Function isInsideParenExpr

packages/queryLanguage/src/tokens.ts:424–433

* Checks if the parser stack indicates we're currently inside a ParenExpr.

(input: InputStream, stack: Stack)

 * Checks if the parser stack indicates we're currently inside a ParenExpr.
 */
function isInsideParenExpr(input: InputStream, stack: Stack): boolean {
    // First try the standard parser state check
    if (stack.canShift(closeParen)) {
        return true;
    }

    // If that fails, use a heuristic: look backwards for unmatched '('
    // This handles cases where the parser needs to reduce before shifting closeParen
    return hasUnmatchedOpenParen(input);
}

/**
 * External tokenizer for '(' - emits openParen only if there's a balanced ')'.