Hi.
It would be great to be able to reverse usage/definition parts in haskell-way with "where" keyword. Since Python 3 would miss lambda, that would be extremly useful for creating readable sources.
Usage could be something like:
>>> res = [ f(i) for i in objects ] where: >>> def f(x): >>> #do something
I don't know haskell, but it looks SQL-ish to me (only by loose association). And it's not that unpythonic - it resembles
>>> res = [x for x in sequence if x.isOk()]
or
>>> print words[3], words[5] where: >>> words = input.split()
Here's a shorter version:
>>> print input.split()[3:5:2]
(Does it qualify as obfuscated Python code? :) )
- defining variables in "where" block would restrict their visibility to one expression
- it's more easy to read sources when you know which part you can skip,
Yes, I like the readability of it, too.
compare to
>>> def f(x): >>> #do something >>> res = [ f(i) for i in objects ]
in this case you read definition of "f" before you know something about it usage.
When I first read your post, I thought "Well, just one more of those Py3k ideas that appear on c.l.py every day." But as I look at the latter example, I think you have just scratched my itch. The same thing has bugged me more than once in my code.
I think this idea is of the same kind as the @decorator syntax. Guido moved an operation to a point in the code where it was more visible. You moved an operation to a more local context where (pun not intended) it really belongs.
I'm usually rather conservative about Python syntax (@decorators, absolute/relative imports, if-else operator), but this one could appear in Python tomorrow and that would be too far in the future for me ;)
Cheers,
AdSR -- http://mail.python.org/mailman/listinfo/python-list
