Re: how can i hold temporary values in a recursive function

I can only guess what you want, maybe its a closure to memorize the recursive results?

{ my %memo;
  sub rec_func {
    my $key=key_from_input(@_);
    unless (exists $memo{$key}) {
       $memo{$key}=calculate(@_);
    } 
    return $memo{key};
  }
}
[download]

This should effectively cache complicated calculations based on the call-parameters...

(untested)

Of course you are free to decide what you are caching...

Cheers Rolf

Comment on Re: how can i hold temporary values in a recursive function Download Code

Replies are listed 'Best First'.
Re^2: how can i hold temporary values in a recursive function by Corion (Patriarch) on Apr 18, 2010 at 16:51 UTC
For that case, also see Memoize	[reply]
Re^3: how can i hold temporary values in a recursive function by LanX (Saint) on Apr 18, 2010 at 16:59 UTC
I suppose he needs a more general flexibility to memoize based on more complicated input ("Level"?) Thats why I didn't mention Memoize For those interested see Viterbi Algorithm and Algorithm-Viterbi Cheers Rolf	[reply]
Re^4: how can i hold temporary values in a recursive function by Corion (Patriarch) on Apr 18, 2010 at 17:04 UTC
You can pass a key-generator function to Memoize in case you need to normalize your parameters. Personally, I would add the "level" as another parameter and use plain Memoize.	[reply]
Re^5: how can i hold temporary values in a recursive function by LanX (Saint) on Apr 18, 2010 at 17:14 UTC