tp2md.rb

#!/usr/bin/env ruby
# Usage: tp2md.rb filename.taskpaper > output.md
# Updated 2025-03-19
# - Fix block quote indentation
# - use GFM-style - [ ] markers
# - convert @tags to #tags
# - <self-link> bare urls
# - Accept input piped on STDIN

if $stdin.stat.size.positive?
  input = $stdin.read
  title = "TODO"
else
  input = File.read(ARGV[0])
  title = File.basename(ARGV[0],'.taskpaper').capitalize
end

output = "# #{title} #\n\n"
prevlevel = 0
begin
    input.each_line do |line|
      if line =~ /^(\t*)(.*?):(?:\s*)$/
        tabs = $1
        project = $2
        if tabs.nil?
          output += "\n## #{project} ##\n\n"
          prevlevel = 0
        else
          output += "#{tabs.gsub(/^\t/,'')}* **#{project}**\n"
          prevlevel = tabs.length
        end
      elsif line =~ /^(\t+)?\- (.*)$/
        task = $2
        tabs = $1.nil? ? '' : $1
        marker = task =~ /@done/ ? '- [x]' : '- [ ]'
        if tabs.length - prevlevel > 1
          tabs = "\t"
          prevlevel.times {|i| tabs += "\t"}
        end
        tabs = '' if prevlevel == 0 && tabs.length > 1
        output += "#{tabs.gsub(/^\t/,'')}#{marker} #{task.strip}\n"
        prevlevel = tabs.length
      else
        next if line =~ /^\s*$/
        tabs = ""
        prevlevel.times {|i| tabs += "\t"}
        output += "#{tabs}> #{line.strip}\n\n"
      end
    end
rescue => err
    puts "Exception: #{err}"
    err
end
output.gsub!(/(?mi)(?<!\]\(|\]: )\b((?:[\w-]+?:\/\/)(?:\S+?))(?=[\s\n)]|$)/, '<\1>')
puts output.gsub(/@(?=\S)/, '#')

Updated for modern systems, see comments at top for changes