Bugs item #1153622, was opened at 2005-02-28 17:48
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Category: Parser/Compiler
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Submitted By: Mattias Engdegård (yorick)
Assigned to: Nobody/Anonymous (nobody)
Summary: eval does not bind variables in lambda bodies correctly
Initial Comment:
eval() does not bind variables in lambda expressions
correctly:
>>>def f(g): return eval('lambda x: g(x)')
>>>f(lambda y: y * 2)(17)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "<string>", line 1, in <lambda>
NameError: global name 'g' is not defined
The docs say this about eval():
# If both dictionaries are omitted, the expression is
# executed in the environment where eval is called.
and using plain local variables work as expected:
>>>def h(d): return eval('d(10)')
>>>h(lambda y: y * 2)
20
Also, if locals() is presented as the global dict to
eval(), it works:
>>>def f(g): return eval('lambda x: g(x)', locals(),
locals())
>>>f(lambda y: y * 2)(17)
34
but this does not allow the expression to reference
global variables of course.
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