Yes you are right, if you just want to carry an expression around then lambda does it; but delay was not intended as a top-level function. Perhaps you think that my silly stream implementation in the original post builds the whole list, but it does not:
>>> o = stream_enumerate_interval(11,121) >>> print o [11, <function <lambda> at 0x00BA8670>] >>> f = o[1] >>> r = f() >>> print r [12, <function <lambda> at 0x00BA86B0>] instead it builds a list of lambda's, and that is so desirable <wink> Others suggested generators indeed, and I can imagine now a usage pattern like >>> s = stream_generator(initValue, next, stop, other_params) >>> stream_hd(stream_tl(stream_filter(isEven,s))) where the idea is to pass a generator to a function all the time. What I don't like though is that I then, as I understand it, have to code some for-loop inside that function, I try to avoid for-loops. But a functional form defined with a for-loop does not seem all that bad. Anyway I have some reading-up to do, about things some posters use and I forgot to keep up with since I have been coding Python 1.5.2 style for ages now: properties, itertools, ...printed some stuff already, thanks! -- http://mail.python.org/mailman/listinfo/python-list
