Function CheckOperatorSpacing

tools/cpplint.py:4351–4467

Checks for horizontal spacing around operators. Args: filename: The name of the current file. clean_lines: A CleansedLines instance containing the file. linenum: The number of the line to check. error: The function to call with any errors found.

(filename, clean_lines, linenum, error)

def CheckOperatorSpacing(filename, clean_lines, linenum, error):
    """Checks for horizontal spacing around operators.

    Args:
      filename: The name of the current file.
      clean_lines: A CleansedLines instance containing the file.
      linenum: The number of the line to check.
      error: The function to call with any errors found.
    """
    line = clean_lines.elided[linenum]

    # Don't try to do spacing checks for operator methods.  Do this by
    # replacing the troublesome characters with something else,
    # preserving column position for all other characters.
    #
    # The replacement is done repeatedly to avoid false positives from
    # operators that call operators.
    while True:
        match = re.match(r"^(.*\boperator\b)(\S+)(\s*\(.*)$", line)
        if match:
            line = match.group(1) + ("_" * len(match.group(2))) + match.group(3)
        else:
            break

    # We allow no-spaces around = within an if: "if ( (a=Foo()) == 0 )".
    # Otherwise not.  Note we only check for non-spaces on *both* sides;
    # sometimes people put non-spaces on one side when aligning ='s among
    # many lines (not that this is behavior that I approve of...)
    if (
        (re.search(r"[\w.]=", line) or re.search(r"=[\w.]", line))
        and not re.search(r"\b(if|while|for) ", line)
        # Operators taken from [lex.operators] in C++11 standard.
        and not re.search(r"(>=|<=|==|!=|&=|\^=|\|=|\+=|\*=|\/=|\%=)", line)
        and not re.search(r"operator=", line)
    ):
        error(filename, linenum, "whitespace/operators", 4, "Missing spaces around =")

    # It's ok not to have spaces around binary operators like + - * /, but if
    # there's too little whitespace, we get concerned.  It's hard to tell,
    # though, so we punt on this one for now.  TODO(google).

    # You should always have whitespace around binary operators.
    #
    # Check <= and >= first to avoid false positives with < and >, then
    # check non-include lines for spacing around < and >.
    #
    # If the operator is followed by a comma, assume it's be used in a
    # macro context and don't do any checks.  This avoids false
    # positives.
    #
    # Note that && is not included here.  This is because there are too
    # many false positives due to RValue references.
    match = re.search(r"[^<>=!\s](==|!=|<=|>=|\|\|)[^<>=!\s,;\)]", line)
    if match:
        # TODO(google): support alternate operators
        error(
            filename, linenum, "whitespace/operators", 3, f"Missing spaces around {match.group(1)}"
        )