clint: remove CheckAltTokens()

- These "alternative tokens" keywords are for C++, not C.
- The check sometimes has false positives, e.g. `compl` is a variable
  name in edit.c

src/clint.py

@@ -234,38 +234,6 @@ _ERROR_CATEGORIES = [
 # All entries here should start with a '-' or '+', as in the --filter= flag.
 _DEFAULT_FILTERS = ['-build/include_alpha']
 
-# We used to check for high-bit characters, but after much discussion we
-# decided those were OK, as long as they were in UTF-8 and didn't represent
-# hard-coded international strings, which belong in a separate i18n file.
-
-# Alternative tokens and their replacements.  For full list, see section 2.5
-# Alternative tokens [lex.digraph] in the C++ standard.
-#
-# Digraphs (such as '%:') are not included here since it's a mess to
-# match those on a word boundary.
-_ALT_TOKEN_REPLACEMENT = {
-    'and': '&&',
-    'bitor': '|',
-    'or': '||',
-    'xor': '^',
-    'compl': '~',
-    'bitand': '&',
-    'and_eq': '&=',
-    'or_eq': '|=',
-    'xor_eq': '^=',
-    'not': '!',
-    'not_eq': '!='
-}
-
-# Compile regular expression that matches all the above keywords.  The "[ =()]"
-# bit is meant to avoid matching these keywords outside of boolean expressions.
-#
-# False positives include C-style multi-line comments and multi-line strings
-# but those have always been troublesome for cpplint.
-_ALT_TOKEN_REPLACEMENT_PATTERN = re.compile(
-    r'[ =()](' + ('|'.join(_ALT_TOKEN_REPLACEMENT.keys())) + r')(?=[ (]|$)')
-
-
 # These constants define types of headers for use with
 # _IncludeState.CheckNextIncludeOrder().
 _C_SYS_HEADER = 1
@@ -2868,38 +2836,6 @@ def CheckEmptyBlockBody(filename, clean_lines, linenum, error):
                       'Empty loop bodies should use {} or continue')
 
 
-def CheckAltTokens(filename, clean_lines, linenum, error):
-    """Check alternative keywords being used in boolean expressions.
-
-    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]
-
-    # Avoid preprocessor lines
-    if Match(r'^\s*#', line):
-        return
-
-    # Last ditch effort to avoid multi-line comments.  This will not help
-    # if the comment started before the current line or ended after the
-    # current line, but it catches most of the false positives.  At least,
-    # it provides a way to workaround this warning for people who use
-    # multi-line comments in preprocessor macros.
-    #
-    # TODO(unknown): remove this once cpplint has better support for
-    # multi-line comments.
-    if line.find('/*') >= 0 or line.find('*/') >= 0:
-        return
-
-    for match in _ALT_TOKEN_REPLACEMENT_PATTERN.finditer(line):
-        error(filename, linenum, 'readability/alt_tokens', 2,
-              'Use operator %s instead of %s' % (
-                  _ALT_TOKEN_REPLACEMENT[match.group(1)], match.group(1)))
-
-
 def GetLineWidth(line):
     """Determines the width of the line in column positions.
 
@@ -3023,7 +2959,6 @@ def CheckStyle(filename, clean_lines, linenum, file_extension, nesting_state,
     CheckBraces(filename, clean_lines, linenum, error)
     CheckEmptyBlockBody(filename, clean_lines, linenum, error)
     CheckSpacing(filename, clean_lines, linenum, nesting_state, error)
-    CheckAltTokens(filename, clean_lines, linenum, error)
 
 
 _RE_PATTERN_INCLUDE_NEW_STYLE = re.compile(r'#include +"[^/]+\.h"')