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Re: self-feeding infinite loop

by stvn (Monsignor)
on Aug 18, 2007 at 16:46 UTC ( [id://633501]=note: print w/replies, xml ) Need Help??


in reply to self-feeding infinite loop

Honestly, this is so not the way you want to do an infinite list. I won't even get into the why (other responders already have), and Google can tell you the details of it better than I can anyway (although maybe not perl-specific, but the theory at least).

The following is the more commonly accepted way to go about such a thing.

my $counter = 0; my $generator = sub { ++$counter }; while (1) { print $generator->(); }
To re-do your example it would be this:
my $gimme_an_A = sub { 'a' }; while (1) { print $gimme_an_A->(); }
Your approach is very memory wasteful since you have an infinitely growing @array, which will eventually consume all available system memory. The above versions never store previous values (which I can only assume you are never using anyway) so they can run in a pretty small and compact memory space.

-stvn

Replies are listed 'Best First'.
Re^2: self-feeding infinite loop
by Anonymous Monk on Aug 19, 2007 at 07:39 UTC
    mark jason dominus wrote a very good, perl-specific book about this `generator' or `iterator' technique: Higher-Order Perl

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