Mojo: add support for {double,float}.{INFINITY,NEGATIVE_INFINITY,NAN}

mojo/public/tools/bindings/pylib/mojom/parse/lexer.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import imp
 import os.path
 import sys
 
 def _GetDirAbove(dirname):
   """Returns the directory "above" this file containing |dirname| (which must
@@ skipping 127 matching lines @@
   # string literals (K&R2: A.2.6)
   string_char = r"""([^"\\\n]|"""+escape_sequence+')'
   string_literal = '"'+string_char+'*"'
   bad_string_literal = '"'+string_char+'*'+bad_escape+string_char+'*"'
 
   # floating constants (K&R2: A.2.5.3)
   exponent_part = r"""([eE][-+]?[0-9]+)"""
   fractional_constant = r"""([0-9]*\.[0-9]+)|([0-9]+\.)"""
   floating_constant = \
       '(((('+fractional_constant+')'+ \
-      exponent_part+'?)|([0-9]+'+exponent_part+')))'
+      exponent_part+'?)|([0-9]+'+exponent_part+'))|[-+]?Inf|NaN)'

[viettrungluu, 2014/08/14 22:32:25]

Currently, for numbers, we use unary minus (and plus), so that "- 123" is
allowed (instead of only allowing "-123").

(I have mixed feelings about allowing the space, but it's consistent with most
languages.)

We should probably re-use that for +/- infinity. (Also, this might have the side
effect of allowing "- -Inf" and maybe even "--Inf", etc.)

 
   # Ordinals
   ordinal = r'@[0-9]+'
   missing_ordinal_value = r'@'
   # Don't allow ordinal values in octal (even invalid octal, like 09) or
   # hexadecimal.
   octal_or_hex_ordinal_disallowed = r'@((0[0-9]+)|('+hex_prefix+hex_digits+'))'
 
   ##
   ## Rules for the normal state
@@ skipping 82 matching lines @@
     return t
 
   # Ignore C and C++ style comments
   def t_COMMENT(self, t):
     r'(/\*(.|\n)*?\*/)|(//.*(\n[ \t]*//.*)*)'
     t.lexer.lineno += t.value.count("\n")
 
   def t_error(self, t):
     msg = "Illegal character %s" % repr(t.value[0])
     self._error(msg, t)