Add Python 2.3 rule for "if 1: ..."

Fully fixes #97 for Python 2.3. Python 2.4 was fixed in a previous commit.

uncompyle6/parsers/parse23.py

@@ -1,4 +1,4 @@
-#  Copyright (c) 2016 Rocky Bernstein
+#  Copyright (c) 2016-2017 Rocky Bernstein
 #  Copyright (c) 2000-2002 by hartmut Goebel <hartmut@goebel.noris.de>
 #  Copyright (c) 1999 John Aycock
 
@@ -14,6 +14,17 @@ class Python23Parser(Python24Parser):
 
     def p_misc23(self, args):
         '''
+        # Python 2.4 only adds something like the below for if 1:
+        # However we will just treat it as a noop (which of course messes up
+        # simple verify of bytecode.
+        # See also below in reduce_is_invalid where we check that the JUMP_FORWARD
+        # target matches the COME_FROM target
+        stmt     ::= if1_stmt
+        if1_stmt ::= JUMP_FORWARD JUMP_IF_FALSE THEN POP_TOP COME_FROM
+                     stmts
+                     JUMP_FORWARD COME_FROM POP_TOP COME_FROM
+
+
         # Used to keep semantic positions the same across later versions
         # of Python
         _while1test ::= SETUP_LOOP JUMP_FORWARD JUMP_IF_FALSE POP_TOP COME_FROM
@@ -33,6 +44,23 @@ class Python23Parser(Python24Parser):
         lc_body ::= LOAD_FAST expr LIST_APPEND
         '''
 
+    def add_custom_rules(self, tokens, customize):
+        super(Python23Parser, self).add_custom_rules(tokens, customize)
+
+    def reduce_is_invalid(self, rule, ast, tokens, first, last):
+        invalid = super(Python24Parser,
+                        self).reduce_is_invalid(rule, ast,
+                                                tokens, first, last)
+        if invalid:
+            return invalid
+
+        # FiXME: this code never gets called...
+        lhs = rule[0]
+        if lhs == 'nop_stmt':
+            return not int(tokens[first].pattr) == tokens[last].offset
+
+        return False
+
 class Python23ParserSingle(Python23Parser, PythonParserSingle):
     pass
 

uncompyle6/semantics/pysource.py

@@ -218,6 +218,11 @@ class SourceWalker(GenericASTTraversal, object):
                 'importlist2':	( '%C', (0, maxint, ', ') ),
                 })
             if version <= 2.4:
+                if version == 2.3:
+                    TABLE_DIRECT.update({
+                        'if1_stmt':	( '%|if 1\n%+%c%-', 5 )
+                    })
+
                 global NAME_MODULE
                 NAME_MODULE = AST('stmt',
                                   [ AST('assign',