Why is "while" ticking me off???

[Alex Martelli]

"Steve Lamb" <grey at despair.rpglink.com> wrote in message
news:slrn8tq8sp.aj6.grey at teleute.rpglink.com...
> On Thu, 05 Oct 2000 19:58:25 -0400, Thomas Gagne <tgagne at ix.netcom.com>
wrote:
> >while line = fp.readline():
> >    do something with 'line'
>
>     Perlism?
>
> >I'm obviously not approaching this in the Python idiomatic way.
>
> while 1:
>   line = fp.readline()
>   if not line:
>     break
>   do something with 'line'

Yes, this is canonical, but it's one of the few things I dislike
in Python.  I much prefer a wrap-into-a-sequence approach -- I
have in my site.py this definition:

class lazyseq:
    def __init__(self, func, termtest=None):
        self.func=func
        self.term=termtest
        if not self.term:
            self.term = lambda x, y: not x
    def __getitem__(self, index):
        item = self.func()
        if self.term(item, index): raise IndexError
        return item

which lets me do

    for line in lazyseq(fp.readline):
        do something with line


For a more general approach to introducing functional programming
idioms (laziness in particular) into Python, see functional.py at:

http://sourceforge.net/projects/xoltar-toolkit/


Alex