From: Adam Shelly <adam.shelly@...>
Date: 2006-05-18T01:50:10+09:00
Subject: Re: [QUIZ] Tab Player (#79)

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Here's my short solution.  It just assumes any set of 6 equal-length lines
starting with ('A'..'G') are a tab, and ignores the rest of the file.
It passes everything it finds on the tab lines to the guitar, since I was
hoping to improve guitar.rb to handle hammers and slides and such..
Unfortunately, real life just takes too much time...

---begin player.rb  ------
require 'guitar.rb'

tuningMap =3D {
  'EADGBE' =3D> Guitar::EADGBE,
  'DADGBE' =3D> Guitar::DADGBE,
  'DGCFAD'=3D> Guitar::DGCFAD
}


puts "usage: Player.rb tabfile" or exit if ARGV.size < 1
lines,lastlength=3D[],nil
until ARGF.eof do
  lines << ARGF.gets.chomp.split('');
  #read until we find 6 lines of same length
  if lastlength and lastlength !=3D lines[-1].length
    #throw away nonmatching lines
    lines.shift while lines.size > 1
  end
  lastlength =3D lines[-1].length
  if lines.size =3D=3D 6
    sig =3D lines.inject([]){|a,l| a <<l.shift}
    #make sure it has a key signature
    if !sig.find{|e| !e or !(("A".."G").include?(e.upcase))}
      #create a guitar in the key of the first tab found.
      g ||=3D Guitar.new(Guitar::NYLON_ACOUSTIC,
                        tuningMap[sig.reverse.join.upcase])
      until (lines[0].empty?)
        note =3D lines.inject([]){|a,l| a << l.shift}
        if (note[0]!=3D'|')
          p note.join if $DEBUG
          g.play(note.join)
        end
      end
    end
    lines.clear
  end
end
File.open("tab.mid","wb") {|f| f.write(g.dump)}


----
-Adam


On 5/17/06, Ross Bamford <rossrt@roscopeco.co.uk> wrote:
>
> This is the 'proof of concept' solution I wrote for this quiz. It just
> uses a regexp approach to extract whatever tab it can find from the
> input, and it has the limitations mentioned in the quiz (9 frets, etc).
>
> #!/usr/local/bin/ruby
> #
> # This is a very simple solution to this quiz, using
> # the simple software guitar supplied. Run e.g:
> #
> #   ./playtab.rb sometab.tab | timidity -Os -
> #
> # Using the correct -O (s is ALSA - see --help for more).
> # Alternatively, file the output and load it in your
> # midi player.
> #
> require 'guitar'
>
> tabre =3D /(([eADGBE]\|?
>          [\-0-9~xhpbrBend\(\)\[\]\{\}=3D*|#]+
>          [.\r\n]*){6})/x
> tabs =3D []
>
> ARGF.read.scan(tabre) {
>   tab =3D $1.split
>   tabs << tab if tab.all? { |line| line.length =3D=3D tab[0].length }
> }
>
> axe =3D Guitar.new(Guitar::CLEAN_ELECTRIC)
> tabs.inject([[]]) do |bars,t|
>   (t[0].length - 2).times do |i|
>     notes =3D t.inject("") { |s,line| s << line[i+2] }.reverse
>     if notes =3D~ /[|*]{6}/
>       bars << []
>     else
>       bars.last << notes
>     end
>   end
>   bars
> end.reject { |a| a.empty? }.each do |bar|
>   bar.each do |notes|
>     axe.play(notes)
>   end
> end
>
> $stdout.write(axe.dump)
>
> --
> Ross Bamford - rosco@roscopeco.REMOVE.co.uk
>
>
>

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