From 2498d9e96834bb21b5c8bb55c81f311a2760ea7a Mon Sep 17 00:00:00 2001 From: Ethan Furman Date: Fri, 18 Oct 2013 00:45:40 -0700 Subject: [PATCH] Issue #19272: slight clarification of pickle docs with regard to lambda. --- Doc/library/pickle.rst | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/Doc/library/pickle.rst b/Doc/library/pickle.rst index 0354a3013db..3bdbcf941bc 100644 --- a/Doc/library/pickle.rst +++ b/Doc/library/pickle.rst @@ -384,7 +384,8 @@ The following types can be pickled: * tuples, lists, sets, and dictionaries containing only picklable objects -* functions defined at the top level of a module +* functions defined at the top level of a module (using :keyword:`def`, not + :keyword:`lambda`) * built-in functions defined at the top level of a module @@ -402,7 +403,7 @@ raised in this case. You can carefully raise this limit with :func:`sys.setrecursionlimit`. Note that functions (built-in and user-defined) are pickled by "fully qualified" -name reference, not by value. This means that only the function name is +name reference, not by value. [#]_ This means that only the function name is pickled, along with the name of the module the function is defined in. Neither the function's code, nor any of its function attributes are pickled. Thus the defining module must be importable in the unpickling environment, and the module @@ -850,6 +851,9 @@ The following example reads the resulting pickled data. :: .. [#] Don't confuse this with the :mod:`marshal` module +.. [#] This is why :keyword:`lambda` functions cannot be pickled: all + :keyword:`lambda` functions share the same name: ````. + .. [#] The exception raised will likely be an :exc:`ImportError` or an :exc:`AttributeError` but it could be something else.