Draft Pep (was: Re: Let's Talk About Lambda Functions!)
fakeaddress at nowhere.org
Wed Aug 7 08:27:11 CEST 2002
John Roth wrote:
> "Bryan Olson" wrote:
>>Pure Python modules don't get their names from
>>Python code, but from the file in which they're stored. As for the
>>assignment to a variable, I would rather use:
>> varname = import filename
>>to make the semantics clear.
> The trouble with this is that Python maintains an internal dictionary
> of modules, by name. So
> import filename
> not only puts filename in the current module namespace,
> but also puts it in the dictionary. That's not at all the same
> thing as
> foobar = import snafu
I don't see that. What the import does is the internal stuff, and
it returns a module. That value, the module, gets stored in foobar,
just as any other type of value gets assigned to a variable.
>>Using a special construct suggests something else is
> As has been discussed, there is something else going on. The name
> is bound to the module so it can be accessed by introspection. Never
> having used this feature, I'm not certain of how essential it is.
That something else is irrelevent to the assignment of a value to a
variable. Do the something else in the special construct. Do the
assignment with the assignment operator.
>>I've never seen a
>>Python-based text on the level of Abelson and Sussman's /Structure and
>>Interpretation of Computer Programs/ or Friedman, Wand and Haynes'
>>/Essentials of Programming Languages/.
> I think the point here is that of usability for teaching computer
> science in general, not for the ability to teach Python.
Yes, absolutely. That's the point I've been trying to make.
>> Who said adding list comprehensions was wrong? The point is that
>> 'need' is not really the issue. I could just as easily say that recent
>> additions to Perl alleviate the need for Python. The language would
>> be better with a full lambda, that's all.
> I don't think that list comprehensions have anything to do with the
Once again we find ourselves in agreement. I don't think the recent
additions have any impact on the importance of a full lambda.
> Extending lambda has been discussed many times, and has never gotten
> past the discussion stage because implementing def in expression format
> is simply too much of a change to the language. Just to mention one
> of the issues: how do you do a clean if/else/elif syntax in an
> expression format?
That seems like a silly issue. Either don't require lambda to operate
only on expressions, as in, for example, Perl, or make the construct an
expression, as in, for example, various Lisps.
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