Re: Comparing spaceships (cmp and <=> as options)

[moritz]

One problem is that if you write

\sub {<=>}

, the <=> doesn't receive any arguments (and doesn't even parse the way you want it to, because the parser expects a term, but finds an operator instead). So you have to write something like

sub { $_[0] <=> $_[1] }

instead. This code seems to work:

#!/usr/bin/perl
use strict;
use warnings;
use 5.010;
my $sort = 'hours'; # really comes from a switch

my %map = ( #     sorting map
    hours => [0, sub {$_[0] <=> $_[1]}],
    code  => [1, sub {$_[0] cmp $_[1]}],
    name  => [2, sub {$_[0] cmp $_[1]}],
);

# example data 
my @records = (
   [10, 'xyz232', 'secret project'],
   [ 5, 'foo123', 'world domination'],
   [ 7, 'bar666', 'have a beer'],
);

my $elem   = $map{$sort}[0];
my $sorter = $map{$sort}[1];

my @sorted = sort { $sorter->($a->[$elem], $b->[$elem]) } @records;

say join "\t", @$_ for @sorted;