Converts Markdown lazy link asterisks into standard footer link reference numbers.

lazy-to-footer.pl

#!/usr/bin/perl

# Lazy Link Markdown Converter
# A less-elegant Perl port of Brett Terpstra's Ruby script:
# http://brettterpstra.com/2013/10/19/lazy-markdown-reference-links/
 
# Converts Markdown lazy link asterisks into standard footer link
# reference numbers.

# Serving Suggestions: Pipe text into lazylink_converter.pl
# from the command line or install as a BBEdit Text Filter.

# Can also be used as a preprocessor for Marked.
# http://marked2app.com/
 
# 2014 Josh Centers. http://joshcenters.com/

use strict;
use warnings;
use diagnostics;

my $text;                          # Our hero, the $text variable. 
local $/;                          # Grab all the text.
$text = <>;                        # Assign STDIN to our hero.

my $url_count = 1;
my $link_count = 1;

# This foreach loop finds each link, formatted like so: [TKTK][*],
# replaces the asterisk with the variable $link_count, then increments
# $link_count by one.

foreach ($text =~ m/(\[.+?\]\[)\*(\])/g) {
	$text =~ s/(\[.+?\]\[)\*(\])/$1$link_count$2/;
	$link_count++;
}

# This foreach loop finds each link, formatted like so:
# [*]: http://www.TKTK.com, replaces the asterisk with the
# variable $url_count, then increments $url_count by one.

foreach ($text =~ m/(\[)\*(\]\:)/g) {
	$text =~ s/(\[)\*(]:)/$1$url_count$2/;
	$url_count++;
}

print $text;