[Python-Dev] Extended Function syntax

[Just van Rossum]

Samuele Pedroni wrote:

> a thunk is like a Smalltalk block, a closure that can rebind the
> locals and can get arguments ( (line): above) ), and maybe non-local
> returns ( ^ in Smalltalk): in pseudo-python the above is:
> 
> count = 0
> defClosureAllowingRebinding  _thunk(line):
>     if line.find('Python') >=0:
>       count += 1
>       print line,
> 
> iterclose(open('blah.txt'))(_thunk)

If _rebinding_ is what we're after, then why not go all the way an
introduce a rebind operator? Say ':='. Augmented assignment would also
become rebinding then (hm, I hear the sound of code breaking in the
distance ;-) Add that to MWH's function/class filter patch and you can
write:

    count = 0
    def _thunk(line) [iterclose(open('blah.txt'))]:
        if line.find('Python') >=0:
            count += 1  # or count := count + 1
            print line,

Not nice that _thunk needs to be named, but perhaps the function name
can become optional:

    count = 0
    def (line) [iterclose(open('blah.txt'))]:
        if line.find('Python') >=0:
            count += 1
            print line,

How's that for a change of direction? ;-)

I'm just throwing in an idea, I'm not saying I like this (I don't know
yet).

Just