New submission from Ugra Dániel <[email protected]>:
In some cases it would be really helpful to have a decorator which
automagically casts returned value to a different type.
Particularly, instead of writing something like this:
def example():
result = []
for ...:
result.append(item)
return result
...this would do the magic:
@functools.cast(list)
def example():
for ...:
yield item
On the positive side (apart from its compactness) when an implementation
changes from list to set, .append() does not need to be changed to .add().
Of course on the caller side one can always write list(example()) but sometimes
this transformation needs to be done on implementation side for architectural
reasons.
Pseudocode for proposed functools.cast():
def cast(type):
def wrapper(func):
@wraps(func)
def newfunc(*args, **keywords):
return type(func(*args, **keywords))
return newfunc
return wrapper
----------
components: Library (Lib)
messages: 357640
nosy: daniel.ugra
priority: normal
severity: normal
status: open
title: Add a new functools.cast() function
type: enhancement
versions: Python 3.9
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Python tracker <[email protected]>
<https://bugs.python.org/issue38940>
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