+    const [open, close] = pair
+    return open === close
+      ? findQuoteObject(text, offset, open, isInner)
+      : findBracketObject(text, offset, open, close, isInner)
+  }
+
+  return null
+}
+
+function findWordObject(
+  text: string,
+  offset: number,
+  isInner: boolean,
+  isWordChar: (ch: string) => boolean,
+): TextObjectRange {
+  // Pre-segment into graphemes for grapheme-safe iteration
+  const graphemes: Array<{ segment: string; index: number }> = []
+  for (const { segment, index } of getGraphemeSegmenter().segment(text)) {
+    graphemes.push({ segment, index })
+  }
+
+  // Find which grapheme index the offset falls in
+  let graphemeIdx = graphemes.length - 1
+  for (let i = 0; i < graphemes.length; i++) {
+    const g = graphemes[i]!
+    const nextStart =
+      i + 1 < graphemes.length ? graphemes[i + 1]!.index : text.length
+    if (offset >= g.index && offset < nextStart) {
+      graphemeIdx = i
+      break
+    }
+  }
+
+  const graphemeAt = (idx: number): string => graphemes[idx]?.segment ?? ''
+  const offsetAt = (idx: number): number =>
+    idx < graphemes.length ? graphemes[idx]!.index : text.length
+  const isWs = (idx: number): boolean => isVimWhitespace(graphemeAt(idx))
+  const isWord = (idx: number): boolean => isWordChar(graphemeAt(idx))
+  const isPunct = (idx: number): boolean => isVimPunctuation(graphemeAt(idx))
+
+  let startIdx = graphemeIdx
+  let endIdx = graphemeIdx
+
+  if (isWord(graphemeIdx)) {
+    while (startIdx > 0 && isWord(startIdx - 1)) startIdx--
+    while (endIdx < graphemes.length && isWord(endIdx)) endIdx++
+  } else if (isWs(graphemeIdx)) {
+    while (startIdx > 0 && isWs(startIdx - 1)) startIdx--
+    while (endIdx < graphemes.length && isWs(endIdx)) endIdx++
+    return { start: offsetAt(startIdx), end: offsetAt(endIdx) }
+  } else if (isPunct(graphemeIdx)) {
+    while (startIdx > 0 && isPunct(startIdx - 1)) startIdx--
+    while (endIdx < graphemes.length && isPunct(endIdx)) endIdx++
+  }
+
+  if (!isInner) {
+    // Include surrounding whitespace
+    if (endIdx < graphemes.length && isWs(endIdx)) {
+      while (endIdx < graphemes.length && isWs(endIdx)) endIdx++
+    } else if (startIdx > 0 && isWs(startIdx - 1)) {
+      while (startIdx > 0 && isWs(startIdx - 1)) startIdx--
+    }
+  }
+
+  return { start: offsetAt(startIdx), end: offsetAt(endIdx) }
+}
+
+function findQuoteObject(
+  text: string,
+  offset: number,
+  quote: string,
+  isInner: boolean,
+): TextObjectRange {
+  const lineStart = text.lastIndexOf('\n', offset - 1) + 1
+  const lineEnd = text.indexOf('\n', offset)
+  const effectiveEnd = lineEnd === -1 ? text.length : lineEnd
+  const line = text.slice(lineStart, effectiveEnd)
+  const posInLine = offset - lineStart
+
+  const positions: number[] = []
+  for (let i = 0; i < line.length; i++) {
+    if (line[i] === quote) positions.push(i)
+  }
+
+  // Pair quotes correctly: 0-1, 2-3, 4-5, etc.
+  for (let i = 0; i < positions.length - 1; i += 2) {
+    const qs = positions[i]!
+    const qe = positions[i + 1]!
+    if (qs <= posInLine && posInLine <= qe) {
+      return isInner
+        ? { start: lineStart + qs + 1, end: lineStart + qe }
+        : { start: lineStart + qs, end: lineStart + qe + 1 }
+    }
+  }
+
+  return null
+}
+
+function findBracketObject(
+  text: string,
+  offset: number,
+  open: string,
+  close: string,
+  isInner: boolean,
+): TextObjectRange {
+  let depth = 0
+  let start = -1
+
+  for (let i = offset; i >= 0; i--) {
+    if (text[i] === close && i !== offset) depth++
+    else if (text[i] === open) {
+      if (depth === 0) {
+        start = i
+        break
+      }
+      depth--
+    }
+  }
+  if (start === -1) return null
+
+  depth = 0
+  let end = -1
+  for (let i = start + 1; i < text.length; i++) {
+    if (text[i] === open) depth++
+    else if (text[i] === close) {
+      if (depth === 0) {
+        end = i
+        break
+      }
+      depth--
+    }
+  }
+  if (end === -1) return null
+
+  return isInner ? { start: start + 1, end } : { start, end: end + 1 }
+}