Chordproko

Chordproko is a parser for ruby. It converts chordpro format to a readable text format.

Add this line to your application's Gemfile:

gem 'chordproko'

And then execute:

$ bundle

Or install it yourself as:

$ gem install chordproko

Suppose you have a song sheet written in ChordPro format:

sheet = "Th[C]is is a sam[G]ple lyr[Em]ic with ch[D]ord"
readable_sheet = Chordproko.text(sheet)

Or load from file

file = File.new("file_location")
readable_sheet = Chordproko.text(file.read)

You can transpose a song by adding transpose option.

readable_sheet = Chordproko.text(file.read, transpose: 2)

Negative value means transpose down, otherwise, transpose up.

Create your own algorithm using the result of Chordproko Parser. It uses parslet so you have to learn parslet first. You can check the source code for rules.

parsed = Chordproko::Parser.new.parse(file.read)

Then, create your own Transform class.

class MyPlainSong < Chordproko::PlainSong
  def initialize transformed, options={}
    super(transformed, options)
  end
  def chord_group_format str
    "<span>#{str}</span>"
  end
  def lyric_line_format str
    "<div>#{str}</div>"
  end
end

Set the Chordproko formatter class. This will globally set our formatter.

Chordproko.set_formatter_class("MyPlainSong")

Then use the Chordproko .text method

Aside from those two methods, you can override these to modify your song sheet.

def chord_line_format str
  ...
end
def comment_format str
  ...
end
def directive_format str
  ...
end
def lyric_format str
  ...
end

• Improve specs
• Improve documentations
• Improve source (so many unnecessary lines. It works, so it's fine for now.)
• Support b flat sign
• Implement PlainSong methods with block (Might help a lot in customizing contents.)
• Add settings and customization
• Learns sheet key.

I'm certain that you have reached this section haha. This is my first gem, I still have a lot to learn. You can report errors, suggest features and create pull requests here, https://github.com/neume/chordproko.

The gem is available as open source under the terms of the MIT License.