[Python-checkins] r64296 - in python/branches/tlee-ast-optimize: Lib/test/test_optimizer.py Python/optimize.c

[thomas.lee]

Author: thomas.lee
Date: Sun Jun 15 17:08:51 2008
New Revision: 64296

Log:
Remove optimizations for True/False named pseudo-constants, since it breaks a bunch of 2.x semantics that may be relied upon. Added a test for enforcing the 2.6 semantics for now. Finally, added an error check for OOM to optimize_name.

Modified:
   python/branches/tlee-ast-optimize/Lib/test/test_optimizer.py
   python/branches/tlee-ast-optimize/Python/optimize.c

Modified: python/branches/tlee-ast-optimize/Lib/test/test_optimizer.py
==============================================================================
--- python/branches/tlee-ast-optimize/Lib/test/test_optimizer.py	(original)
+++ python/branches/tlee-ast-optimize/Lib/test/test_optimizer.py	Sun Jun 15 17:08:51 2008
@@ -139,7 +139,8 @@
         self.assertNum(-5, "-5")
         self.assertNum(True, "not 0")
         self.assertNum(-3, "-+3")
-        self.assertNum(False, "not True")
+        # XXX: cannot be enforced in 2.6
+        #self.assertNum(False, "not True")
         self.assertNum(True, "not None")
 
     def test_unary_failure_left_until_runtime(self):
@@ -249,7 +250,7 @@
         self.assertEqual((1, 2, 3), ast.body[0].iter.value)
 
     def test_named_constants(self):
-        tests = [None, True, False]
+        tests = [None]
 
         for obj in tests:
             code = repr(obj)
@@ -273,6 +274,19 @@
         self.assertEqual(_ast.Return, ast.body[0].body[0].body[1].__class__)
         self.assertEqual('y', ast.body[0].body[0].body[1].value.id)
 
+    def test_assignment_to_true_works(self):
+        # ---------------------------------------------------------------------
+        #   Please note that this test is for <2.6 to ensure that
+        #   assignment to True and False are possible despite any
+        #   optimizations.
+        # ---------------------------------------------------------------------
+
+        True = 0
+        assert not True
+
+        False = 1
+        assert False
+
 def test_main():
     test_support.run_unittest(AstOptimizerTest)
 

Modified: python/branches/tlee-ast-optimize/Python/optimize.c
==============================================================================
--- python/branches/tlee-ast-optimize/Python/optimize.c	(original)
+++ python/branches/tlee-ast-optimize/Python/optimize.c	Sun Jun 15 17:08:51 2008
@@ -34,15 +34,6 @@
     else if (expr->kind == Num_kind) {
         return expr->v.Num.n;
     }
-    else if (expr->kind == Name_kind) {
-        const char* name = PyString_AS_STRING(expr->v.Name.id);
-        if (strcmp(name, "True") == 0)
-            return Py_True;
-        else if (strcmp(name, "False") == 0)
-            return Py_False;
-        else if (strcmp(name, "None") == 0)
-            return Py_None;
-    }
     else if (expr->kind == Const_kind) {
         return expr->v.Const.value;
     }
@@ -916,10 +907,16 @@
     const char* id = PyString_AS_STRING(expr->v.Name.id);
     PyObject* constvalue = NULL;
 
+    /* allow "assignment to none" error to naturally occur */
+    if (expr->v.Name.ctx != Load)
+        return 1;
+
     if (strcmp(id, "None") == 0) {
         Py_INCREF(Py_None);
         constvalue = Py_None;
     }
+/* this is not doable in 2.x ... */
+#if 0
     else if (strcmp(id, "True") == 0) {
         Py_INCREF(Py_True);
         constvalue = Py_True;
@@ -928,10 +925,14 @@
         Py_INCREF(Py_False);
         constvalue = Py_False;
     }
+#endif
 
-    if (constvalue != NULL)
+    if (constvalue != NULL) {
         *expr_ptr = Const(constvalue, expr->lineno,
                             expr->col_offset, arena);
+        if (*expr_ptr == NULL)
+            return 0;
+    }
 
     return 1;
 }
@@ -1007,12 +1008,7 @@
             }
         case Name_kind:
             {
-                /* we probably only want to optimize loads ... storing values
-                 * in a Const makes no sense!
-                 */
-                if (expr->v.Name.ctx == Load)
-                    return optimize_name(expr_ptr, ste, arena);
-                /* fall through */
+                return optimize_name(expr_ptr, ste, arena);
             }
         case Num_kind:
         case Str_kind: