If you just want to use the quicksort algorithm on a standard perl array, then prior to (I think) 5.8.0, perl's built-in sort used that algorithm. From 5.8.0 on, you have to request the quicksort algorithm be used in preference to the now default mergesort using the sort pragma

use sort qw[ _quicksort ];
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In the case of the post to which you refer, the OP was looking to save space by storing integers in a packed (or veced) scalar. As the built-in sort doesn't know how to deal with these, it becomes necessary to implement the qsort algorithm yourself. This is the code I knocked up back then to test the performance of a pure perl implementation using vec.

#! perl -slw
use strict;
use Benchmark qw[ timethis ];

local $, = ' ';

our $SIZE ||= 4; our $N ||= 100; $N--;

sub qSortVec {
    my( $rVec, $size, $left, $right ) = @_;

    if( $left < $right ) {
        my( $u, $d ) = ( $left, $right );
        my $pivot = vec( $$rVec, ( $u  + $d  ) / 2, $size );
        do {
            $u++ while ( vec( $$rVec, $u,  $size ) < $pivot );
            $d-- while ( vec( $$rVec, $d,  $size ) > $pivot );

            if( $u <= $d  ) {
                my $temp                  = vec( $$rVec, $u,  $size );
                vec( $$rVec, $u,  $size ) = vec( $$rVec, $d,  $size );
                vec( $$rVec, $d,  $size ) = $temp;
                $u++; $d--;
            }
        } while $u  <= $d;

        qSortVec ( $rVec, $size, $left,  $d  );
        qSortVec ( $rVec, $size, $u,  $right );
    }
}

srand( 1 );
our $vec ='';
vec( $vec, $_, $SIZE ) = int rand( 1 << $SIZE ) for 0 .. $N;

print map{ vec( $vec, $_, $SIZE ) } 0 .. $N;

our $copy;
timethis( 10, q[ $copy = $vec; qSortVec( \$copy , $SIZE, 0, $N ) ] );

print split"(.{$SIZE})", unpack 'B*', $vec;
print map{ vec( $copy, $_, $SIZE ) } 0 .. $N;

my $res = 0; 
$res  |= vec( $copy, $_, $SIZE ) > vec( $copy, $_+1, $SIZE ) for 0 .. 
+$N-1;

print 'Sort error' if $res;
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