Permutations - Perl or just Javascript embedded ?

[Telemach]

Yesterday I was thinking all day long about what to use for
permutations and still can't figure out a solution. Situation is
this :

I found great small javascript function that does permutations but
this is quite an unusual one.
Every single digit is assigned to 3 or 4 letters so for example
permutations of number 23
could look like this :

ad
ae
af
bd
be
bf
cd
ce
cf

javascipt code is very simple and it looks like too simple to
understand by me (Perl newbie)
because there is no direct loop, just calling a sub from inside this
same sub

I'm having troubles in understanding this code and then rewriting in
Perl so my question is this :
would it be easier to use some javascript module for Perl and paste
javascipt code inside perl script or rewriting this but with help of
permutation modules ?

Problem is that there are 3 or 4 letters per digit and user can input
whatever long number string.

- Telemach -

 

[Joost Diepenmaat]

I found great small javascript function that does permutations but
this is quite an unusual one.

I can't really make sense of your description. If the code is that
simple it's probably short enough to post it here.

javascipt code is very simple and it looks like too simple to
understand by me (Perl newbie)
because there is no direct loop, just calling a sub from inside this
same sub

Yes, recursion. If you've never seen it before it may take a little
getting used to, I guess. Perl can do this just fine:

# this is an extremely silly example

function rec {
my $i = shift;
if ($i <= 0) {
return 0;
}
else {
return $i + rec($i-1);
}
}

I'm having troubles in understanding this code and then rewriting in
Perl so my question is this :
would it be easier to use some javascript module for Perl and paste
javascipt code inside perl script or rewriting this but with help of
permutation modules ?

Using a javascript module for something that sounds as simple as this is
probably complicating the matter too much. You can translate most
javascript code fairly easily to perl.

Problem is that there are 3 or 4 letters per digit and user can input
whatever long number string.

I don't know what you're talking about.