better lambda support in the future?

Jeff Shannon jeff at ccvcorp.com
Sat Dec 18 02:24:59 CET 2004


Steven Bethard wrote:

> Jeff Shannon wrote:
>
>> It occurs to me that, in a statically compiled language, function 
>> definitions all happen before the program starts, and thus that 
>> definition can't be affected by other variables (i.e. an outer 
>> function's parameters).
>
>
> I think you might be confusing static compilation in a language with 
> lack of first-class functions in a language.  


Hm, possibly.  I must confess that my direct knowledge is limited to a 
fairly narrow set of languages, and that C and C++ are the only 
statically-compiled languages I've used.  Still, I'm not sure that it's 
just a matter of functions as first-class objects.  Would OCaml (or some 
other static language) have something that's equivalent to this?

def f(x):
    if x < 0:
        def g(y):
            return y * -1
    else:
        def g(y):
            return y
    return g

foo = f(1)

Here, nested scopes are not enough.  Only one of these functions is 
created, and which one that is depends on the run-time value of the 
function parameter.  A compiler couldn't know this ahead of time.  I 
suppose it might be able to do something by compiling both of them, 
(though I'm not sure how it'd track two different functions with the 
same name in the same namespace...) but that seems a bit questionable to 
me...

Jeff Shannon
Technician/Programmer
Credit International






More information about the Python-list mailing list