# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1276388675 -7200
# Node ID c7c2119483cf3ce47eb80ecc8ddd0eea5370c663
# Parent  334af78f7931b7fcd05d714d00f44999d7e43325
Fixed exception attribute initialisation for translation errors.
Reintroduced the _scope attribute on AST nodes in order to support supposedly
harmless changes in scope (such as the "importing" of a built-in or global into
a local scope where the name is redefined subsequently).
Reorganised the tests according to the above shadowing policy change.
Introduced tentative slicing support plus built-in functions that rely on
slicing.

diff -r 334af78f7931 -r c7c2119483cf TO_DO.txt
--- a/TO_DO.txt	Sat Jun 12 23:09:30 2010 +0200
+++ b/TO_DO.txt	Sun Jun 13 02:24:35 2010 +0200
@@ -1,12 +1,27 @@
+Check name origin where multiple branches could yield multiple scope interpretations:
+
+----
+try:
+    set # built-in name
+except NameError:
+    from sets import Set as set # local definition of name
+
+set # could be confused by the local definition at run-time
+----
+
 Support __init__ traversal (and other implicit names) more effectively.
 
 Check context_value initialisation (avoiding or handling None effectively).
 
+__getitem__ could be written in Python, using a native method only to access fragments.
+Support slicing.
+Consider better "macro" support where new expressions need to be generated and processed.
+
+**** Constant attribute users need not maintain usage since they are already resolved. ****
+
 Loop entry points should capture usage to update later assignments in the loop.
 The continue and break statements should affect usage propagation.
 
-Constant attribute users need not maintain usage since they are already resolved.
-
 Consider handling CallFunc in micropython.inspect in order to produce instances of specific classes.
 Then, consider adding support for guard removal/verification where known instances are involved.
 Consider handling branches of values within namespaces in order to support more precise value usage.
diff -r 334af78f7931 -r c7c2119483cf lib/builtins.py
--- a/lib/builtins.py	Sat Jun 12 23:09:30 2010 +0200
+++ b/lib/builtins.py	Sun Jun 13 02:24:35 2010 +0200
@@ -233,8 +233,7 @@
 class set(object):
     def __init__(self, iterable): pass
 
-class slice(object):
-    def __init__(self, start_or_end, end=None, step=None): pass
+# See below for slice.
 
 class str(basestring):
     pass
@@ -277,6 +276,7 @@
 
         self.step = step
         self.current = self.start
+        self.limited = self.end is not None
 
     def __iter__(self):
 
@@ -288,13 +288,24 @@
 
         "Return the next item or raise a StopIteration exception."
 
-        if self.step < 0 and self.current <= self.end or self.step > 0 and self.current >= self.end:
-            raise StopIteration()
+        if self.limited:
+            if self.step < 0 and self.current <= self.end or self.step > 0 and self.current >= self.end:
+                raise StopIteration()
 
         current = self.current
         self.current += self.step
         return current
 
+class slice(xrange):
+
+    "Implementation of slice."
+
+    def __init__(self, start_or_end=None, end=None, step=1):
+
+        "Initialise the slice with the given 'start_or_end', 'end' and 'step'."
+
+        xrange.__init__(self, start_or_end, end, step)
+
 # Exceptions and warnings.
 
 class BaseException(object):
@@ -402,9 +413,29 @@
     return obj.__len__()
 
 def locals(): pass
+
 def map(function, *args): pass
-def max(*args): pass
-def min(*args): pass
+
+def max(*args):
+
+    "Implementation of max."
+
+    highest = args[0]
+    for arg in args[1:]:
+        if arg > highest:
+            highest = arg
+    return highest
+
+def min(*args):
+
+    "Implementation of min."
+
+    lowest = args[0]
+    for arg in args[1:]:
+        if arg > lowest:
+            lowest = arg
+    return lowest
+
 def oct(number): pass
 def open(name, mode=None, buffering=None): pass
 def ord(c): pass
diff -r 334af78f7931 -r c7c2119483cf micropython/ast.py
--- a/micropython/ast.py	Sat Jun 12 23:09:30 2010 +0200
+++ b/micropython/ast.py	Sun Jun 13 02:24:35 2010 +0200
@@ -429,7 +429,25 @@
         else:
             self._visitName(node, self.name_load_instructions)
 
-    def visitSlice(self, node): raise TranslationNotImplementedError("Slice")
+    def visitSlice(self, node):
+        if node.lower is None:
+            if node.upper is None:
+                args = []
+            else:
+                args = [compiler.ast.Name("None"), node.upper]
+        else:
+            args = [node.lower]
+
+        # NOTE: Need to guarantee reliable access to the slice built-in.
+
+        slice = compiler.ast.CallFunc(compiler.ast.Name("slice"), args)
+
+        self.dispatch(node.expr)
+        self._startCallFunc()
+        self._generateAttr(node, "__getitem__", self.attribute_load_instructions)
+        temp_target, target, temp_context = self._generateCallFunc([slice], node)
+        self._doCallFunc(temp_target, target)
+        self._endCallFunc(temp_target, target, temp_context)
 
     def visitSubscript(self, node):
         self.dispatch(node.expr)
diff -r 334af78f7931 -r c7c2119483cf micropython/common.py
--- a/micropython/common.py	Sat Jun 12 23:09:30 2010 +0200
+++ b/micropython/common.py	Sun Jun 13 02:24:35 2010 +0200
@@ -38,7 +38,13 @@
         except NodeProcessingError, exc:
             if exc.astnode is None:
                 exc.astnode = node
-                exc.unit_name = self.full_name()
+
+                # NOTE: Should perhaps specialise the subclasses appropriately.
+
+                if hasattr(self, "unit"):
+                    exc.unit_name = self.unit.full_name()
+                else:
+                    exc.unit_name = self.full_name()
             raise
 
 # Errors.
diff -r 334af78f7931 -r c7c2119483cf micropython/inspect.py
--- a/micropython/inspect.py	Sat Jun 12 23:09:30 2010 +0200
+++ b/micropython/inspect.py	Sun Jun 13 02:24:35 2010 +0200
@@ -273,7 +273,7 @@
         # Store in the module.
 
         if not self.namespaces:
-            if self.used_in_scope(name, "builtins"):
+            if self.in_loop and self.used_in_scope(name, "builtins"):
                 raise InspectError("Name %r already used as a built-in." % name)
             else:
                 self.set(name, obj, not self.in_loop)
@@ -283,9 +283,9 @@
         else:
             locals = self.namespaces[-1]
 
-            if locals.used_in_scope(name, "global") and not name in locals.globals:
+            if self.in_loop and locals.used_in_scope(name, "global") and not name in locals.globals:
                 raise InspectError("Name %r already used as global." % name)
-            elif locals.used_in_scope(name, "builtins"):
+            elif self.in_loop and locals.used_in_scope(name, "builtins"):
                 raise InspectError("Name %r already used as a built-in." % name)
             else:
                 locals.set(name, obj, not self.in_loop)
@@ -939,6 +939,7 @@
 
         if self.importer.predefined_constants.has_key(name):
             attr = self.importer.get_predefined_constant(name)
+            node._scope = "constant"
 
         # Locals.
 
@@ -948,6 +949,7 @@
             # Note usage of the local (potentially a class attribute).
 
             self.use_specific_attribute(None, name)
+            node._scope = "local"
 
         # Globals.
 
@@ -957,27 +959,26 @@
             # Note usage of the module attribute.
 
             self.use_specific_attribute(self.full_name(), name)
+            node._scope = "global"
 
             # Note global usage in any local namespace.
 
             if self.namespaces:
-                if not self.namespaces[-1].note_scope(name, "global"):
-                    raise InspectError("Name %r cannot be used as global." % name)
+                self.namespaces[-1].note_scope(name, "global")
 
         # Builtins.
 
         elif self.builtins is not None and self.builtins.has_key(name):
             attr = self.builtins[name]
             self.use_specific_attribute(self.builtins.full_name(), name)
+            node._scope = "builtins"
 
             # Note builtins usage in any local namespace.
 
             if self.namespaces:
-                if not self.namespaces[-1].note_scope(name, "builtins"):
-                    raise InspectError("Name %r cannot be used as a built-in." % name)
+                self.namespaces[-1].note_scope(name, "builtins")
             else:
-                if not self.note_scope(name, "builtins"):
-                    raise InspectError("Name %r cannot be used as a built-in." % name)
+                self.note_scope(name, "builtins")
 
         # Unknown.
 
@@ -1005,7 +1006,10 @@
 
     visitRightShift = _visitBinary
 
-    visitSlice = OP
+    def visitSlice(self, node):
+        self.use_name("slice", node)
+        self.use_name("__getitem__", node)
+        self.OP(node)
 
     visitSliceobj = OP
 
diff -r 334af78f7931 -r c7c2119483cf micropython/trans.py
--- a/micropython/trans.py	Sat Jun 12 23:09:30 2010 +0200
+++ b/micropython/trans.py	Sun Jun 13 02:24:35 2010 +0200
@@ -1160,7 +1160,7 @@
 
         # Get the expected scope of the name.
 
-        scope = self.get_scope(name)
+        scope = getattr(node, "_scope", None) or self.get_scope(name)
 
         #print self.module.name, node.lineno, name, predicted_scope
         self._generateName(name, scope, classes, node)
diff -r 334af78f7931 -r c7c2119483cf tests/failure/shadow_class_global.py
--- a/tests/failure/shadow_class_global.py	Sat Jun 12 23:09:30 2010 +0200
+++ b/tests/failure/shadow_class_global.py	Sun Jun 13 02:24:35 2010 +0200
@@ -4,7 +4,8 @@
     return x
 
 class C:
-    e = e
+    for x in range(0, 10):
+        e = e # right hand side name changes origin
 
 c = C()
 
diff -r 334af78f7931 -r c7c2119483cf tests/failure/shadow_class_global_reassign.py
--- a/tests/failure/shadow_class_global_reassign.py	Sat Jun 12 23:09:30 2010 +0200
+++ b/tests/failure/shadow_class_global_reassign.py	Sun Jun 13 02:24:35 2010 +0200
@@ -4,12 +4,17 @@
     return x
 
 class C:
-    e = f
+    i = 2
+
+    while i > 0:
+        e = f # right hand side name changes origin
 
-    def f(self, x):
-        return x
+        def f(self, x):
+            return 3
+
+        i -= 1
 
 c = C()
-c.f(1)
+result_3 = c.f(1)
 
 # vim: tabstop=4 expandtab shiftwidth=4
diff -r 334af78f7931 -r c7c2119483cf tests/failure/shadow_globals_builtins.py
--- a/tests/failure/shadow_globals_builtins.py	Sat Jun 12 23:09:30 2010 +0200
+++ b/tests/failure/shadow_globals_builtins.py	Sun Jun 13 02:24:35 2010 +0200
@@ -1,10 +1,14 @@
 #!/usr/bin/env python
 
-c = max(4, 5)
+i = 2
+while i > 0:
+    c = len([3, 4, 5]) # right hand side name changes origin
 
-def max(a, b):
-    return a
+    def len(a):
+        return a
 
-result_2 = max(2, 3)
+    i -= 1
+
+result_2 = len(2)
 
 # vim: tabstop=4 expandtab shiftwidth=4
diff -r 334af78f7931 -r c7c2119483cf tests/failure/shadow_locals_globals.py
--- a/tests/failure/shadow_locals_globals.py	Sat Jun 12 23:09:30 2010 +0200
+++ b/tests/failure/shadow_locals_globals.py	Sun Jun 13 02:24:35 2010 +0200
@@ -3,8 +3,11 @@
 a = 1
 
 def before():
-    b = a
-    a = 2
+    i = 2
+    while i > 0:
+        b = a # right hand side name changes origin
+        a = 2
+        i -= 1
     return b
 
 result1_1 = before()
diff -r 334af78f7931 -r c7c2119483cf tests/failure/shadow_locals_globals_reassign.py
--- a/tests/failure/shadow_locals_globals_reassign.py	Sat Jun 12 23:09:30 2010 +0200
+++ b/tests/failure/shadow_locals_globals_reassign.py	Sun Jun 13 02:24:35 2010 +0200
@@ -2,16 +2,13 @@
 
 a = 1
 
-def before():
-    b = a
-    a = 2
-    return b
-
 def reassign():
-    a = a
+    i = 2
+    while i > 0:
+        a = a # right hand side name changes origin
+        i -= 1
     return a
 
-result1_1 = before()
 result2_1 = reassign()
 
 # vim: tabstop=4 expandtab shiftwidth=4
diff -r 334af78f7931 -r c7c2119483cf tests/shadow_class_global_reassign.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/shadow_class_global_reassign.py	Sun Jun 13 02:24:35 2010 +0200
@@ -0,0 +1,15 @@
+#!/usr/bin/env python
+
+def f(self, x):
+    return x
+
+class C:
+    e = f
+
+    def f(self, x):
+        return 3
+
+c = C()
+result_3 = c.f(1)
+
+# vim: tabstop=4 expandtab shiftwidth=4
diff -r 334af78f7931 -r c7c2119483cf tests/shadow_globals_builtins.py
--- a/tests/shadow_globals_builtins.py	Sat Jun 12 23:09:30 2010 +0200
+++ b/tests/shadow_globals_builtins.py	Sun Jun 13 02:24:35 2010 +0200
@@ -1,8 +1,10 @@
 #!/usr/bin/env python
 
-def max(a, b):
+c = len([3, 4, 5])
+
+def len(a):
     return a
 
-result_2 = max(2, 3)
+result_2 = len(2)
 
 # vim: tabstop=4 expandtab shiftwidth=4
diff -r 334af78f7931 -r c7c2119483cf tests/shadow_locals_globals_reassign.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/shadow_locals_globals_reassign.py	Sun Jun 13 02:24:35 2010 +0200
@@ -0,0 +1,17 @@
+#!/usr/bin/env python
+
+a = 1
+
+def before():
+    b = a
+    a = 2
+    return b
+
+def reassign():
+    a = a
+    return a
+
+result1_1 = before()
+result2_1 = reassign()
+
+# vim: tabstop=4 expandtab shiftwidth=4
diff -r 334af78f7931 -r c7c2119483cf tests/shadow_locals_globals_unbound_local.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/shadow_locals_globals_unbound_local.py	Sun Jun 13 02:24:35 2010 +0200
@@ -0,0 +1,12 @@
+#!/usr/bin/env python
+
+a = 1
+
+def before():
+    b = a
+    a = 2
+    return b
+
+result1_1 = before()
+
+# vim: tabstop=4 expandtab shiftwidth=4