Re: delay and force in Python

[Benji York]

Will Stuyvesant wrote:
Streams are interesting because they are to lists like
xrange is to range.  Could save a lot on memory and
computations.
I think you're looking for generators.
Below is my straight translation from Scheme code in the
Wizard book to Python.

Something else: this crashes with a "maximum recursion reached"
. print stream_enumerate_interval(1,998)
Unlike Scheme, Python isn't designed for heavily recursive algorithms. 
Here's a more Pythonic equivalent of your code:

def count(start, stop):
    i = start
    while i < stop:
        yield i
        i += 1
def even(gen):
    for x in gen:
        if x % 2 == 0:
            yield x
numbers = even(count(1, 999))
first = numbers.next()
second = numbers.next()
print second
--
Benji York
[EMAIL PROTECTED]
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