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Re: Tail-recursion in perl?!

by Tanktalus (Canon)
on Jul 09, 2005 at 14:55 UTC ( [id://473685]=note: print w/replies, xml ) Need Help??


in reply to Tail-recursion in perl?!

I think this is what you want:

#! perl -w use strict; use diagnostics; use Carp; sub iterFac { my $max = shift; my $val = shift || 1; my $cnt = shift || 1; Carp::cluck("we are currently here:"); return $val if $cnt > $max; #iterFac($max, $val*$cnt, ++$cnt); @_ = ($max, $val*$cnt, ++$cnt); goto &iterFac; } my $x = iterFac(5); print "Factorial 5 = $x\n";
Note how I've used Carp::cluck to show where we are at all times. If you remove the # from the iterFac call and comment out the @_ assignment and the goto, and run this, you'll see how it cluck's that it gets 5 subroutine calls deep. But as-is, the cluck always shows only a single subroutine deep.

I think that's what you're looking for, but someone with an actual CS degree may show me wrong ;-)

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