Mojo: Add basic IDL parser.

mojo/public/bindings/parser/mojo_parser.py

Index: mojo/public/bindings/parser/mojo_parser.py
diff --git a/mojo/public/bindings/parser/mojo_parser.py b/mojo/public/bindings/parser/mojo_parser.py
new file mode 100755
index 0000000000000000000000000000000000000000..a967fbcb528b7572dab62680b4d5764642efe9d5
--- /dev/null
+++ b/mojo/public/bindings/parser/mojo_parser.py
@@ -0,0 +1,232 @@
+#!/usr/bin/env python
+# Copyright 2013 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.
+
+"""Generates a syntax tree from a Mojo IDL file."""
+
+
+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 import lex
+  from ply import yacc
+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 import lex
+  from ply import yacc
+
+
+def ListFromConcat(*items):
+  """Generate list by concatenating inputs"""
+  itemsout = []
+  for item in items:
+    if item is None:
+      continue
+    if type(item) is not type([]):
+      itemsout.append(item)
+    else:
+      itemsout.extend(item)
+
+  return itemsout
+
+
+class Lexer(object):
+
+  # This field is required by lex to specify the complete list of valid tokens.
+  tokens = (
+    'NAME',
+    'NUMBER',
+
+    'ARRAY',
+    'ORDINAL',
+
+    'MODULE',
+    'STRUCT',
+    'INTERFACE',
+    'VOID',
+
+    'LCURLY',
+    'RCURLY',
+    'LPAREN',
+    'RPAREN',
+    'LBRACKET',
+    'RBRACKET',
+    'COMMA',
+    'SEMICOLON',
+    'EQUALS',
+  )
+
+  t_LCURLY     = r'{'
+  t_RCURLY     = r'}'
+  t_LPAREN     = r'\('
+  t_RPAREN     = r'\)'
+  t_LBRACKET   = r'\['
+  t_RBRACKET   = r'\]'
+  t_COMMA      = r','
+  t_SEMICOLON  = r';'
+  t_EQUALS     = r'='
+  t_NAME       = r'[a-zA-Z_][a-zA-Z0-9_]*'
+  t_ARRAY      = r'[a-zA-Z_][a-zA-Z0-9_]*\[\]'
+  t_NUMBER     = r'\d+'
+  t_ORDINAL    = r'@[0-9]*'
+
+  def t_MODULE(self, t):
+    r'module'
+    return t
+
+  def t_STRUCT(self, t):
+    r'struct'
+    return t
+
+  def t_INTERFACE(self, t):
+    r'interface'
+    return t
+
+  def t_VOID(self, t):
+    r'void'
+    return t
+
+  # Ignore C and C++ style comments
+  def t_COMMENT(self, t):
+    r'(/\*(.|\n)*?\*/)|(//.*(\n[ \t]*//.*)*)'
+    pass
+
+  # Ignored characters
+  t_ignore = " \t"
+
+  def t_newline(self, t):
+    r'\n+'
+    t.lexer.lineno += t.value.count("\n")
+
+  def t_error(self, t):
+    print("Illegal character '%s'" % t.value[0])
+    t.lexer.skip(1)
+
+
+class Parser(object):
+
+  def __init__(self, lexer):
+    self.tokens = lexer.tokens
+
+  def p_module(self, p):
+    """module : MODULE NAME LCURLY definitions RCURLY"""
+    p[0] = ('MODULE', p[2], p[4])
+
+  def p_definitions(self, p):
+    """definitions : definition definitions
+                   |"""
+    if len(p) > 1:
+      p[0] = ListFromConcat(p[1], p[2])
+
+  def p_definition(self, p):
+    """definition : struct
+                  | interface"""
+    p[0] = p[1]
+
+  def p_attribute_section(self, p):
+    """attribute_section : LBRACKET attributes RBRACKET
+                         | """
+    if len(p) > 3:
+      p[0] = p[2]
+
+  def p_attributes(self, p):
+    """attributes : attribute
+                  | attribute COMMA attributes
+                  | """
+    if len(p) == 2:
+      p[0] = ListFromConcat(p[1])
+    elif len(p) > 3:
+      p[0] = ListFromConcat(p[1], p[3])
+
+  def p_attribute(self, p):
+    """attribute : NAME EQUALS NUMBER"""
+    p[0] = ('ATTRIBUTE', p[1], p[3])
+
+  def p_struct(self, p):
+    """struct : attribute_section STRUCT NAME LCURLY fields RCURLY SEMICOLON"""
+    p[0] = ('STRUCT', p[3], p[1], p[5])
+
+  def p_fields(self, p):
+    """fields : field fields
+              |"""
+    if len(p) > 1:
+      p[0] = ListFromConcat(p[1], p[2])
+
+  def p_field(self, p):
+    """field : typename NAME ordinal SEMICOLON"""
+    p[0] = ('FIELD', p[1], p[2], p[3])
+
+  def p_interface(self, p):
+    """interface : INTERFACE NAME LCURLY methods RCURLY SEMICOLON"""
+    p[0] = ('INTERFACE', p[2], p[4])
+
+  def p_methods(self, p):
+    """methods : method methods
+               | """
+    if len(p) > 1:
+      p[0] = ListFromConcat(p[1], p[2])
+
+  def p_method(self, p):
+    """method : VOID NAME LPAREN parameters RPAREN ordinal SEMICOLON"""
+    p[0] = ('METHOD', p[2], p[4], p[6])
+
+  def p_parameters(self, p):
+    """parameters : parameter
+                  | parameter COMMA parameters
+                  | """
+    if len(p) == 2:
+      p[0] = p[1]
+    elif len(p) > 3:
+      p[0] = ListFromConcat(p[1], p[3])
+
+  def p_parameter(self, p):
+    """parameter : typename NAME ordinal"""
+    p[0] = ('PARAM', p[1], p[2], p[3])
+
+  def p_typename(self, p):
+    """typename : NAME
+                | ARRAY"""
+    p[0] = p[1]
+
+  def p_ordinal(self, p):
+    """ordinal : ORDINAL
+               | """
+    if len(p) > 1:
+      p[0] = p[1]
+
+  def p_error(self, e):
+    print('error: %s'%e)
+
+
+def Parse(filename):
+  lexer = Lexer()
+  parser = Parser(lexer)
+
+  lex.lex(object=lexer)
+  yacc.yacc(module=parser, debug=0, write_tables=0)
+
+  tree = yacc.parse(open(filename).read())
+  return tree
+
+
+def Main():
+  if len(sys.argv) < 2:
+    print("usage: %s filename" % (sys.argv[0]))
+    sys.exit(1)
+  tree = Parse(filename=sys.argv[1])
+  print(tree)
+
+
+if __name__ == '__main__':
+  Main()