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Re: sub and anonymous sub

by rinceWind (Monsignor)
on Jun 21, 2002 at 12:59 UTC ( #176268=note: print w/replies, xml ) Need Help??

in reply to sub and anonymous sub

Interestingly, I thinkl there is a cleaner way to do it. My experience of other programming languages is showing. The algorithm you have given is non-reentrant, hence non-threadsafe.

Instead, I prefer passing in a level number to recurse, which means that separate threads calling recurse will not interfere with one another.

#(1) sub recurse { #(2) my ($depth) = @_; print +(" .") x $depth . "current depth:$depth\n" ; recurse($depth + 1) if $depth < 3; print +(" .") x $depth . "current depth:$depth\n" ; } #(3) #(4) recurse(0); # (5)
I know perl is not thread safe, but perl 6 and/or perl 5.x might be.

My $0.02 --rW

Update: Gerbil is right. I don't need the extra braces. This is what comes with cutting and pasting someone else's example rather than rewriting from scratch.

Have edited the example to take on Gerbil's suggestions

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Re: Re: sub and anonymous sub
by Gerbil (Initiate) on Jun 21, 2002 at 22:39 UTC
    I am far away from being a mighty Perl hacker, but I've done recursion depth counting this way all the time. It's "cleaner" because you don't have to understand Perl-specific techniques. And it's thread-safe, too? Cool ;) Didn't know that... But why keep the curly brackets?
    sub recurse { my ($depth) = @_; print +(" .") x $depth . "current depth:$depth\n" ; recurse($depth + 1) if $depth < 3; print +(" .") x $depth . "current depth:$depth\n" ; } recurse(-1);
    This is the same, right? Additionally, I would start with recurse(0);

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