class Treetop::Compiler::GrammarCompiler

def compile(source_path, target_path = source_path.gsub(/\.(treetop|tt)\Z/, '.rb'))
  File.open(target_path, 'w') do |target_file|
    target_file.write(ruby_source(source_path))
  end
end

def ruby_source(source_path)
  File.open(source_path) do |source_file|
    parser = MetagrammarParser.new
    result = parser.parse(source_file.read)
    unless result
      raise RuntimeError.new(parser.failure_reason)
    end
    result.compile
  end
end