bpo-34983: Expose symtable.Symbol.is_nonlocal() in the symtable module (GH-9872)

The symbol table was not exposing functionality to query the nonlocal symbols
in a function or to check if a particular symbol is nonlocal.
This commit is contained in:
Pablo Galindo 2018-10-20 01:46:00 +01:00 committed by GitHub
parent 6395844e6a
commit d5b4f1b5a0
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5 changed files with 36 additions and 3 deletions

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@ -105,6 +105,10 @@ Examining Symbol Tables
Return a tuple containing names of globals in this function.
.. method:: get_nonlocals()
Return a tuple containing names of nonlocals in this function.
.. method:: get_frees()
Return a tuple containing names of free variables in this function.
@ -144,6 +148,10 @@ Examining Symbol Tables
Return ``True`` if the symbol is global.
.. method:: is_nonlocal()
Return ``True`` if the symbol is nonlocal.
.. method:: is_declared_global()
Return ``True`` if the symbol is declared global with a global statement.

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@ -1,7 +1,7 @@
"""Interface to the compiler's internal symbol tables"""
import _symtable
from _symtable import (USE, DEF_GLOBAL, DEF_LOCAL, DEF_PARAM,
from _symtable import (USE, DEF_GLOBAL, DEF_NONLOCAL, DEF_LOCAL, DEF_PARAM,
DEF_IMPORT, DEF_BOUND, DEF_ANNOT, SCOPE_OFF, SCOPE_MASK, FREE,
LOCAL, GLOBAL_IMPLICIT, GLOBAL_EXPLICIT, CELL)
@ -117,6 +117,7 @@ class Function(SymbolTable):
__locals = None
__frees = None
__globals = None
__nonlocals = None
def __idents_matching(self, test_func):
return tuple(ident for ident in self.get_identifiers()
@ -141,6 +142,11 @@ class Function(SymbolTable):
self.__globals = self.__idents_matching(test)
return self.__globals
def get_nonlocals(self):
if self.__nonlocals is None:
self.__nonlocals = self.__idents_matching(lambda x:x & DEF_NONLOCAL)
return self.__nonlocals
def get_frees(self):
if self.__frees is None:
is_free = lambda x:((x >> SCOPE_OFF) & SCOPE_MASK) == FREE
@ -184,6 +190,9 @@ class Symbol(object):
def is_global(self):
return bool(self.__scope in (GLOBAL_IMPLICIT, GLOBAL_EXPLICIT))
def is_nonlocal(self):
return bool(self.__flags & DEF_NONLOCAL)
def is_declared_global(self):
return bool(self.__scope == GLOBAL_EXPLICIT)

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@ -10,6 +10,7 @@ TEST_CODE = """
import sys
glob = 42
some_var = 12
class Mine:
instance_var = 24
@ -19,10 +20,15 @@ class Mine:
def spam(a, b, *var, **kw):
global bar
bar = 47
some_var = 10
x = 23
glob
def internal():
return x
def other_internal():
nonlocal some_var
some_var = 3
return some_var
return internal
def foo():
@ -47,6 +53,7 @@ class SymtableTest(unittest.TestCase):
a_method = find_block(Mine, "a_method")
spam = find_block(top, "spam")
internal = find_block(spam, "internal")
other_internal = find_block(spam, "other_internal")
foo = find_block(top, "foo")
def test_type(self):
@ -75,12 +82,12 @@ class SymtableTest(unittest.TestCase):
def test_lineno(self):
self.assertEqual(self.top.get_lineno(), 0)
self.assertEqual(self.spam.get_lineno(), 11)
self.assertEqual(self.spam.get_lineno(), 12)
def test_function_info(self):
func = self.spam
self.assertEqual(sorted(func.get_parameters()), ["a", "b", "kw", "var"])
expected = ["a", "b", "internal", "kw", "var", "x"]
expected = ['a', 'b', 'internal', 'kw', 'other_internal', 'some_var', 'var', 'x']
self.assertEqual(sorted(func.get_locals()), expected)
self.assertEqual(sorted(func.get_globals()), ["bar", "glob"])
self.assertEqual(self.internal.get_frees(), ("x",))
@ -93,6 +100,12 @@ class SymtableTest(unittest.TestCase):
self.assertFalse(self.internal.lookup("x").is_global())
self.assertFalse(self.Mine.lookup("instance_var").is_global())
def test_nonlocal(self):
self.assertFalse(self.spam.lookup("some_var").is_nonlocal())
self.assertTrue(self.other_internal.lookup("some_var").is_nonlocal())
expected = ("some_var",)
self.assertEqual(self.other_internal.get_nonlocals(), expected)
def test_local(self):
self.assertTrue(self.spam.lookup("x").is_local())
self.assertFalse(self.internal.lookup("x").is_local())

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@ -0,0 +1,2 @@
Expose :meth:`symtable.Symbol.is_nonlocal` in the symtable module. Patch by
Pablo Galindo.

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@ -84,6 +84,7 @@ PyInit__symtable(void)
return NULL;
PyModule_AddIntMacro(m, USE);
PyModule_AddIntMacro(m, DEF_GLOBAL);
PyModule_AddIntMacro(m, DEF_NONLOCAL);
PyModule_AddIntMacro(m, DEF_LOCAL);
PyModule_AddIntMacro(m, DEF_PARAM);
PyModule_AddIntMacro(m, DEF_FREE);