> it generates these kinds of patterns very efficiently

I tried Algorithm::Combinatorics for a similar task. Both of these examples generate an array of strings n characters in length of all combinations of letters (e.g. 4 = 'aaaa'..'zzzz'). Am I doing something stupid with the module, or perl?

Perl string iteration:
real 0m0.129s

time perl -wle '
$n = shift; die "need a number" unless $n and $n =~ /^\d+$/; 
$a = "a" x $n; $c = 0; $e = 26**$n; 
while () { push @x, $a; $a++ and $c++; last if $c == $e } 
print scalar @x' 4
[download]

Using Algorithm::Combinatorics:
real 0m0.858s

time perl -MAlgorithm::Combinatorics=:all -wle '
$n = shift; die "need a number" unless $n and $n =~ /^\d+$/; 
@_ = ("a".."z"); $i = variations_with_repetition(\@_,$n); 
while ($c =  $i->next){
for  (@$c) { $x .= $_ } 
push @x, $x; undef $x } 
print scalar @x' 4
[download]

Be careful with the parameter because this can make a very big array.
4 is only ~2MB but 5 is 70MB and the 6 character array is around 2000MB.

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