NAME
    Sort::SubList - Sort only certain elements in a list, while maintaining
    the order of the rest

VERSION
    This document describes version 0.001 of Sort::SubList (from Perl
    distribution Sort-SubList), released on 2019-12-14.

SYNOPSIS
     use Sort::SubList qw(sort_sublist);

     my @sorted = sort_sublist
         sub { length($_[0]) <=> length($_[1]) },  # comparison routine
         sub { /\D/ },                             # element selection routine
         "quux", 12, 1, "us", 400, 3, "a", "foo";

     # => ("a", 12, 1, "us", 400, 3, "foo", "quux")

DESCRIPTION
    This module provides "sort_sublist" routine to sort only certain
    elements in a list, while keeping the order of the rest of the elements
    intact (in the original position). So basically what this routine does
    is to grep the elements to be sorted, record their positions, sort these
    elements, and put them back to the recorded positions.

FUNCTIONS
  sort_sublist
    Usage:

     my @sorted = sort_sublist $comparison_sub, $filter_sub, @list;

FAQ
  How about adding prototype to "sort_sublist" so it's more convenient to use like the builtin "sort"?
    The builtin "sort"'s behavior is hard to emulate with subroutine
    prototypes. For more discussion:
    <https://www.perlmonks.org/index.pl/www.mrtg.org?node_id=1207981>. For
    simplicity, I do away with prototypes altogether.

  How to use $a and $b in comparison sub, just like when we use builtin "sort"?
    Something like this will do:

        sub {
            no strict 'refs';

            my $caller = caller();
            my $a = @_ ? $_[0] : ${"$caller\::a"};
            my $b = @_ ? $_[1] : ${"$caller\::b"};

            # compare $a and $b ...
        }

    Or, you can just use $_[0] (instead of $a) and $_[1] (instead of $b)
    like the example in Synopsis shows. Again, this is where the specialness
    of the sort subroutine is not easy or straightforward to emulate.

HOMEPAGE
    Please visit the project's homepage at
    <https://metacpan.org/release/Sort-SubList>.

SOURCE
    Source repository is at
    <https://github.com/perlancar/perl-Sort-SubList>.

BUGS
    Please report any bugs or feature requests on the bugtracker website
    <https://rt.cpan.org/Public/Dist/Display.html?Name=Sort-SubList>

    When submitting a bug or request, please include a test-file or a patch
    to an existing test-file that illustrates the bug or desired feature.

SEE ALSO
AUTHOR
    perlancar <perlancar@cpan.org>

COPYRIGHT AND LICENSE
    This software is copyright (c) 2019 by perlancar@cpan.org.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.