ticket 436: efficiently support char*.decode() through C-API calls

Cython/Compiler/Main.py

@@ -136,7 +136,7 @@ class Context(object):
             IntroduceBufferAuxiliaryVars(self),
             _check_c_declarations,
             AnalyseExpressionsTransform(self),
-            OptimizeBuiltinCalls(),
+            OptimizeBuiltinCalls(self),
             IterationTransform(),
             SwitchTransform(),
             DropRefcountingTransform(),

Cython/Compiler/ParseTreeTransforms.py

-from Cython.Compiler.Visitor import VisitorTransform, CythonTransform, TreeVisitor
+from Cython.Compiler.Visitor import VisitorTransform, TreeVisitor
+from Cython.Compiler.Visitor import CythonTransform, EnvTransform
 from Cython.Compiler.ModuleNode import ModuleNode
 from Cython.Compiler.Nodes import *
 from Cython.Compiler.ExprNodes import *
@@ -938,21 +939,6 @@ class GilCheck(VisitorTransform):
         return node
 
 
-class EnvTransform(CythonTransform):
-    """
-    This transformation keeps a stack of the environments. 
-    """
-    def __call__(self, root):
-        self.env_stack = [root.scope]
-        return super(EnvTransform, self).__call__(root)        
-    
-    def visit_FuncDefNode(self, node):
-        self.env_stack.append(node.local_scope)
-        self.visitchildren(node)
-        self.env_stack.pop()
-        return node
-
-
 class TransformBuiltinMethods(EnvTransform):
 
     def visit_SingleAssignmentNode(self, node):

Cython/Compiler/Visitor.py

@@ -306,6 +306,22 @@ class ScopeTrackingTransform(CythonTransform):
     def visit_CStructOrUnionDefNode(self, node):
         return self.visit_scope(node, 'struct')
 
+
+class EnvTransform(CythonTransform):
+    """
+    This transformation keeps a stack of the environments. 
+    """
+    def __call__(self, root):
+        self.env_stack = [root.scope]
+        return super(EnvTransform, self).__call__(root)        
+    
+    def visit_FuncDefNode(self, node):
+        self.env_stack.append(node.local_scope)
+        self.visitchildren(node)
+        self.env_stack.pop()
+        return node
+
+
 class RecursiveNodeReplacer(VisitorTransform):
     """
     Recursively replace all occurrences of a node in a subtree by

tests/run/carray_slicing.pyx

+
+cdef char* cstring = "abcABCqtp"
+
+def slice_charptr_end():
+    """
+    >>> print str(slice_charptr_end()).replace("b'", "'")
+    ('a', 'abc', 'abcABCqtp')
+    """
+    return cstring[:1], cstring[:3], cstring[:9]
+
+def slice_charptr_decode():
+    """
+    >>> print str(slice_charptr_decode()).replace("u'", "'")
+    ('a', 'abc', 'abcABCqtp')
+    """
+    return (cstring[:1].decode('UTF-8'),
+            cstring[:3].decode('UTF-8'),
+            cstring[:9].decode('UTF-8'))
+
+def slice_charptr_decode_errormode():
+    """
+    >>> print str(slice_charptr_decode_errormode()).replace("u'", "'")
+    ('a', 'abc', 'abcABCqtp')
+    """
+    return (cstring[:1].decode('UTF-8', 'strict'),
+            cstring[:3].decode('UTF-8', 'replace'),
+            cstring[:9].decode('UTF-8', 'unicode_escape'))