Function FindStartOfExpressionInLine

cpplint.py:2317–2394

Find position at the matching start of current expression. This is almost the reverse of FindEndOfExpressionInLine, but note that the input position and returned position differs by 1. Args: line: a CleansedLines line. endpos: start searching at this position. stack:

(line, endpos, stack)

def FindStartOfExpressionInLine(line, endpos, stack):
    """Find position at the matching start of current expression.

    This is almost the reverse of FindEndOfExpressionInLine, but note
    that the input position and returned position differs by 1.

    Args:
      line: a CleansedLines line.
      endpos: start searching at this position.
      stack: nesting stack at endpos.

    Returns:
      On finding matching start: (index at matching start, None)
      On finding an unclosed expression: (-1, None)
      Otherwise: (-1, new stack at beginning of this line)
    """
    i = endpos
    while i >= 0:
        char = line[i]
        if char in ")]}":
            # Found end of expression, push to expression stack
            stack.append(char)
        elif char == ">":
            # Found potential end of template argument list.
            #
            # Ignore it if it's a "->" or ">=" or "operator>"
            if i > 0 and (
                line[i - 1] == "-"
                or re.match(r"\s>=\s", line[i - 1 :])
                or re.search(r"\boperator\s*$", line[0:i])
            ):
                i -= 1
            else:
                stack.append(">")
        elif char == "<":
            # Found potential start of template argument list
            if i > 0 and line[i - 1] == "<":
                # Left shift operator
                i -= 1
            else:
                # If there is a matching '>', we can pop the expression stack.
                # Otherwise, ignore this '<' since it must be an operator.
                if stack and stack[-1] == ">":
                    stack.pop()
                    if not stack:
                        return (i, None)
        elif char in "([{":
            # Found start of expression.
            #
            # If there are any unmatched '>' on the stack, they must be
            # operators.  Remove those.
            while stack and stack[-1] == ">":
                stack.pop()
            if not stack:
                return (-1, None)
            if (
                (char == "(" and stack[-1] == ")")
                or (char == "[" and stack[-1] == "]")