three files from the p2c cvs tree. the message here indicates the

revision number the p2c cvs tree.

COPYRIGHT: 1.1
ast.py: 1.3
transformer.py: 1.11

1 files changed, 1204 insertions, 0 deletions

diff --git a/Lib/compiler/transformer.py b/Lib/compiler/transformer.py
new file mode 100644
index 0000000..9200f7a
--- /dev/null
+++ b/Lib/compiler/transformer.py
@@ -0,0 +1,1204 @@
+# Copyright 1997-1998 Greg Stein and Bill Tutt
+#
+# transformer.py -- transforms Python parse trees
+#
+# Takes an input parse tree and transforms it into a higher-level parse
+# tree that is a bit more amenable to code generation. Essentially, it
+# simply introduces some additional semantics.
+#
+# Written by Greg Stein (gstein@lyra.org)
+#        and Bill Tutt (rassilon@lima.mudlib.org)
+# February 1997.
+#
+# Support for Node subclasses written by
+#  Jeremy Hylton (jeremy@cnri.reston.va.us)
+#
+# The output tree has the following nodes:
+#
+# Source Python line #'s appear at the end of each of all of these nodes
+# If a line # doesn't apply, there will be a None instead.
+#
+# module:     doc, node
+# stmt:       [ node1, ..., nodeN ]
+# function:   name, argnames, defaults, flags, doc, codeNode
+# lambda:     argnames, defaults, flags, codeNode
+# classdef:   name, bases, doc, codeNode
+# pass:
+# break:
+# continue:
+# for:        assignNode, listNode, bodyNode, elseNode
+# while:      testNode, bodyNode, elseNode
+# if:         [ (testNode, suiteNode), ... ], elseNode
+# exec:       expr1Node, expr2Node, expr3Node
+# from:       modname, [ name1, ..., nameN ]
+# import:     [ name1, ..., nameN ]
+# raise:      expr1Node, expr2Node, expr3Node
+# tryfinally: trySuiteNode, finSuiteNode
+# tryexcept:  trySuiteNode, [ (exprNode, assgnNode, suiteNode), ... ], elseNode
+# return:     valueNode
+# const:      value
+# print:      [ node1, ..., nodeN ]
+# printnl:    [ node1, ..., nodeN ]
+# discard:    exprNode
+# assign:     [ node1, ..., nodeN ], exprNode
+# ass_tuple:  [ node1, ..., nodeN ]
+# ass_list:   [ node1, ..., nodeN ]
+# ass_name:   name, flags
+# ass_attr:   exprNode, attrname, flags
+# list:       [ node1, ..., nodeN ]
+# dict:       [ (key1, val1), ..., (keyN, valN) ]
+# not:        exprNode
+# compare:    exprNode, [ (op, node), ..., (op, node) ]
+# name:       name
+# global:     [ name1, ..., nameN ]
+# backquote:  node
+# getattr:    exprNode, attrname
+# call_func:  node, [ arg1, ..., argN ]
+# keyword:    name, exprNode
+# subscript:  exprNode, flags, [ sub1, ..., subN ]
+# ellipsis:
+# sliceobj:   [ node1, ..., nodeN ]
+# slice:      exprNode, flags, lowerNode, upperNode
+# assert:     expr1, expr2
+#
+# Compiled as "binary" ops:
+# tuple:      [ node1, ..., nodeN ]
+# or:         [ node1, ..., nodeN ]
+# and:        [ node1, ..., nodeN ]
+# bitor:      [ node1, ..., nodeN ]
+# bitxor:     [ node1, ..., nodeN ]
+# bitand:     [ node1, ..., nodeN ]
+#
+# Operations easily evaluateable on constants:
+# <<:         exprNode, shiftNode
+# >>:         exprNode, shiftNode
+# +:          leftNode, rightNode
+# -:          leftNode, rightNode
+# *:          leftNode, rightNode
+# /:          leftNode, rightNode
+# %:          leftNode, rightNode
+# power:      leftNode, rightNode
+# unary+:     node
+# unary-:     node
+# invert:     node
+#
+
+"""Parse tree transformation module.
+
+Exposes the Transformer class with a number of methods for returning a
+"cleansed AST" instead of the parse tree that the parser exposes.
+"""
+
+import ast
+import parser
+import symbol
+import token
+import string
+
+import pprint
+
+error = 'walker.error'
+
+# code flags
+CO_VARARGS = 1
+CO_VARKEYWORDS = 2
+
+# operation flags
+OP_ASSIGN = 'OP_ASSIGN'
+OP_DELETE = 'OP_DELETE'
+OP_APPLY = 'OP_APPLY'
+
+def asList(nodes):
+  l = []
+  for item in nodes:
+    if hasattr(item, "asList"):
+      l.append(item.asList())
+    else:
+      if type(item) is type( (None, None) ):
+        l.append(tuple(asList(item)))
+      elif type(item) is type( [] ):
+        l.append(asList(item))
+      else:
+        l.append(item)
+  return l
+
+def Node(*args):
+  kind = args[0]
+  if ast.nodes.has_key(kind):
+    try:
+      return apply(ast.nodes[kind], args[1:])
+    except TypeError:
+      print ast.nodes[kind], len(args), args
+      raise
+  else:
+    raise error, "Can't find appropriate Node type."
+    #return apply(ast.Node, args)
+
+class Transformer:
+  """Utility object for transforming Python parse trees.
+
+  Exposes the following methods:
+    tree = transform(ast_tree)
+    tree = parsesuite(text)
+    tree = parseexpr(text)
+    tree = parsefile(fileob | filename)
+  """
+
+  def __init__(self):
+    self._dispatch = { }
+    for value, name in symbol.sym_name.items():
+      if hasattr(self, name):
+        self._dispatch[value] = getattr(self, name)
+
+  def transform(self, tree):
+    """Transform an AST into a modified parse tree."""
+    if type(tree) != type(()) and type(tree) != type([]):
+      tree = parser.ast2tuple(tree,1)
+    return self.compile_node(tree)
+
+  def parsesuite(self, text):
+    """Return a modified parse tree for the given suite text."""
+    # Hack for handling non-native line endings on non-DOS like OSs.
+    text = string.replace(text, '\x0d', '')
+    return self.transform(parser.suite(text))
+
+  def parseexpr(self, text):
+    """Return a modified parse tree for the given expression text."""
+    return self.transform(parser.expr(text))
+
+  def parsefile(self, file):
+    """Return a modified parse tree for the contents of the given file."""
+    if type(file) == type(''):
+      file = open(file)
+    return self.parsesuite(file.read())
+
+  # --------------------------------------------------------------
+  #
+  # PRIVATE METHODS
+  #
+
+  def compile_node(self, node):
+    ### emit a line-number node?
+    n = node[0]
+    if n == symbol.single_input:
+      return self.single_input(node[1:])
+    if n == symbol.file_input:
+      return self.file_input(node[1:])
+    if n == symbol.eval_input:
+      return self.eval_input(node[1:])
+    if n == symbol.lambdef:
+      return self.lambdef(node[1:])
+    if n == symbol.funcdef:
+      return self.funcdef(node[1:])
+    if n == symbol.classdef:
+      return self.classdef(node[1:])
+
+    raise error, ('unexpected node type', n)
+
+  def single_input(self, node):
+    ### do we want to do anything about being "interactive" ?
+
+    # NEWLINE | simple_stmt | compound_stmt NEWLINE
+    n = node[0][0]
+    if n != token.NEWLINE:
+      return self.com_stmt(node[0])
+
+    return Node('pass')
+
+  def file_input(self, nodelist):
+    doc = self.get_docstring(nodelist, symbol.file_input)
+    stmts = [ ]
+    for node in nodelist:
+      if node[0] != token.ENDMARKER and node[0] != token.NEWLINE:
+        self.com_append_stmt(stmts, node)
+    return Node('module', doc, Node('stmt', stmts))
+
+  def eval_input(self, nodelist):
+    # from the built-in function input()
+    ### is this sufficient?
+    return self.com_node(nodelist[0])
+
+  def funcdef(self, nodelist):
+    # funcdef: 'def' NAME parameters ':' suite
+    # parameters: '(' [varargslist] ')'
+
+    lineno = nodelist[1][2]
+    name   = nodelist[1][1]
+    args   = nodelist[2][2]
+
+    if args[0] == symbol.varargslist:
+      names, defaults, flags = self.com_arglist(args[1:])
+    else:
+      names = defaults = ()
+      flags = 0
+    doc = self.get_docstring(nodelist[4])
+
+    # code for function
+    code = self.com_node(nodelist[4])
+
+    n = Node('function', name, names, defaults, flags, doc, code)
+    n.lineno = lineno
+    return n
+
+  def lambdef(self, nodelist):
+    # lambdef: 'lambda' [varargslist] ':' test
+    if nodelist[2][0] == symbol.varargslist:
+      names, defaults, flags = self.com_arglist(nodelist[2][1:])
+    else:
+      names = defaults = ()
+      flags = 0
+
+    # code for lambda
+    code = self.com_node(nodelist[-1])
+
+    n = Node('lambda', names, defaults, flags, code)
+    n.lineno = nodelist[1][2]
+    return n
+
+  def classdef(self, nodelist):
+    # classdef: 'class' NAME ['(' testlist ')'] ':' suite
+
+    name = nodelist[1][1]
+    doc = self.get_docstring(nodelist[-1])
+    if nodelist[2][0] == token.COLON:
+      bases = []
+    else:
+      bases = self.com_bases(nodelist[3])
+
+    # code for class
+    code = self.com_node(nodelist[-1])
+
+    n = Node('classdef', name, bases, doc, code)
+    n.lineno = nodelist[1][2]
+    return n
+
+  def stmt(self, nodelist):
+    return self.com_stmt(nodelist[0])
+
+  small_stmt = stmt
+  flow_stmt = stmt
+  compound_stmt = stmt
+
+  def simple_stmt(self, nodelist):
+    # small_stmt (';' small_stmt)* [';'] NEWLINE
+    stmts = [ ]
+    for i in range(0, len(nodelist), 2):
+      self.com_append_stmt(stmts, nodelist[i])
+    return Node('stmt', stmts)
+
+  def parameters(self, nodelist):
+    raise error
+
+  def varargslist(self, nodelist):
+    raise error
+
+  def fpdef(self, nodelist):
+    raise error
+
+  def fplist(self, nodelist):
+    raise error
+
+  def dotted_name(self, nodelist):
+    raise error
+
+  def comp_op(self, nodelist):
+    raise error
+
+  def trailer(self, nodelist):
+    raise error
+
+  def sliceop(self, nodelist):
+    raise error
+
+  def argument(self, nodelist):
+    raise error
+
+  # --------------------------------------------------------------
+  #
+  # STATEMENT NODES  (invoked by com_node())
+  #
+
+  def expr_stmt(self, nodelist):
+    # testlist ('=' testlist)*
+    exprNode = self.com_node(nodelist[-1])
+    if len(nodelist) == 1:
+      return Node('discard', exprNode)
+    nodes = [ ]
+    for i in range(0, len(nodelist) - 2, 2):
+      nodes.append(self.com_assign(nodelist[i], OP_ASSIGN))
+    n = Node('assign', nodes, exprNode)
+    n.lineno = nodelist[1][2]
+    return n
+
+  def print_stmt(self, nodelist):
+    # print: (test ',')* [test]
+    items = [ ]
+    for i in range(1, len(nodelist), 2):
+      items.append(self.com_node(nodelist[i]))
+    if nodelist[-1][0] == token.COMMA:
+      n = Node('print', items)
+      n.lineno = nodelist[0][2]
+      return n
+    n = Node('printnl', items)
+    n.lineno = nodelist[0][2]
+    return n
+
+  def del_stmt(self, nodelist):
+    return self.com_assign(nodelist[1], OP_DELETE)
+
+  def pass_stmt(self, nodelist):
+    # pass:
+    n = Node('pass')
+    n.lineno = nodelist[0][2]
+    return n
+
+  def break_stmt(self, nodelist):
+    # break:
+    n = Node('break')
+    n.lineno = nodelist[0][2]
+    return n
+
+  def continue_stmt(self, nodelist):
+    # continue
+    n = Node('continue')
+    n.lineno = nodelist[0][2]
+    return n
+
+  def return_stmt(self, nodelist):
+    # return: [testlist]
+    if len(nodelist) < 2:
+      n = Node('return', Node('const', None))
+      n.lineno = nodelist[0][2]
+      return n
+    n = Node('return', self.com_node(nodelist[1]))
+    n.lineno = nodelist[0][2]
+    return n
+
+  def raise_stmt(self, nodelist):
+    # raise: [test [',' test [',' test]]]
+    if len(nodelist) > 5:
+      expr3 = self.com_node(nodelist[5])
+    else:
+      expr3 = None
+    if len(nodelist) > 3:
+      expr2 = self.com_node(nodelist[3])
+    else:
+      expr2 = None
+    if len(nodelist) > 1:
+      expr1 = self.com_node(nodelist[1])
+    else:
+      expr1 = None
+    n = Node('raise', expr1, expr2, expr3)
+    n.lineno = nodelist[0][2]
+    return n
+
+  def import_stmt(self, nodelist):
+    # import: dotted_name (',' dotted_name)* |
+    # from: dotted_name 'import' ('*' | NAME (',' NAME)*)
+    names = [ ]
+    if nodelist[0][1][0] == 'f':
+      for i in range(3, len(nodelist), 2):
+        # note: nodelist[i] could be (token.STAR, '*') or (token.NAME, name)
+        names.append(nodelist[i][1])
+      n = Node('from', self.com_dotted_name(nodelist[1]), names)
+      n.lineno = nodelist[0][2]
+      return n
+
+    for i in range(1, len(nodelist), 2):
+      names.append(self.com_dotted_name(nodelist[i]))
+    n = Node('import', names)
+    n.lineno = nodelist[0][2]
+    return n
+
+  def global_stmt(self, nodelist):
+    # global: NAME (',' NAME)*
+    names = [ ]
+    for i in range(1, len(nodelist), 2):
+      names.append(nodelist[i][1])
+    n = Node('global', names)
+    n.lineno = nodelist[0][2]
+    return n
+
+  def exec_stmt(self, nodelist):
+    # exec_stmt: 'exec' expr ['in' expr [',' expr]]
+    expr1 = self.com_node(nodelist[1])
+    if len(nodelist) >= 4:
+      expr2 = self.com_node(nodelist[3])
+      if len(nodelist) >= 6:
+        expr3 = self.com_node(nodelist[5])
+      else:
+        expr3 = None
+    else:
+      expr2 = expr3 = None
+
+    n = Node('exec', expr1, expr2, expr3)
+    n.lineno = nodelist[0][2]
+    return n
+
+  def assert_stmt(self, nodelist):
+    # 'assert': test, [',' test]
+    expr1 = self.com_node(nodelist[1])
+    if (len(nodelist) == 4):
+      expr2 = self.com_node(nodelist[3])
+    else:
+      expr2 = Node('name', 'None')
+    n = Node('assert', expr1, expr2)
+    n.lineno = nodelist[0][2]
+    return n
+
+  def if_stmt(self, nodelist):
+    # if: test ':' suite ('elif' test ':' suite)* ['else' ':' suite]
+    tests = [ ]
+    for i in range(0, len(nodelist) - 3, 4):
+      testNode = self.com_node(nodelist[i + 1])
+      suiteNode = self.com_node(nodelist[i + 3])
+      tests.append((testNode, suiteNode))
+
+    if len(nodelist) % 4 == 3:
+      elseNode = self.com_node(nodelist[-1])
+##      elseNode.lineno = nodelist[-1][1][2]
+    else:
+      elseNode = None
+    n = Node('if', tests, elseNode)
+    n.lineno = nodelist[0][2]
+    return n
+
+  def while_stmt(self, nodelist):
+    # 'while' test ':' suite ['else' ':' suite]
+
+    testNode = self.com_node(nodelist[1])
+    bodyNode = self.com_node(nodelist[3])
+
+    if len(nodelist) > 4:
+      elseNode = self.com_node(nodelist[6])
+    else:
+      elseNode = None
+
+    n = Node('while', testNode, bodyNode, elseNode)
+    n.lineno = nodelist[0][2]
+    return n
+
+  def for_stmt(self, nodelist):
+    # 'for' exprlist 'in' exprlist ':' suite ['else' ':' suite]
+
+    assignNode = self.com_assign(nodelist[1], OP_ASSIGN)
+    listNode = self.com_node(nodelist[3])
+    bodyNode = self.com_node(nodelist[5])
+
+    if len(nodelist) > 8:
+      elseNode = self.com_node(nodelist[8])
+    else:
+      elseNode = None
+
+    n = Node('for', assignNode, listNode, bodyNode, elseNode)
+    n.lineno = nodelist[0][2]
+    return n
+
+  def try_stmt(self, nodelist):
+    # 'try' ':' suite (except_clause ':' suite)+ ['else' ':' suite]
+    # | 'try' ':' suite 'finally' ':' suite
+    if nodelist[3][0] != symbol.except_clause:
+      return self.com_try_finally(nodelist)
+
+    return self.com_try_except(nodelist)
+
+  def suite(self, nodelist):
+    # simple_stmt | NEWLINE INDENT NEWLINE* (stmt NEWLINE*)+ DEDENT
+    if len(nodelist) == 1:
+      return self.com_stmt(nodelist[0])
+
+    stmts = [ ]
+    for node in nodelist:
+      if node[0] == symbol.stmt:
+        self.com_append_stmt(stmts, node)
+    return Node('stmt', stmts)
+
+  # --------------------------------------------------------------
+  #
+  # EXPRESSION NODES  (invoked by com_node())
+  #
+
+  def testlist(self, nodelist):
+    # testlist: expr (',' expr)* [',']
+    # exprlist: expr (',' expr)* [',']
+    return self.com_binary('tuple', nodelist)
+
+  exprlist = testlist
+
+  def test(self, nodelist):
+    # and_test ('or' and_test)* | lambdef
+    if len(nodelist) == 1 and nodelist[0][0] == symbol.lambdef:
+      return self.lambdef(nodelist[0])
+    return self.com_binary('or', nodelist)
+
+  def and_test(self, nodelist):
+    # not_test ('and' not_test)*
+    return self.com_binary('and', nodelist)
+
+  def not_test(self, nodelist):
+    # 'not' not_test | comparison
+    result = self.com_node(nodelist[-1])
+    if len(nodelist) == 2:
+      n = Node('not', result)
+      n.lineno = nodelist[0][2]
+      return n
+    return result
+
+  def comparison(self, nodelist):
+    # comparison: expr (comp_op expr)*
+    node = self.com_node(nodelist[0])
+    if len(nodelist) == 1:
+      return node
+
+    results = [ ]
+    for i in range(2, len(nodelist), 2):
+      nl = nodelist[i-1]
+
+      # comp_op: '<' | '>' | '=' | '>=' | '<=' | '<>' | '!=' | '=='
+      #          | 'in' | 'not' 'in' | 'is' | 'is' 'not'
+      n = nl[1]
+      if n[0] == token.NAME:
+        type = n[1]
+        if len(nl) == 3:
+          if type == 'not':
+            type = 'notin'
+          else:
+            type = 'isnot'
+      else:
+        type = _cmp_types[n[0]]
+
+      lineno = nl[1][2]
+      results.append(type, self.com_node(nodelist[i]))
+
+    # we need a special "compare" node so that we can distinguish
+    #   3 < x < 5   from    (3 < x) < 5
+    # the two have very different semantics and results (note that the
+    # latter form is always true)
+
+    n = Node('compare', node, results)
+    n.lineno = lineno
+    return n
+
+  def expr(self, nodelist):
+    # xor_expr ('|' xor_expr)*
+    return self.com_binary('bitor', nodelist)
+
+  def xor_expr(self, nodelist):
+    # xor_expr ('^' xor_expr)*
+    return self.com_binary('bitxor', nodelist)
+
+  def and_expr(self, nodelist):
+    # xor_expr ('&' xor_expr)*
+    return self.com_binary('bitand', nodelist)
+
+  def shift_expr(self, nodelist):
+    # shift_expr ('<<'|'>>' shift_expr)*
+    node = self.com_node(nodelist[0])
+    for i in range(2, len(nodelist), 2):
+      right = self.com_node(nodelist[i])
+      if nodelist[i-1][0] == token.LEFTSHIFT:
+        node = Node('<<', [node, right])
+        node.lineno = nodelist[1][2]
+      else:
+        node = Node('>>', [node, right])
+        node.lineno = nodelist[1][2]
+    return node
+
+  def arith_expr(self, nodelist):
+    node = self.com_node(nodelist[0])
+    for i in range(2, len(nodelist), 2):
+      right = self.com_node(nodelist[i])
+      if nodelist[i-1][0] == token.PLUS:
+        node = Node('+', [node, right])
+        node.lineno = nodelist[1][2]
+      else:
+        node = Node('-', [node, right])
+        node.lineno = nodelist[1][2]
+    return node
+
+  def term(self, nodelist):
+    node = self.com_node(nodelist[0])
+    for i in range(2, len(nodelist), 2):
+      right = self.com_node(nodelist[i])
+      if nodelist[i-1][0] == token.STAR:
+        node = Node('*', [node, right])
+        node.lineno = nodelist[1][2]
+      elif nodelist[i-1][0] == token.SLASH:
+        node = Node('/', [node, right])
+        node.lineno = nodelist[1][2]
+      else:
+        node = Node('%', [node, right])
+        node.lineno = nodelist[1][2]
+    return node
+
+  def factor(self, nodelist):
+    t = nodelist[0][0]
+    node = self.com_node(nodelist[-1])
+    if t == token.PLUS:
+      node = Node('unary+', node)
+      node.lineno = nodelist[0][2]
+    elif t == token.MINUS:
+      node = Node('unary-', node)
+      node.lineno = nodelist[0][2]
+    elif t == token.TILDE:
+      node = Node('invert', node)
+      node.lineno = nodelist[0][2]
+    return node
+
+  def power(self, nodelist):
+    # power: atom trailer* ('**' factor)*
+    node = self.com_node(nodelist[0])
+    for i in range(1, len(nodelist)):
+      if nodelist[i][0] == token.DOUBLESTAR:
+        n = Node('power', [node, self.com_node(nodelist[i+1])])
+        n.lineno = nodelist[i][2]
+        return n
+
+      node = self.com_apply_trailer(node, nodelist[i])
+
+    return node
+
+  def atom(self, nodelist):
+    t = nodelist[0][0]
+    if t == token.LPAR:
+      if nodelist[1][0] == token.RPAR:
+        n = Node('const', ())
+        n.lineno = nodelist[0][2]
+        return n
+      return self.com_node(nodelist[1])
+
+    if t == token.LSQB:
+      if nodelist[1][0] == token.RSQB:
+        n = Node('const', [ ])
+        n.lineno = nodelist[0][2]
+        return n
+      return self.com_list_constructor(nodelist[1])
+
+    if t == token.LBRACE:
+      if nodelist[1][0] == token.RBRACE:
+        return Node('const', { })
+      return self.com_dictmaker(nodelist[1])
+
+    if t == token.BACKQUOTE:
+      n = Node('backquote', self.com_node(nodelist[1]))
+      n.lineno = nodelist[0][2]
+      return n
+
+    if t == token.NUMBER:
+      ### need to verify this matches compile.c
+      k = eval(nodelist[0][1])
+      n = Node('const', k)
+      n.lineno = nodelist[0][2]
+      return n
+
+    if t == token.STRING:
+      ### need to verify this matches compile.c
+      k = ''
+      for node in nodelist:
+        k = k + eval(node[1])
+      n = Node('const', k)
+      n.lineno = nodelist[0][2]
+      return n
+
+    if t == token.NAME:
+      ### any processing to do?
+      n = Node('name', nodelist[0][1])
+      n.lineno = nodelist[0][2]
+      return n
+
+    raise error, "unknown node type"
+
+  # --------------------------------------------------------------
+  #
+  # INTERNAL PARSING UTILITIES
+  #
+
+  def com_node(self, node):
+    # Note: compile.c has handling in com_node for del_stmt, pass_stmt,
+    #       break_stmt, stmt, small_stmt, flow_stmt, simple_stmt,
+    #       and compound_stmt.
+    #       We'll just dispatch them.
+
+    #
+    # A ';' at the end of a line can make a NEWLINE token appear here,
+    # Render it harmless. (genc discards ('discard', ('const', xxxx)) Nodes)
+    # 
+    if node[0] == token.NEWLINE:
+      return Node('discard', Node('const', None))
+
+    if node[0] not in _legal_node_types:
+      raise error, 'illegal node passed to com_node: %s' % node[0]
+
+    return self._dispatch[node[0]](node[1:])
+
+  def com_arglist(self, nodelist):
+    # varargslist:
+    #   (fpdef ['=' test] ',')* ('*' NAME [',' ('**'|'*' '*') NAME]
+    #  | fpdef ['=' test] (',' fpdef ['=' test])* [',']
+    #  | ('**'|'*' '*') NAME)
+    # fpdef: NAME | '(' fplist ')'
+    # fplist: fpdef (',' fpdef)* [',']
+    names = [ ]
+    defaults = [ ]
+    flags = 0
+
+    i = 0
+    while i < len(nodelist):
+      node = nodelist[i]
+      if node[0] == token.STAR or node[0] == token.DOUBLESTAR:
+        if node[0] == token.STAR:
+          node = nodelist[i+1]
+          if node[0] == token.NAME:
+            names.append(node[1])
+            flags = flags | CO_VARARGS
+            i = i + 3
+
+        if i < len(nodelist):
+          # should be DOUBLESTAR or STAR STAR
+          if nodelist[i][0] == token.DOUBLESTAR:
+            node = nodelist[i+1]
+          else:
+            node = nodelist[i+2]
+          names.append(node[1])
+          flags = flags | CO_VARKEYWORDS
+
+        break
+
+      # fpdef: NAME | '(' fplist ')'
+      names.append(self.com_fpdef(node))
+
+      i = i + 1
+      if i >= len(nodelist):
+        break
+
+      if nodelist[i][0] == token.EQUAL:
+        defaults.append(self.com_node(nodelist[i + 1]))
+        i = i + 2
+      elif len(defaults):
+        # Treat "(a=1, b)" as "(a=1, b=None)"
+        defaults.append(Node('const', None))
+
+      i = i + 1
+
+    return names, defaults, flags
+
+  def com_fpdef(self, node):
+    # fpdef: NAME | '(' fplist ')'
+    if node[1][0] == token.LPAR:
+      return self.com_fplist(node[2])
+    return node[1][1]
+
+  def com_fplist(self, node):
+    # fplist: fpdef (',' fpdef)* [','] 
+    if len(node) == 2:
+      return self.com_fpdef(node[1])
+    list = [ ]
+    for i in range(1, len(node), 2):
+      list.append(self.com_fpdef(node[i]))
+    return tuple(list)
+
+  def com_dotted_name(self, node):
+    # String together the dotted names and return the string
+    name = ""
+    for n in node:
+      if type(n) == type(()) and n[0] == 1:
+        name = name + n[1] + '.'
+    return name[:-1]
+
+  def com_bases(self, node):
+    bases = [ ]
+    for i in range(1, len(node), 2):
+      bases.append(self.com_node(node[i]))
+    return bases
+
+  def com_try_finally(self, nodelist):
+    # try_fin_stmt: "try" ":" suite "finally" ":" suite
+    n = Node('tryfinally', self.com_node(nodelist[2]), self.com_node(nodelist[5]))
+    n.lineno = nodelist[0][2]
+    return n
+
+  def com_try_except(self, nodelist):
+    # try_except: 'try' ':' suite (except_clause ':' suite)* ['else' suite]
+    #tryexcept:  [TryNode, [except_clauses], elseNode)]
+    stmt = self.com_node(nodelist[2])
+    clauses = []
+    elseNode = None
+    for i in range(3, len(nodelist), 3):
+      node = nodelist[i]
+      if node[0] == symbol.except_clause:
+        # except_clause: 'except' [expr [',' expr]] */
+        if len(node) > 2:
+          expr1 = self.com_node(node[2])
+          if len(node) > 4:
+            expr2 = self.com_assign(node[4], OP_ASSIGN)
+          else:
+            expr2 = None
+        else:
+          expr1 = expr2 = None
+        clauses.append(expr1, expr2, self.com_node(nodelist[i+2]))
+
+      if node[0] == token.NAME:
+        elseNode = self.com_node(nodelist[i+2])
+    n = Node('tryexcept', self.com_node(nodelist[2]), clauses, elseNode)
+    n.lineno = nodelist[0][2]
+    return n
+
+  def com_assign(self, node, assigning):
+    # return a node suitable for use as an "lvalue"
+    # loop to avoid trivial recursion
+    while 1:
+      t = node[0]
+      if t == symbol.exprlist or t == symbol.testlist:
+        if len(node) > 2:
+          return self.com_assign_tuple(node, assigning)
+        node = node[1]
+      elif t in _assign_types:
+        if len(node) > 2:
+          raise SyntaxError, "can't assign to operator"
+        node = node[1]
+      elif t == symbol.power:
+        if node[1][0] != symbol.atom:
+          raise SyntaxError, "can't assign to operator"
+        if len(node) > 2:
+          primary = self.com_node(node[1])
+          for i in range(2, len(node)-1):
+            ch = node[i]
+            if ch[0] == token.DOUBLESTAR:
+              raise SyntaxError, "can't assign to operator"
+            primary = self.com_apply_trailer(primary, ch)
+          return self.com_assign_trailer(primary, node[-1], assigning)
+        node = node[1]
+      elif t == symbol.atom:
+        t = node[1][0]
+        if t == token.LPAR:
+          node = node[2]
+          if node[0] == token.RPAR:
+            raise SyntaxError, "can't assign to ()"
+        elif t == token.LSQB:
+          node = node[2]
+          if node[0] == token.RSQB:
+            raise SyntaxError, "can't assign to []"
+          return self.com_assign_list(node, assigning)
+        elif t == token.NAME:
+          return self.com_assign_name(node[1], assigning)
+        else:
+          raise SyntaxError, "can't assign to literal"
+      else:
+        raise SyntaxError, "bad assignment"
+
+  def com_assign_tuple(self, node, assigning):
+    assigns = [ ]
+    for i in range(1, len(node), 2):
+      assigns.append(self.com_assign(node[i], assigning))
+    return Node('ass_tuple', assigns)
+
+  def com_assign_list(self, node, assigning):
+    assigns = [ ]
+    for i in range(1, len(node), 2):
+      assigns.append(self.com_assign(node[i], assigning))
+    return Node('ass_list', assigns)
+
+  def com_assign_name(self, node, assigning):
+    return Node('ass_name', node[1], assigning)
+
+  def com_assign_trailer(self, primary, node, assigning):
+    t = node[1][0]
+    if t == token.LPAR:
+      raise SyntaxError, "can't assign to function call"
+    if t == token.DOT:
+      return self.com_assign_attr(primary, node[2], assigning)
+    if t == token.LSQB:
+      return self.com_subscriptlist(primary, node[2], assigning)
+    raise SyntaxError, "unknown trailer type: %s" % t
+
+  def com_assign_attr(self, primary, node, assigning):
+    return Node('ass_attr', primary, node[1], assigning)
+
+  def com_binary(self, type, nodelist):
+    "Compile 'NODE (OP NODE)*' into (type, [ node1, ..., nodeN ])."
+    if len(nodelist) == 1:
+      return self.com_node(nodelist[0])
+    items = [ ]
+    for i in range(0, len(nodelist), 2):
+      items.append(self.com_node(nodelist[i]))
+    return Node(type, items)
+
+  def com_stmt(self, node):
+    #pprint.pprint(node)
+    result = self.com_node(node)
+    try:
+      result[0]
+    except:
+      print node[0]
+    if result[0] == 'stmt':
+      return result
+    return Node('stmt', [ result ])
+
+  def com_append_stmt(self, stmts, node):
+    result = self.com_node(node)
+    try:
+      result[0]
+    except:
+      print node
+    if result[0] == 'stmt':
+      stmts[len(stmts):] = result[1]
+    else:
+      stmts.append(result)
+
+  def com_list_constructor(self, nodelist):
+    values = [ ]
+    for i in range(1, len(nodelist), 2):
+      values.append(self.com_node(nodelist[i]))
+    return Node('list', values)
+
+  def com_dictmaker(self, nodelist):
+    # dictmaker: test ':' test (',' test ':' value)* [',']
+    items = [ ]
+    for i in range(1, len(nodelist), 4):
+      items.append(self.com_node(nodelist[i]), self.com_node(nodelist[i+2]))
+    return Node('dict', items)
+
+  def com_apply_trailer(self, primaryNode, nodelist):
+    t = nodelist[1][0]
+    if t == token.LPAR:
+      return self.com_call_function(primaryNode, nodelist[2])
+    if t == token.DOT:
+      return self.com_select_member(primaryNode, nodelist[2])
+    if t == token.LSQB:
+      return self.com_subscriptlist(primaryNode, nodelist[2], OP_APPLY)
+
+    raise SyntaxError, 'unknown node type: %s' % t
+
+  def com_select_member(self, primaryNode, nodelist):
+    if nodelist[0] != token.NAME:
+      raise SyntaxError, "member must be a name"
+    n = Node('getattr', primaryNode, nodelist[1])
+    n.lineno = nodelist[2]
+    return n
+
+  def com_call_function(self, primaryNode, nodelist):
+    if nodelist[0] == token.RPAR:
+      return Node('call_func', primaryNode, [ ])
+    args = [ ]
+    kw = 0
+    for i in range(1, len(nodelist), 2):
+      kw, result = self.com_argument(nodelist[i], kw)
+      args.append(result)
+    return Node('call_func', primaryNode, args)
+
+  def com_argument(self, nodelist, kw):
+    if len(nodelist) == 2:
+      if kw:
+        raise SyntaxError, "non-keyword arg after keyword arg"
+      return 0, self.com_node(nodelist[1])
+    result = self.com_node(nodelist[3])
+    n = nodelist[1]
+    while len(n) == 2 and n[0] != token.NAME:
+      n = n[1]
+    if n[0] != token.NAME:
+      raise SyntaxError, "keyword can't be an expression (%s)"%n[0]
+    n = Node('keyword', n[1], result)
+    n.lineno = result.lineno
+    return 1, n
+
+  def com_subscriptlist(self, primary, nodelist, assigning):
+    # slicing:      simple_slicing | extended_slicing
+    # simple_slicing:   primary "[" short_slice "]"
+    # extended_slicing: primary "[" slice_list "]" 
+    # slice_list:   slice_item ("," slice_item)* [","]
+
+    # backwards compat slice for '[i:j]'
+    if len(nodelist) == 2:
+      sub = nodelist[1]
+      if (sub[1][0] == token.COLON or \
+              (len(sub) > 2 and sub[2][0] == token.COLON)) and \
+             sub[-1][0] != symbol.sliceop:
+        return self.com_slice(primary, sub, assigning)
+
+    subscripts = [ ]
+    for i in range(1, len(nodelist), 2):
+      subscripts.append(self.com_subscript(nodelist[i]))
+
+    return Node('subscript', primary, assigning, subscripts)
+
+  def com_subscript(self, node):
+    # slice_item: expression | proper_slice | ellipsis
+    ch = node[1]
+    if ch[0] == token.DOT and node[2][0] == token.DOT:
+      return ('ellipsis', None)
+    if ch[0] == token.COLON or len(node) > 2:
+      return self.com_sliceobj(node)
+    return self.com_node(ch)
+
+  def com_sliceobj(self, node):
+    # proper_slice: short_slice | long_slice
+    # short_slice:  [lower_bound] ":" [upper_bound]
+    # long_slice:   short_slice ":" [stride]
+    # lower_bound:  expression
+    # upper_bound:  expression
+    # stride:       expression
+    #
+    # Note: a stride may be further slicing...
+
+    items = [ ]
+
+    if node[1][0] == token.COLON:
+      items.append(Node('const', None))
+      i = 2
+    else:
+      items.append(self.com_node(node[1]))
+      # i == 2 is a COLON
+      i = 3
+
+    if i < len(node) and node[i][0] == symbol.test:
+      items.append(self.com_node(node[i]))
+      i = i + 1
+    else:
+      items.append(Node('const', None))
+
+    # a short_slice has been built. look for long_slice now by looking
+    # for strides...
+    for j in range(i, len(node)):
+      ch = node[j]
+      if len(ch) == 2:
+        items.append(Node('const', None))
+      else:
+        items.append(self.com_node(ch[2]))
+
+    return Node('sliceobj', items)
+
+  def com_slice(self, primary, node, assigning):
+    # short_slice:  [lower_bound] ":" [upper_bound]
+    lower = upper = None
+    if len(node) == 3:
+      if node[1][0] == token.COLON:
+        upper = self.com_node(node[2])
+      else:
+        lower = self.com_node(node[1])
+    elif len(node) == 4:
+      lower = self.com_node(node[1])
+      upper = self.com_node(node[3])
+    return Node('slice', primary, assigning, lower, upper)
+
+  def get_docstring(self, node, n=None):
+    if n is None:
+      n = node[0]
+      node = node[1:]
+    if n == symbol.suite:
+      if len(node) == 1:
+        return self.get_docstring(node[0])
+      for sub in node:
+        if sub[0] == symbol.stmt:
+          return self.get_docstring(sub)
+      return None
+    if n == symbol.file_input:
+      for sub in node:
+        if sub[0] == symbol.stmt:
+          return self.get_docstring(sub)
+      return None
+    if n == symbol.atom:
+      if node[0][0] == token.STRING:
+        s = ''
+        for t in node:
+          s = s + eval(t[1])
+        return s
+      return None
+    if n == symbol.stmt or n == symbol.simple_stmt or n == symbol.small_stmt:
+      return self.get_docstring(node[0])
+    if n in _doc_nodes and len(node) == 1:
+      return self.get_docstring(node[0])
+    return None
+
+
+_doc_nodes = [
+  symbol.expr_stmt,
+  symbol.testlist,
+  symbol.test,
+  symbol.and_test,
+  symbol.not_test,
+  symbol.comparison,
+  symbol.expr,
+  symbol.xor_expr,
+  symbol.and_expr,
+  symbol.shift_expr,
+  symbol.arith_expr,
+  symbol.term,
+  symbol.factor,
+  symbol.power,
+  ]
+
+# comp_op: '<' | '>' | '=' | '>=' | '<=' | '<>' | '!=' | '=='
+#             | 'in' | 'not' 'in' | 'is' | 'is' 'not'
+_cmp_types = {
+  token.LESS : '<',
+  token.GREATER : '>',
+  token.EQEQUAL : '==',
+  token.EQUAL : '==',
+  token.LESSEQUAL : '<=',
+  token.GREATEREQUAL : '>=',
+  token.NOTEQUAL : '!=',
+  }
+
+_legal_node_types = [
+  symbol.funcdef,
+  symbol.classdef,
+  symbol.stmt,
+  symbol.small_stmt,
+  symbol.flow_stmt,
+  symbol.simple_stmt,
+  symbol.compound_stmt,
+  symbol.expr_stmt,
+  symbol.print_stmt,
+  symbol.del_stmt,
+  symbol.pass_stmt,
+  symbol.break_stmt,
+  symbol.continue_stmt,
+  symbol.return_stmt,
+  symbol.raise_stmt,
+  symbol.import_stmt,
+  symbol.global_stmt,
+  symbol.exec_stmt,
+  symbol.assert_stmt,
+  symbol.if_stmt,
+  symbol.while_stmt,
+  symbol.for_stmt,
+  symbol.try_stmt,
+  symbol.suite,
+  symbol.testlist,
+  symbol.test,
+  symbol.and_test,
+  symbol.not_test,
+  symbol.comparison,
+  symbol.exprlist,
+  symbol.expr,
+  symbol.xor_expr,
+  symbol.and_expr,
+  symbol.shift_expr,
+  symbol.arith_expr,
+  symbol.term,
+  symbol.factor,
+  symbol.power,
+  symbol.atom,
+  ]
+
+_assign_types = [
+  symbol.test,
+  symbol.and_test,
+  symbol.not_test,
+  symbol.comparison,
+  symbol.expr,
+  symbol.xor_expr,
+  symbol.and_expr,
+  symbol.shift_expr,
+  symbol.arith_expr,
+  symbol.term,
+  symbol.factor,
+  ]
+
+# Local Variables: 
+# mode: python     
+# indent-tabs-mode: nil 
+# py-indent-offset: 2 
+# py-smart-indentation: nil 
+# End: 
+