New submission from Nathan West:
A common Python idiom is to test objects by value in an if. This includes
container emptiness and regular expression matches, or using 'or' to specify a
default value:
if my_list:
# list isn't empty
if regex.match(string):
# string matched the regex
my_list = arg or [1,2,3]
It'd be nice if we could use this idiom with inspect.Signature._empty or
inspect.Parameter.empty:
sig = signature(func)
for param in sig.parameters.values():
if param.annotation:
...
or, to use a the example that motivated this idea:
def arg_type(param):
return param.annotation or str
The only issue I can think of is that, if an annotation or default value is
some False value, like None, than the test will fail even if the value isn't
_empty. However, this issue already exists for other uses of this idiom, and I
think this is a perfect extension of the form.
----------
components: Library (Lib)
messages: 237987
nosy: Lucretiel
priority: normal
severity: normal
status: open
title: Make inspect._empty test to False
type: enhancement
versions: Python 3.5
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Python tracker <[email protected]>
<http://bugs.python.org/issue23653>
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