Anti-poking lobby (was:Re: [Types-sig] type declaration syntax)

[John Machin]

Skip said:
> 
>     skaller> I.e. TWO bans fix most problems. The ban on module level
>     skaller> rebindings is a significant restriction. 
> 
> I'll say.  The common idiom for trapping stdout or stderr is to rebind
> sys.stdout/stderr to a file-like object.  How would that be accomplished
> in such a straightforward way if module-level rebindings are disallowed?
> 

sys.stdout = "you lose"

is a bit too straightforward for my liking.

Once we have banned poking from outside a module, can't we fix the 
presumably-few cases of missing-but-required functionality by supplying 
functions? For example,

previous_stdout = sys.divert_stdout(new_stdout_file-like_object)

[default argument is original stdout]

with maybe some checking as determined by the module's "owner" [is it 
truly file-like?], and maybe some extra functionality e.g.

sys.divert_stdout("my_stdout.log")

# interprets string as name of file; appends if existing, else creates