[Python-ideas] Where-statement (Proposal for function expressions)

[Terry Reedy]

> To my eyes, the first is harder to read than the second one.  Of
> course I can do this:
> 
>     f = self.someobject.get_generator()
>     g = self.important_test
>     mylist =  [item in f if g(item)]:
> 
> but then "f" and "g" pollute the calling context's namespace.

So what? Seriously, what harm does a temporary association do? 
Especially when one can easily 'clean up' with 'del f,g' if it actually 
make a functional difference or if one just wants to cater to an obsession.

In particular, why is this reason to *PERMANENTLYT pollute the language 
with an otherwise useless new feature?

Unlike namespace associations, deleting language features is really 
difficult.

Terry Jan Reedy