On 2017-06-18 22:38, Alireza Rafiei wrote:
Hi all,
I'm not sure whether this idea has been discussed before or not, so I
apologize in advanced if that's the case.
Consider the behavior:
>>> f = lambda: True
>>> f.__name__
'<lambda>'
>>> x = f
>>> x.__name__
'<lambda>'
I'm arguing the behavior above is too brittle/limited and, considering
that the name of the attribute is `__name__`, not entirely consistent
with Python's AST. Consider:
>>> f = lambda: True
>>> x = f
At the first line, an ast.Assign would be created whose target is an
ast.Name whose `id` is `f`.
At the second line, an ast.Assign would be created whose target is an
ast.Name whose `id` is `x`.
However, as you can see `__name__` special method returns 'lambda' in
both cases (just like it was defined
https://docs.python.org/3/library/stdtypes.html#definition.__name__),
whereas I think either it should have returned '<lambda>' and 'x' or a
new function/attribute should exist that does so and more.
For example, consider:
>>> x_1 = 1
>>> x_2 = 1
>>> x_3 = 1
>>> x_4 = x_1
>>> for i in [x_1, x_2, x_3, x_4]:
>>> print(i)
1
1
1
1
Now assume such a function exist and is called `name`. Then:
>>> name(1)
'1'
>>> name("Something")
"Something"
>>> name(x_1)
'x_1'
>>> name(x_4)
'x_4'
>>> name(x_5)
'x_5' # Or an Exception!
>>> def itername(collection):
>>> for i in map(lambda x: name(x), collection):
>>> yield i
>>>
>>> for i in [x_1, x_2, x_3, x_4]:
>>> print(i, name(i))
1, 'i'
1, 'i'
1, 'i'
1, 'i'
>>> for i in itername([x_1, x_2, x_3, x_4]):
>>> print(i)
'x_1'
'x_2'
'x_3'
'x_4'
[snip]
That's not correct.
Look at the definition of 'itername'. The lambda returns the result of
name(x), which is 'x'.
Therefore, the correct result is:
'x'
'x'
'x'
'x'
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