Add support for using expressions as enum values.

mojo/public/bindings/parse/mojo_lexer.py

+# PLY based Lexer class, based on pycparser by Eli Bendersky.
+#
+# Copyright (C) 2008-2013, Eli Bendersky
+# License: BSD
+
+import re
+import sys
+import os.path
+
+# Try to load the ply module, if not, then assume it is in the third_party
+# directory.
+try:
+  # Disable lint check which fails to find the ply module.
+  # pylint: disable=F0401
+  from ply.lex import TOKEN
+except ImportError:
+  module_path, module_name = os.path.split(__file__)
+  third_party = os.path.join(
+      module_path, os.pardir, os.pardir, os.pardir, os.pardir, 'third_party')
+  sys.path.append(third_party)
+  # pylint: disable=F0401
+  from ply.lex import TOKEN
+
+
+class Lexer(object):
+  ######################--   PRIVATE   --######################
+
+  ##
+  ## Internal auxiliary methods
+  ##
+  def _error(self, msg, token):
+    print('%s at line %d' % (msg, token.lineno))
+    self.lexer.skip(1)
+
+  ##
+  ## Reserved keywords
+  ##
+  keywords = (
+    'HANDLE',
+    'DATA_PIPE_CONSUMER',
+    'DATA_PIPE_PRODUCER',
+    'MESSAGE_PIPE',
+
+    'MODULE',
+    'STRUCT',
+    'INTERFACE',
+    'ENUM',
+    'VOID',
+  )
+
+  keyword_map = {}
+  for keyword in keywords:
+    keyword_map[keyword.lower()] = keyword
+
+  ##
+  ## All the tokens recognized by the lexer
+  ##
+  tokens = keywords + (
+    # Identifiers
+    'NAME',
+
+    # constants
+    'ORDINAL',
+    'INT_CONST_DEC', 'INT_CONST_OCT', 'INT_CONST_HEX',
+    'FLOAT_CONST', 'HEX_FLOAT_CONST',
+    'CHAR_CONST',
+    'WCHAR_CONST',
+
+    # String literals
+    'STRING_LITERAL',
+    'WSTRING_LITERAL',
+
+    # Operators
+    'PLUS', 'MINUS', 'TIMES', 'DIVIDE', 'MOD',
+    'OR', 'AND', 'NOT', 'XOR', 'LSHIFT', 'RSHIFT',
+    'LOR', 'LAND', 'LNOT',
+    'LT', 'LE', 'GT', 'GE', 'EQ', 'NE',
+
+    # Assignment
+    'EQUALS',
+
+    # Conditional operator (?)
+    'CONDOP',
+
+    # Delimeters
+    'LPAREN', 'RPAREN',         # ( )
+    'LBRACKET', 'RBRACKET',     # [ ]
+    'LBRACE', 'RBRACE',         # { }
+    'SEMI', 'COLON',            # ; :
+    'COMMA',                    # .
+  )
+
+  ##
+  ## Regexes for use in tokens
+  ##
+  ##
+
+  # valid C identifiers (K&R2: A.2.3), plus '$' (supported by some compilers)
+  identifier = r'[a-zA-Z_$][0-9a-zA-Z_$]*'
+
+  hex_prefix = '0[xX]'
+  hex_digits = '[0-9a-fA-F]+'
+
+  # integer constants (K&R2: A.2.5.1)
+  integer_suffix_opt = \
+      r'(([uU]ll)|([uU]LL)|(ll[uU]?)|(LL[uU]?)|([uU][lL])|([lL][uU]?)|[uU])?'
+  decimal_constant = \
+      '(0'+integer_suffix_opt+')|([1-9][0-9]*'+integer_suffix_opt+')'
+  octal_constant = '0[0-7]*'+integer_suffix_opt
+  hex_constant = hex_prefix+hex_digits+integer_suffix_opt
+
+  bad_octal_constant = '0[0-7]*[89]'
+
+  # character constants (K&R2: A.2.5.2)
+  # Note: a-zA-Z and '.-~^_!=&;,' are allowed as escape chars to support #line
+  # directives with Windows paths as filenames (..\..\dir\file)
+  # For the same reason, decimal_escape allows all digit sequences. We want to
+  # parse all correct code, even if it means to sometimes parse incorrect
+  # code.
+  #
+  simple_escape = r"""([a-zA-Z._~!=&\^\-\\?'"])"""
+  decimal_escape = r"""(\d+)"""
+  hex_escape = r"""(x[0-9a-fA-F]+)"""
+  bad_escape = r"""([\\][^a-zA-Z._~^!=&\^\-\\?'"x0-7])"""
+
+  escape_sequence = \
+      r"""(\\("""+simple_escape+'|'+decimal_escape+'|'+hex_escape+'))'
+  cconst_char = r"""([^'\\\n]|"""+escape_sequence+')'
+  char_const = "'"+cconst_char+"'"
+  wchar_const = 'L'+char_const
+  unmatched_quote = "('"+cconst_char+"*\\n)|('"+cconst_char+"*$)"
+  bad_char_const = \
+      r"""('"""+cconst_char+"""[^'\n]+')|('')|('"""+ \
+      bad_escape+r"""[^'\n]*')"""
+
+  # string literals (K&R2: A.2.6)
+  string_char = r"""([^"\\\n]|"""+escape_sequence+')'
+  string_literal = '"'+string_char+'*"'
+  wstring_literal = 'L'+string_literal
+  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+'))[FfLl]?)'
+  binary_exponent_part = r'''([pP][+-]?[0-9]+)'''
+  hex_fractional_constant = \
+      '((('+hex_digits+r""")?\."""+hex_digits+')|('+hex_digits+r"""\.))"""
+  hex_floating_constant = \
+      '('+hex_prefix+'('+hex_digits+'|'+hex_fractional_constant+')'+ \
+      binary_exponent_part+'[FfLl]?)'
+
+  ##
+  ## Rules for the normal state
+  ##
+  t_ignore = ' \t'
+
+  # Newlines
+  def t_NEWLINE(self, t):
+    r'\n+'
+    t.lexer.lineno += t.value.count("\n")
+
+  # Operators
+  t_PLUS              = r'\+'
+  t_MINUS             = r'-'
+  t_TIMES             = r'\*'
+  t_DIVIDE            = r'/'
+  t_MOD               = r'%'
+  t_OR                = r'\|'
+  t_AND               = r'&'
+  t_NOT               = r'~'
+  t_XOR               = r'\^'
+  t_LSHIFT            = r'<<'
+  t_RSHIFT            = r'>>'
+  t_LOR               = r'\|\|'
+  t_LAND              = r'&&'
+  t_LNOT              = r'!'
+  t_LT                = r'<'
+  t_GT                = r'>'
+  t_LE                = r'<='
+  t_GE                = r'>='
+  t_EQ                = r'=='
+  t_NE                = r'!='
+
+  # =
+  t_EQUALS            = r'='
+
+  # ?
+  t_CONDOP            = r'\?'
+
+  # Delimeters
+  t_LPAREN            = r'\('
+  t_RPAREN            = r'\)'
+  t_LBRACKET          = r'\['
+  t_RBRACKET          = r'\]'
+  t_LBRACE            = r'\{'
+  t_RBRACE            = r'\}'
+  t_COMMA             = r','
+  t_SEMI              = r';'
+  t_COLON             = r':'
+
+  t_STRING_LITERAL    = string_literal
+  t_ORDINAL           = r'@[0-9]*'
+
+  # The following floating and integer constants are defined as
+  # functions to impose a strict order (otherwise, decimal
+  # is placed before the others because its regex is longer,
+  # and this is bad)
+  #
+  @TOKEN(floating_constant)
+  def t_FLOAT_CONST(self, t):
+    return t
+
+  @TOKEN(hex_floating_constant)
+  def t_HEX_FLOAT_CONST(self, t):
+    return t
+
+  @TOKEN(hex_constant)
+  def t_INT_CONST_HEX(self, t):
+    return t
+
+  @TOKEN(bad_octal_constant)
+  def t_BAD_CONST_OCT(self, t):
+    msg = "Invalid octal constant"
+    self._error(msg, t)
+
+  @TOKEN(octal_constant)
+  def t_INT_CONST_OCT(self, t):
+    return t
+
+  @TOKEN(decimal_constant)
+  def t_INT_CONST_DEC(self, t):
+    return t
+
+  # Must come before bad_char_const, to prevent it from
+  # catching valid char constants as invalid
+  #
+  @TOKEN(char_const)
+  def t_CHAR_CONST(self, t):
+    return t
+
+  @TOKEN(wchar_const)
+  def t_WCHAR_CONST(self, t):
+    return t
+
+  @TOKEN(unmatched_quote)
+  def t_UNMATCHED_QUOTE(self, t):
+    msg = "Unmatched '"
+    self._error(msg, t)
+
+  @TOKEN(bad_char_const)
+  def t_BAD_CHAR_CONST(self, t):
+    msg = "Invalid char constant %s" % t.value
+    self._error(msg, t)
+
+  @TOKEN(wstring_literal)
+  def t_WSTRING_LITERAL(self, t):
+    return t
+
+  # unmatched string literals are caught by the preprocessor
+
+  @TOKEN(bad_string_literal)
+  def t_BAD_STRING_LITERAL(self, t):
+    msg = "String contains invalid escape code"
+    self._error(msg, t)
+
+  @TOKEN(identifier)
+  def t_NAME(self, t):
+    t.type = self.keyword_map.get(t.value, "NAME")
+    return t
+
+  # Ignore C and C++ style comments
+  def t_COMMENT(self, t):
+    r'(/\*(.|\n)*?\*/)|(//.*(\n[ \t]*//.*)*)'
+    pass
+
+  def t_error(self, t):
+    msg = 'Illegal character %s' % repr(t.value[0])
+    self._error(msg, t)