Ruby Parser (Writing a Ruby to JS parser 5' demo)

hello.rb

class Pepe
  
  def name
    puts "Pepe"  
  end

end

message = "Hello "
puts(message)

Pepe.new.name

puts("!")

parser.rb

require 'ruby_parser'

def parse s
 case s[0]
 when :call then
   if s[1].nil? && s[2] == :puts
     "process.stdout.write(#{parse(s[3])})"    
   elsif s[2] == :new
     "new #{parse(s[1])}()"
   else
     "#{parse(s[1])}.#{s[2]}()"
   end
 when :lasgn then
   "#{s[1]} = #{parse(s[2])}"
 when :str then
   "\"#{s[1]}\""
 when :lvar then
   "#{s[1]}"
 when :class then
   "function #{s[1]} () {#{parse(s[3])}}"
 when :defn then
   "this.#{s[1]} = function(#{parse(s[2])}) {#{parse(s[3])}}"
 when :args then
   ""
 when :const
   "#{s[1]}"
 else
   ""
 end
end

script = ""

pt = RubyParser.for_current_ruby.parse File.read('./hello.rb')

puts pt.inspect 

if pt[0] == :block
    pt.each do |s|
      line = parse(s)
      script += "#{line};\n" unless line.nil? || line.empty?
    end
else
  script += parse(pt);
end

File.write('hello.js', script)