And here's a Perl 5.16 implementation of quicksort...

use v5.16;
my @sorted = (sub {
    return @_ unless @_ > 1;
    my $pivot = splice(@_, int(@_/2), 1);
    my (@small, @big);
    push @{ $_ < $pivot ? \@small : \@big }, $_ for @_;
    return (__SUB__->(@small), $pivot, __SUB__->(@big))
})->(@unsorted);

[download]

Can be made a little neater using List::MoreUtils...

use v5.16;
use List::MoreUtils 'part';
my @sorted = (sub {
    return @_ unless @_ > 1;
    my $pivot = splice(@_, int(@_/2), 1);
    my ($small, $big) = part { $_ > $pivot } @_;
    return (__SUB__->(@$small), $pivot, __SUB__->(@$big))
})->(@unsorted);

[download]

In older Perls, without __SUB__ you can't recursively call a truly anonymous sub, so you need to have some kind of way of referring to the sub, such as assigning it to a lexical variable...

my @sorted = do { my $SUB; $SUB = sub {
    return @_ unless @_ > 1;
    my $pivot = splice(@_, int(@_/2), 1);
    my (@small, @big);
    push @{ $_ < $pivot ? \@small : \@big }, $_ for @_;
    return ($SUB->(@small), $pivot, $SUB->(@big))
}}->(@array);

[download]
perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

In reply to Re^2: Numeric sorting WITHOUT <=> by tobyink
in thread Numeric sorting WITHOUT <=> by Anonymous Monk

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