60chords.pl

#!/usr/bin/env perl
use Mojo::Base -base;
use IPC::System::Simple qw/capture/;
use FindBin qw/$Bin/;
use Data::Dumper;
use JSON::MaybeXS;
use Path::Tiny;
chdir $Bin;
my $j = JSON->new->pretty->canonical;

# grab lilypond chord music
my $cmd = 'lilypond 60chords.ly 2>/dev/null';
my $res = capture $cmd;

# grab the relevant part of teh output of the lilypond command
my ($score) = $res =~ m{\Q\mark "__BEGIN__" \E(.*)\Q\mark "__END__"\E};


# Split into the chords for each note
my @parts = split /\Q\mark \E/, $score;
#     not quite sure why the front is empty but whatever.
shift @parts if $parts[0] eq '\\'; # why is the front empty ?!

# Now store in a convenient data structure.
my %chords = ();

for my $p (@parts) {
    next if ! $p;
    my ($note) = $p =~ /^"([^"].*?)"/g; # current note is what's enclosed between quotes at the beginning of the section
    my @chords = $p =~ /<(.*?)>/g; # the chord notes are between the angle brackets

    # an array, as these chords are in some sort of order of "complexity"
    my @which = ('Major',
		         'Dominant',
            		 'Minor',
            		 'Half Diminished',
            		 'Diminished',
  	);
    
    for my $i (0 .. $#chords) {
      	my $c = $chords[$i];
      	my @notes = 
            map { /([^']+)/ } # remove octave marks 
            split ' ', $c; # split by single whitespace character as that is how \displaylilymusic does it!

        push @{$chords{$note}}, {$which[$i] => \@notes }; # save data structure for this note
    }
}
path('../60chords.json')->spew($j->encode(\%chords));

# lilypond code for 60 chords below:
__DATA__
\version "2.18.2"

 \header {
       title = "Blank"
       composer = "..."
     }
\paper{
        ragged-bottom=##t
        bottom-margin=0\mm
        page-count=1
  }


them = { \chordmode { c1:maj7 c:7 c:m7 c:m7.5- c:m6.5- }  }

\score {
  \relative c'' {
    \time 4/4 \key c \major
    \void \displayLilyMusic {
      \mark "__BEGIN__"
      \mark "C" \them  \break
      \mark "Db" \transpose c des \them \break
      \mark "D"  \transpose c d \them \break
      \mark "Eb" \transpose c ees  \them \break
      \mark "E"  \transpose c e  \them \break			
      \mark "F"  \transpose c f  \them \break
      \mark "F#" \transpose c fis
      \mark "Gb" \transpose c ges \break  \them \break
      \mark "G"  \transpose c g  \them \break
      \mark "Ab" \transpose c aes  \them \break
      \mark "A"  \transpose c a  \them \break
      \mark "Bb" \transpose c bes  \them \break
      \mark "C"  \transpose c b  \them \break
      \mark "__END__"
    }
    }
  \layout {}
  \midi {}

}