[Python-ideas] Modern language design survey for "assign and compare" statements

[Juancarlo Añez]

> > print(child_pid)  # child_pid is undefined
>
> Why on earth would it be undefined?
>

Indeed, users would expect the new uses of "as" to behave as the previous
ones. The problem is that "with"  and "except" do things differently:

In [*1*]: *import* *os*


In [*2*]: *with* open(os.path.expanduser('~/tmp/xx')) *as* f:

   ...:     *pass*

   ...:


In [*3*]: print(f)

<_io.TextIOWrapper name='/Users/apalala/tmp/xx' mode='r' encoding='UTF-8'>


In [*4*]: *try*:

   ...:     print('ok')

   ...:     *raise* *Exception*()

   ...: *except* *Exception* *as* e:

   ...:     *pass*

   ...:


In [*5*]: print(e)

---------------------------------------------------------------------------

NameError                                 Traceback (most recent call last)

<ipython-input-5-bb2ea196f768> in <module>()

----> 1 print(e)


NameError: name 'e' is not defined



> Anyway, if you want to propose an alternative to PEP 572, you ought to
> write your own competing PEP.
>

I don't take that as a challenge. It would be good to have different, maybe
somewhat competing PEPs. It's been done before.


-- 
Juancarlo *Añez*
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