Search a concatenated Marked index file for include comments and adjust [[image.jpg]] tags to point to paths relative to included file

marked_gollum_pre.rb

#!/usr/bin/ruby
# Marked 2 preprocessor
# Search a concatenated Marked index file for include comments and adjust
# [[image.jpg]] tags to point to paths relative to included file
# Update: Converts [[tags]] to Markdown image tags using the generated paths

input = STDIN.read

includes = []

output = input.split(/\n/).map! { |line|
  if line =~ /<!-- include \[(.*?)\]/
    dir = File.dirname($1)
    includes.push(dir) unless includes.include?(dir)
  elsif line =~ /<!-- end include \[(.*?)\]/
    includes = includes.slice(0,includes.index(File.dirname($1)))
  end
  # line.gsub(/\[\[(.*?\|)?(.*?\.(?:png|svg|gif|jpg))\]\]/, "[[\\1#{includes[-1]}/\\2]]")
  line.gsub(/\[\[((.*?)\|)?(.*?\.(?:png|svg|gif|jpg))\]\]/, "![\\2](#{includes[-1]}/images/\\3)")
}.join("\n")

$stdout.print output