Hoof: ruby script to convert ABC tunes from thesession.org to lilypond files

Snip

ruby script to convert ABC tunes from thesession.org to lilypond files

#!/usr/bin/env ruby

require 'optparse'
require 'open-uri'
require 'rexml/document'
require 'iconv'

def sanitize( string )
  #replace non alpha-numerics with _
  string = string.gsub(/[^A-z0-9_]/,'_')
  return string.downcase
end

def error( string )
  puts "**** ERROR ****"
  puts string
  exit
end

option = {}
OptionParser.new do |opts|
  opts.banner = "Usage: sessionconvert [options] [thesession.org_URL]"
  
  opts.on("-b", "--banjo", "add banjo tabulature") do |v|
    option[:banjo] = v
  end
  
  opts.on("-l", "--lilypond", "compile with lilypond") do |v|
    option[:lilypond] = v
  end
  
end.parse!

url =  ARGV[0]
# was a url supplied?
unless url
  error "you must supply a thesession.org url"
end

begin
  text = open(url).read
rescue
  error "Failed to read #{url}"
end

begin
  #watch out for sneaky 
  ic = Iconv.new('UTF-8//IGNORE', 'UTF-8')
  valid_string = ic.iconv(text)
  doc = REXML::Document.new valid_string
rescue
  error "Failed to parse #{url}"
end

root = doc.root
p = root.elements["body/div[@id='abc']/div[@class='box']/p"].to_s
abc = p.gsub(/<.*>/,'')

#get the title
m = /T: (?<title>.*)/.match( abc )
title = m['title']
#get the key
m = /K: (?<key>.*)/.match( abc )
key = m['key']

#sanitize the title, we will use this a bunch
sanitized_title = sanitize(title)
#what will the filenames be?
filename_abc = sanitized_title+".abc"

f = open(filename_abc,'w')
f.write(abc)
f.close

begin
  `abc2ly #{filename_abc}`
rescue
  error "abc2ly is not installed"
end

#what will the lilypond file be?
filename_ly = sanitized_title+".ly"

if option[:banjo]
  #what is the key we are transposing from
  t_key = key[0].downcase
  banjer_bit = "\\transpose  #{t_key} g,
    \\context TabStaff = \"banjer\"{
    \\set TabStaff.stringTunings = #banjo-open-g-tuning
    \\set Staff.instrumentName = #\"Banjo\"
    \\context TabVoice = \"banjer\" { \\tabFullNotation \\stemDown \\voicedefault }
  }"

text = File::read(filename_ly)
  #substitute the banjer stuff
  text = text.gsub(/<<.*>>/m, "<<\n #{banjer_bit}\n\t>>")
  #make a new lilypond file
  filename_ly = sanitized_title+"-banjo.ly"
  #write the new text to file
  f = open(filename_ly,'w')
  f.write(text)
  f.close
  
end

#did the user request compiling 
begin
  `lilypond #{filename_ly}` if option[:lilypond]
rescue
  error "lilypond is not installed"
end