[Python-Dev] Terminology for PEP 343

[Ron Adam]

Nick Coghlan wrote:
> Raymond Hettinger wrote:
> 
>>Whatever term is selected, it should be well thought-out and added to
>>the glossary.  The choice of words will likely have a great effect on
>>learnability and on how people think about the new tool.

I tried to bring this up on python-list, but I didn't get much of a 
response.  I suggested "witherator" as a too cute alternative, but was 
hoping to get some alternatives to that.

   http://mail.python.org/pipermail/python-list/2005-June/286684.html

> For 'with' statements, all we really know is that the object may do 
> something before the suite it is entered, and something else as the 
> suite is exited. Other than that, it could be (or do) anything. Hence, 
> 'user defined statement'.

I would say the key attribute is the "and something else as the suite is 
exited" part.  With out that, the "with" statement isn't needed and a 
regular function or generator would work.

A term which stresses finalizing may be appropriate.


> With that piece of terminology in place, the natural outcome was to 
> call objects that supplied __enter__ and __exit__ methods "statement 
> templates".

Will objects be created that can be used with and without "with" 
statements?  I think that this could be a source of confusion.

It seems to me that "with" statements require a "with" object, and that 
those objects probably shouldn't be used without the "with" statement. 
Having a clear separation might be a good idea.

Should there be a "with" (different name most likely) type?

Would there be any advantages of a "with" base object that can have 
constructor methods that can accept either a try-finally generator or 
two functions to insert into the __enter__ and __exit__ methods as 
arguments?

For example, call a with object a "manage" object then:

    with manage.generator(open_file_gen) as f:
        BLOCK

    with manage.enter_exit(lock_func, unlock_func) as lock:
        BLOCK



> I also used this term to come up with PEP 346's name for the generator 
> to statement template conversion decorator: "stmt_template"
 >
> (Like others, the fact that 'with' is a verb makes it very hard for me 
> to interpret "with_template" correctly when I see it as a decorator - 
> I always want to ask "with which template?")

I agree, the decorator adds a layer of complexity to it. I think the 
with-generator behavior needs to be described without the decorator 
version first, then the decorator becomes syntactic sugar to make it 
easier to do the same thing.

Ron