File Coverage

blib/lib/Sort/SubList.pm

Criterion	Covered	Total	%
statement	26	26	100.0
branch	4	6	66.6
condition			n/a
subroutine	5	5	100.0
pod	1	1	100.0
total	36	38	94.7

package Sort::SubList;

our $AUTHORITY = 'cpan:PERLANCAR'; # AUTHORITY
our $DATE = '2019-12-14'; # DATE
our $DIST = 'Sort-SubList'; # DIST
our $VERSION = '0.001'; # VERSION

use 5.010001;
use strict 'subs', 'vars';
use warnings;

use Exporter qw(import);
our @EXPORT_OK = qw(sort_sublist);

sub sort_sublist {
    my $cmp_sub    = shift
        or die "Please supply comparison routine (first arg)";
    my $select_sub = shift
        or die "Please supply elemnet selection routine (second arg)";
    my @list = @_;

    my @pos_selected;
    my @selected;

  ELEM:
    for my $i (0..$#_) {
        { local $_ = $list[$i]; next ELEM unless $select_sub->($_) }
        push @selected, $list[$i];
        push @pos_selected, $i;
    }
    @selected = sort { $cmp_sub->($a, $b) } @selected;

    for (0..$#pos_selected) {
        $list[ $pos_selected[$_] ] = $selected[$_];
    }

    @list;
}

1;

# ABSTRACT: Sort only certain elements in a list, while maintaining the order of the rest

__END__