Function scanTopLevelQuotes

src/shared/parse-command.ts:201–395

* Single shared state-machine walk used by both `findUnterminatedQuote` and * `maskTopLevelQuotes`. Walks `command` left-to-right, identifies every * top-level quoted region (outside any other quote and outside `#` comments), * and returns the list of spans together with an unterminated-quote des

(command: string)

 * - `heredoc`      <<WORD...WORD
 */
function scanTopLevelQuotes(command: string): ScanResult {
	const spans: QuoteSpan[] = []
	let i = 0

	while (i < command.length) {
		const char = command[i]

		// Outside any quoted region: handle backslash, comments, and quote openers.
		if (char === "\\") {
			// Backslash escapes the next character; a quote after it is literal.
			i += 2
			continue
		}

		if (char === "#" && (i === 0 || /\s/.test(command[i - 1]))) {
			// Comment: skip to end of line. Quotes inside are not shell quoting.
			while (i < command.length && command[i] !== "\n" && command[i] !== "\r") {
				i++
			}
			continue
		}

		// Herestring (<<<): single-line stdin redirect -- no body or terminator.
		if (char === "<" && command[i + 1] === "<" && command[i + 2] === "<") {
			i += 3
			continue
		}

		// Heredoc opener: <<[-]? followed by an optional-quoted delimiter word.
		if (char === "<" && command[i + 1] === "<") {
			const start = i
			i += 2 // skip <<
			const stripTabs = command[i] === "-"
			if (stripTabs) i++
			// Skip horizontal whitespace between << and the delimiter word.
			while (i < command.length && (command[i] === " " || command[i] === "\t")) {
				i++
			}
			const { delimiter, endIndex } = parseHeredocDelimiter(command, i)
			i = endIndex
			// Advance past the remainder of the opener line.
			while (i < command.length && command[i] !== "\n") i++
			if (i < command.length) i++ // consume newline
			if (delimiter.length > 0) {
				let found = false
				while (i < command.length) {
					const lineStart = i
					while (i < command.length && command[i] !== "\n" && command[i] !== "\r") {
						i++
					}
					// Strip leading tabs only for <<- heredocs.
					const rawLine = command.slice(lineStart, i)
					const line = stripTabs ? rawLine.replace(/^\t*/, "") : rawLine
					// Do NOT advance past the terminator's newline -- leave it as a
					// separator for any command that follows the heredoc.
					if (line === delimiter) {
						found = true
						break