toy lispy parser

gistfile1.rb

#!/usr/bin/env ruby

require 'parslet'

class Lispy < Parslet::Parser
  rule(:integer)    { match('[0-9]').repeat(1) }
  rule(:literal)    { integer }
  rule(:identifier) { match('[^0-9\'"]') >> match('.').repeat(0)}
  rule(:atom)       { identifier | literal }
  rule(:spaces)     { match('\s').repeat(1) }
  rule(:spaces?)    { spaces.maybe }
  rule(:item)       { spaces? >> (list | atom) >> spaces? }
  rule(:list)       { str('(') >> item.repeat(0) >> str(')') }
  root(:list)
end

p Lispy.new.parse("(112)")
p Lispy.new.parse("((112))")