[Python-checkins] r84792 - in python/branches/py3k: Doc/library/reprlib.rst Lib/collections.py Lib/reprlib.py Lib/test/test_reprlib.py Misc/NEWS
raymond.hettinger
python-checkins at python.org
Mon Sep 13 23:36:00 CEST 2010
Author: raymond.hettinger
Date: Mon Sep 13 23:36:00 2010
New Revision: 84792
Log:
Issue 9840: Add reprlib.recursive_repr(), a decorator for handling recursive calls to __repr__ methods.
Modified:
python/branches/py3k/Doc/library/reprlib.rst
python/branches/py3k/Lib/collections.py
python/branches/py3k/Lib/reprlib.py
python/branches/py3k/Lib/test/test_reprlib.py
python/branches/py3k/Misc/NEWS
Modified: python/branches/py3k/Doc/library/reprlib.rst
==============================================================================
--- python/branches/py3k/Doc/library/reprlib.rst (original)
+++ python/branches/py3k/Doc/library/reprlib.rst Mon Sep 13 23:36:00 2010
@@ -34,6 +34,29 @@
similar to that returned by the built-in function of the same name, but with
limits on most sizes.
+In addition to size-limiting tools, the module also provides a decorator for
+detecting recursive calls to :meth:`__repr__` and substituting a placeholder
+string instead.
+
+.. decorator:: recursive_repr(fillvalue="...")
+
+ Decorator for :meth:`__repr__` methods to detect recursive calls within the
+ same thread. If a recursive call is made, the *fillvalue* is returned,
+ otherwise, the usual :meth:`__repr__` call is made. For example:
+
+ >>> class MyList(list):
+ ... @recursive_repr()
+ ... def __repr__(self):
+ ... return '<' + '|'.join(map(repr, self)) + '>'
+ ...
+ >>> m = MyList('abc')
+ >>> m.append(m)
+ >>> m.append('x')
+ >>> print(m)
+ <'a'|'b'|'c'|...|'x'>
+
+ .. versionadded:: 3.2
+
.. _repr-objects:
Modified: python/branches/py3k/Lib/collections.py
==============================================================================
--- python/branches/py3k/Lib/collections.py (original)
+++ python/branches/py3k/Lib/collections.py Mon Sep 13 23:36:00 2010
@@ -13,6 +13,7 @@
import heapq as _heapq
from weakref import proxy as _proxy
from itertools import repeat as _repeat, chain as _chain, starmap as _starmap
+from reprlib import recursive_repr as _recursive_repr
################################################################################
### OrderedDict
@@ -43,7 +44,6 @@
'''
if len(args) > 1:
raise TypeError('expected at most 1 arguments, got %d' % len(args))
- self.__in_repr = False # detects recursive repr
try:
self.__root
except AttributeError:
@@ -97,10 +97,10 @@
def __reduce__(self):
'Return state information for pickling'
items = [[k, self[k]] for k in self]
- tmp = self.__map, self.__root, self.__in_repr
- del self.__map, self.__root, self.__in_repr
+ tmp = self.__map, self.__root
+ del self.__map, self.__root
inst_dict = vars(self).copy()
- self.__map, self.__root, self.__in_repr = tmp
+ self.__map, self.__root = tmp
if inst_dict:
return (self.__class__, (items,), inst_dict)
return self.__class__, (items,)
@@ -167,18 +167,12 @@
items = MutableMapping.items
__ne__ = MutableMapping.__ne__
+ @_recursive_repr()
def __repr__(self):
'od.__repr__() <==> repr(od)'
if not self:
return '%s()' % (self.__class__.__name__,)
- if self.__in_repr:
- return '...'
- self.__in_repr = True
- try:
- result = '%s(%r)' % (self.__class__.__name__, list(self.items()))
- finally:
- self.__in_repr = False
- return result
+ return '%s(%r)' % (self.__class__.__name__, list(self.items()))
def copy(self):
'od.copy() -> a shallow copy of od'
Modified: python/branches/py3k/Lib/reprlib.py
==============================================================================
--- python/branches/py3k/Lib/reprlib.py (original)
+++ python/branches/py3k/Lib/reprlib.py Mon Sep 13 23:36:00 2010
@@ -1,9 +1,38 @@
"""Redo the builtin repr() (representation) but with limits on most sizes."""
-__all__ = ["Repr","repr"]
+__all__ = ["Repr", "repr", "recursive_repr"]
import builtins
from itertools import islice
+try:
+ from _thread import get_ident
+except AttributeError:
+ from _dummy_thread import get_ident
+
+def recursive_repr(fillvalue='...'):
+ 'Decorator to make a repr function return fillvalue for a recursive call'
+
+ def decorating_function(user_function):
+ repr_running = set()
+
+ def wrapper(self):
+ key = id(self), get_ident()
+ if key in repr_running:
+ return fillvalue
+ repr_running.add(key)
+ try:
+ result = user_function(self)
+ finally:
+ repr_running.discard(key)
+ return result
+
+ # Can't use functools.wraps() here because of bootstrap issues
+ wrapper.__module__ = getattr(user_function, '__module__')
+ wrapper.__doc__ = getattr(user_function, '__doc__')
+ wrapper.__name__ = getattr(user_function, '__name__')
+ return wrapper
+
+ return decorating_function
class Repr:
Modified: python/branches/py3k/Lib/test/test_reprlib.py
==============================================================================
--- python/branches/py3k/Lib/test/test_reprlib.py (original)
+++ python/branches/py3k/Lib/test/test_reprlib.py Mon Sep 13 23:36:00 2010
@@ -11,6 +11,7 @@
from test.support import run_unittest
from reprlib import repr as r # Don't shadow builtin repr
from reprlib import Repr
+from reprlib import recursive_repr
def nestedTuple(nesting):
@@ -301,10 +302,38 @@
def __repr__(self):
raise Exception("This should be caught by Repr.repr_instance")
+class MyContainer:
+ 'Helper class for TestRecursiveRepr'
+ def __init__(self, values):
+ self.values = list(values)
+ def append(self, value):
+ self.values.append(value)
+ @recursive_repr()
+ def __repr__(self):
+ return '<' + ', '.join(map(str, self.values)) + '>'
+
+class MyContainer2(MyContainer):
+ @recursive_repr('+++')
+ def __repr__(self):
+ return '<' + ', '.join(map(str, self.values)) + '>'
+
+class TestRecursiveRepr(unittest.TestCase):
+ def test_recursive_repr(self):
+ m = MyContainer(list('abcde'))
+ m.append(m)
+ m.append('x')
+ m.append(m)
+ self.assertEqual(repr(m), '<a, b, c, d, e, ..., x, ...>')
+ m = MyContainer2(list('abcde'))
+ m.append(m)
+ m.append('x')
+ m.append(m)
+ self.assertEqual(repr(m), '<a, b, c, d, e, +++, x, +++>')
def test_main():
run_unittest(ReprTests)
run_unittest(LongReprTest)
+ run_unittest(TestRecursiveRepr)
if __name__ == "__main__":
Modified: python/branches/py3k/Misc/NEWS
==============================================================================
--- python/branches/py3k/Misc/NEWS (original)
+++ python/branches/py3k/Misc/NEWS Mon Sep 13 23:36:00 2010
@@ -52,6 +52,9 @@
Library
-------
+- Issue 9840: Added a decorator to reprlib for wrapping __repr__ methods
+ to make them handle recursive calls within the same thread.
+
- logging: Enhanced HTTPHandler with secure and credentials initializers.
- Issue #767645: Set os.path.supports_unicode_filenames to True on Mac OS X
More information about the Python-checkins
mailing list