get the symtable module back in working order

- Fix broken functions
- Add (hopefully) extensive tests
- Modernize a little

Lib/symtable.py

 """Interface to the compiler's internal symbol tables"""
 
 import _symtable
-from _symtable import USE, DEF_GLOBAL, DEF_LOCAL, DEF_PARAM, \
-     DEF_STAR, DEF_DOUBLESTAR, DEF_INTUPLE, DEF_FREE, \
-     DEF_FREE_GLOBAL, DEF_FREE_CLASS, DEF_IMPORT, DEF_BOUND, \
-     OPT_IMPORT_STAR, OPT_EXEC, OPT_BARE_EXEC
+from _symtable import (USE, DEF_GLOBAL, DEF_LOCAL, DEF_PARAM,
+     DEF_STAR, DEF_DOUBLESTAR, DEF_INTUPLE, DEF_FREE,
+     DEF_FREE_GLOBAL, DEF_FREE_CLASS, DEF_IMPORT, DEF_BOUND,
+     OPT_IMPORT_STAR, OPT_EXEC, OPT_BARE_EXEC, SCOPE_OFF, SCOPE_MASK,
+     FREE, GLOBAL_IMPLICIT, GLOBAL_EXPLICIT)
 
 import weakref
 
@@ -38,15 +39,9 @@ class SymbolTableFactory:
 
 newSymbolTable = SymbolTableFactory()
 
-def is_free(flags):
-    if (flags & (USE | DEF_FREE)) \
-       and (flags & (DEF_LOCAL | DEF_PARAM | DEF_GLOBAL)):
-        return True
-    if flags & DEF_FREE_CLASS:
-        return True
-    return False
 
-class SymbolTable:
+class SymbolTable(object):
+
     def __init__(self, raw_table, filename):
         self._table = raw_table
         self._filename = filename
@@ -59,10 +54,11 @@ class SymbolTable:
             kind = "%s " % self.__class__.__name__
 
         if self._table.name == "global":
-            return "<%sSymbolTable for module %s>" % (kind, self._filename)
+            return "<{0}SymbolTable for module {1}>".format(kind, self._filename)
         else:
-            return "<%sSymbolTable for %s in %s>" % (kind, self._table.name,
-                                                     self._filename)
+            return "<{0}SymbolTable for {1} in {2}>".format(kind,
+                                                            self._table.name,
+                                                            self._filename)
 
     def get_type(self):
         if self._table.type == _symtable.TYPE_MODULE:
@@ -72,7 +68,7 @@ class SymbolTable:
         if self._table.type == _symtable.TYPE_CLASS:
             return "class"
         assert self._table.type in (1, 2, 3), \
-               "unexpected type: %s" % self._table.type
+               "unexpected type: {0}".format(self._table.type)
 
     def get_id(self):
         return self._table.id
@@ -124,6 +120,7 @@ class SymbolTable:
         return [newSymbolTable(st, self._filename)
                 for st in self._table.children]
 
+
 class Function(SymbolTable):
 
     # Default values for instance variables
@@ -148,15 +145,18 @@ class Function(SymbolTable):
 
     def get_globals(self):
         if self.__globals is None:
-            glob = DEF_GLOBAL | DEF_FREE_GLOBAL
-            self.__globals = self.__idents_matching(lambda x:x & glob)
+            glob = (GLOBAL_IMPLICIT, GLOBAL_EXPLICIT)
+            test = lambda x:((x >> SCOPE_OFF) & SCOPE_MASK) in glob
+            self.__globals = self.__idents_matching(test)
         return self.__globals
 
     def get_frees(self):
         if self.__frees is None:
+            is_free = lambda x:((x >> SCOPE_OFF) & SCOPE_MASK) == FREE
             self.__frees = self.__idents_matching(is_free)
         return self.__frees
 
+
 class Class(SymbolTable):
 
     __methods = None
@@ -169,14 +169,17 @@ class Class(SymbolTable):
             self.__methods = tuple(d)
         return self.__methods
 
-class Symbol:
+
+class Symbol(object):
+
     def __init__(self, name, flags, namespaces=None):
         self.__name = name
         self.__flags = flags
+        self.__scope = (flags >> SCOPE_OFF) & SCOPE_MASK # like PyST_GetScope()
         self.__namespaces = namespaces or ()
 
     def __repr__(self):
-        return "<symbol '%s'>" % self.__name
+        return "<symbol {0!r}>".format(self.__name)
 
     def get_name(self):
         return self.__name
@@ -188,8 +191,7 @@ class Symbol:
         return bool(self.__flags & DEF_PARAM)
 
     def is_global(self):
-        return bool((self.__flags & DEF_GLOBAL)
-                    or (self.__flags & DEF_FREE_GLOBAL))
+        return bool(self.__scope in (GLOBAL_IMPLICIT, GLOBAL_EXPLICIT))
 
     def is_vararg(self):
         return bool(self.__flags & DEF_STAR)
@@ -201,12 +203,7 @@ class Symbol:
         return bool(self.__flags & DEF_BOUND)
 
     def is_free(self):
-        if (self.__flags & (USE | DEF_FREE)) \
-            and (self.__flags & (DEF_LOCAL | DEF_PARAM | DEF_GLOBAL)):
-            return True
-        if self.__flags & DEF_FREE_CLASS:
-            return True
-        return False
+        return bool(self.__scope == FREE)
 
     def is_imported(self):
         return bool(self.__flags & DEF_IMPORT)

Lib/test/test_symtable.py

-from test import test_support
-
+"""
+Test the API of the symtable module.
+"""
 import symtable
 import unittest
+import warnings
+
+from test import test_support
+
+
+TEST_CODE = """
+import sys
+
+glob = 42
+
+class Mine:
+    instance_var = 24
+    def a_method(p1, p2):
+        pass
 
+def spam(a, b, *var, **kw):
+    global bar
+    bar = 47
+    x = 23
+    glob
+    def internal():
+        return x
+    return internal
 
-## XXX
-## Test disabled because symtable module needs to be rewritten for new compiler
+def foo():
+    exec 'm'
+    from sys import *
 
-##vereq(symbols[0].name, "global")
-##vereq(len([ste for ste in symbols.values() if ste.name == "f"]), 1)
+def namespace_test(): pass
+def namespace_test(): pass
+"""
+
+
+def find_block(block, name):
+    for ch in block.get_children():
+        if ch.get_name() == name:
+            return ch
 
-### Bug tickler: SyntaxError file name correct whether error raised
-### while parsing or building symbol table.
-##def checkfilename(brokencode):
-##    try:
-##        _symtable.symtable(brokencode, "spam", "exec")
-##    except SyntaxError, e:
-##        vereq(e.filename, "spam")
-##    else:
-##        raise TestFailed("no SyntaxError for %r" % (brokencode,))
-##checkfilename("def f(x): foo)(")  # parse-time
-##checkfilename("def f(x): global x")  # symtable-build-time
 
 class SymtableTest(unittest.TestCase):
-    def test_invalid_args(self):
-        self.assertRaises(TypeError, symtable.symtable, "42")
-        self.assertRaises(ValueError, symtable.symtable, "42", "?", "")
+
+    with test_support.catch_warning(record=False):
+        # Ignore warnings about "from blank import *"
+        warnings.simplefilter("ignore", SyntaxWarning)
+        top = symtable.symtable(TEST_CODE, "?", "exec")
+    # These correspond to scopes in TEST_CODE
+    Mine = find_block(top, "Mine")
+    a_method = find_block(Mine, "a_method")
+    spam = find_block(top, "spam")
+    internal = find_block(spam, "internal")
+    foo = find_block(top, "foo")
+
+    def test_type(self):
+        self.assertEqual(self.top.get_type(), "module")
+        self.assertEqual(self.Mine.get_type(), "class")
+        self.assertEqual(self.a_method.get_type(), "function")
+        self.assertEqual(self.spam.get_type(), "function")
+        self.assertEqual(self.internal.get_type(), "function")
+
+    def test_optimized(self):
+        self.assertFalse(self.top.is_optimized())
+        self.assertFalse(self.top.has_exec())
+        self.assertFalse(self.top.has_import_star())
+
+        self.assertTrue(self.spam.is_optimized())
+
+        self.assertFalse(self.foo.is_optimized())
+        self.assertTrue(self.foo.has_exec())
+        self.assertTrue(self.foo.has_import_star())
+
+    def test_nested(self):
+        self.assertFalse(self.top.is_nested())
+        self.assertFalse(self.Mine.is_nested())
+        self.assertFalse(self.spam.is_nested())
+        self.assertTrue(self.internal.is_nested())
+
+    def test_children(self):
+        self.assertTrue(self.top.has_children())
+        self.assertTrue(self.Mine.has_children())
+        self.assertFalse(self.foo.has_children())
+
+    def test_lineno(self):
+        self.assertEqual(self.top.get_lineno(), 0)
+        self.assertEqual(self.spam.get_lineno(), 11)
+
+    def test_function_info(self):
+        func = self.spam
+        self.assertEqual(func.get_parameters(), ("a", "b", "kw", "var"))
+        self.assertEqual(func.get_locals(),
+                         ("a", "b", "bar", "internal", "kw", "var", "x"))
+        self.assertEqual(func.get_globals(), ("bar", "glob"))
+        self.assertEqual(self.internal.get_frees(), ("x",))
+
+    def test_globals(self):
+        self.assertTrue(self.spam.lookup("glob").is_global())
+        self.assertTrue(self.spam.lookup("bar").is_global())
+        self.assertFalse(self.internal.lookup("x").is_global())
+        self.assertFalse(self.Mine.lookup("instance_var").is_global())
+
+    def test_local(self):
+        self.assertTrue(self.spam.lookup("x").is_local())
+        self.assertFalse(self.internal.lookup("x").is_local())
+
+    def test_referenced(self):
+        self.assertTrue(self.internal.lookup("x").is_referenced())
+        self.assertTrue(self.spam.lookup("internal").is_referenced())
+        self.assertFalse(self.spam.lookup("x").is_referenced())
+
+    def test_parameters(self):
+        for sym in ("a", "var", "kw"):
+            self.assertTrue(self.spam.lookup(sym).is_parameter())
+        self.assertFalse(self.spam.lookup("x").is_parameter())
+
+    def test_symbol_lookup(self):
+        self.assertEqual(len(self.top.get_identifiers()),
+                         len(self.top.get_symbols()))
+
+        self.assertRaises(KeyError, self.top.lookup, "not_here")
+
+    def test_namespaces(self):
+        self.assertTrue(self.top.lookup("Mine").is_namespace())
+        self.assertTrue(self.Mine.lookup("a_method").is_namespace())
+        self.assertTrue(self.top.lookup("spam").is_namespace())
+        self.assertTrue(self.spam.lookup("internal").is_namespace())
+        self.assertTrue(self.top.lookup("namespace_test").is_namespace())
+        self.assertFalse(self.spam.lookup("x").is_namespace())
+
+        self.assert_(self.top.lookup("spam").get_namespace() is self.spam)
+        ns_test = self.top.lookup("namespace_test")
+        self.assertEqual(len(ns_test.get_namespaces()), 2)
+        self.assertRaises(ValueError, ns_test.get_namespace)
+
+    def test_assigned(self):
+        self.assertTrue(self.spam.lookup("x").is_assigned())
+        self.assertTrue(self.spam.lookup("bar").is_assigned())
+        self.assertTrue(self.top.lookup("spam").is_assigned())
+        self.assertTrue(self.Mine.lookup("a_method").is_assigned())
+        self.assertFalse(self.internal.lookup("x").is_assigned())
+
+    def test_imported(self):
+        self.assertTrue(self.top.lookup("sys").is_imported())
+
+    def test_name(self):
+        self.assertEqual(self.top.get_name(), "top")
+        self.assertEqual(self.spam.get_name(), "spam")
+        self.assertEqual(self.spam.lookup("x").get_name(), "x")
+        self.assertEqual(self.Mine.get_name(), "Mine")
+
+    def test_class_info(self):
+        self.assertEqual(self.Mine.get_methods(), ('a_method',))
+
+    def test_filename_correct(self):
+        ### Bug tickler: SyntaxError file name correct whether error raised
+        ### while parsing or building symbol table.
+        def checkfilename(brokencode):
+            try:
+                symtable.symtable(brokencode, "spam", "exec")
+            except SyntaxError as e:
+                self.assertEqual(e.filename, "spam")
+            else:
+                self.fail("no SyntaxError for %r" % (brokencode,))
+        checkfilename("def f(x): foo)(")  # parse-time
+        checkfilename("def f(x): global x")  # symtable-build-time
 
     def test_eval(self):
         symbols = symtable.symtable("42", "?", "eval")

Modules/symtablemodule.c

@@ -81,4 +81,7 @@ init_symtable(void)
 	PyModule_AddIntConstant(m, "GLOBAL_IMPLICIT", GLOBAL_IMPLICIT);
 	PyModule_AddIntConstant(m, "FREE", FREE);
 	PyModule_AddIntConstant(m, "CELL", CELL);
+
+	PyModule_AddIntConstant(m, "SCOPE_OFF", SCOPE_OFF);
+	PyModule_AddIntConstant(m, "SCOPE_MASK", SCOPE_MASK);
 }