require 'ripper'
require 'pp'

module Kernel
  def rpp(ast)
    pp ast
    parse_r(ast)
  end

  def parse_r(ast, depth = 0, space: ' ')
    if ast.first.instance_of?(Array)
      parse_r(ast.first, depth, space: space)
      return
    end
    id = ast.first

    if %i(@int @float @rational @imaginary).include?(id)
      puts ast[1..-2]
      return
    else
      puts "#{id.inspect}"
    end

    child_count = ast[1..-1].count {|e| e.instance_of?(Array) }

    if child_count.zero?
      print "#{space}#{ast[1..-1].map(&:inspect).join(', ')}"
    else
      ast[1..-1].each do |elem|
        if ast[-1] == elem
          print "#{space}└─── "
        else
          print "#{space}├─── "
        end

        if elem.instance_of?(Array)
          if ast[-1] == elem
            parse_r(elem, depth+1, space: space + ' ' * 10)
          else
            parse_r(elem, depth+1, space: space + '│' + ' ' * 8)
          end
        else
          puts "#{elem.inspect}"
        end
      end
    end
  end
end

rpp Ripper.sexp("3 + 4 + 313")

__END__
[:program,
 [[:binary,
   [:binary, [:@int, "3", [1, 0]], :+, [:@int, "4", [1, 4]]],
   :+,
   [:@int, "313", [1, 8]]]]]
:program
 └─── :binary
           ├─── :binary
           │        ├─── 3
           │        ├─── :+
           │        └─── 4
           ├─── :+
           └─── 313