G'day atcroft,

Here's a method using non-destructive transliteration. It requires 5.14 (see perl5140delta: Non-destructive substitution). The guts of the solution is:

sort { $a =~ y/ //dr cmp $b =~ y/ //dr } @data
[download]

I've tested with your OP data and tybalt's offering:

#!/usr/bin/env perl

use 5.014;
use warnings;

my @test_data = (
    [ atcroft => [
        'a',          #
        '  b',        #
        '  e',        #
        '    f',      #
        '      g',    #
        '  c',        #
        '    d',      #
        'h',          #
        '  i',        #
        '    j',      #
    ]],
    [ tybalt => [
        'j',          #
        '  i',        #
        '  h',        #
        '    g',      #
        '      f',    #
        '  e',        #
        '    d',      #
        'c',          #
        '  b',        #
        '    a',      #
    ]],
);

say_sorted(@$_) for @test_data;

sub say_sorted {
    my ($who, $data) = @_;
    say "Data from $who";
    say '-' x 20;
    say for @$data;
    say '-' x 20;
    say for sort { $a =~ y/ //dr cmp $b =~ y/ //dr } @$data;
    say '=' x 20;
}
[download]

Output:

Data from atcroft
--------------------
a
  b
  e
    f
      g
  c
    d
h
  i
    j
--------------------
a
  b
  c
    d
  e
    f
      g
h
  i
    j
====================
Data from tybalt
--------------------
j
  i
  h
    g
      f
  e
    d
c
  b
    a
--------------------
    a
  b
c
    d
  e
      f
    g
  h
  i
j
====================
[download]

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.