Here's one way:

#!/usr/bin/perl

use strict;
use warnings;

my $char;
BEGIN { $char = 1; }

use charnames ":alias" => { map { $_ => $char++ } (
  'first character',
  'second character',
  'third character'
)};

printf "First: %X; third: %X\n",
  ord("\N{first character}"),
  ord("\N{third character}");
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Note: Using 0 as a value for $char didn't work.

Hope this helps!

update: fixed typo