[oak perl] GNU and recursion

[Belden Lyman]

George Woolley wrote:
> My understanding from the GNU project site is that:
>       GNU is a recursive acronym for "GNU's Not Unix'" 
> 
> So I'm thinking: 
> GNU(0)   equals   GNU
> GNU(1)   equals   GNU's Not Unix
> 
> My first question: what do
> GNU(2), GNU(3), etc. equal?
> 
> And my second question:
> what would the Perl function look like 
> for generating the values of GNU(0), GNU(1), GNU(2), etc.?
> 
> 

An iterative solution:

#!/usr/bin/perl

use strict;
use warnings;

print gnu_i('GNU',2),"\n";

sub gnu_i {
   my ($str, $itr) = @_;
   for ( 0..$itr ) {
     $str =~ s/GNU/(GNU's Not Unix)/;
   }
   $str;
}
__END__



A recursive solution:

#!/usr/bin/perl

use strict;
use warnings;

print gnu_r('GNU',2), "\n";

sub gnu_r {
   my ( $str, $itr ) = @_;
   if ( $itr < 0 ) {
     return $str;
   }
   $str =~ s/GNU/(GNU's Not Unix)/;
   return gnu_r( $str, --$itr );
}
__END__


Belden