Treetop parser for Lua objects (limited)

gistfile1.rb

LUAOBJECT_GRAMMAR = %q{
grammar LuaObject

  rule luaobj
    space value space { def to_ruby; value.to_ruby; end }
  end

  rule value
    nil / float / number / string / table / boolean
  end

  rule nil
    'nil' { def to_ruby; nil; end }
  end

  rule table
    '{' space elementses:element* space '}' {
      def to_ruby(*args)
        temparray = elementses.elements.map { |x| x.to_ruby }
        return LuaObjectParser.splash_array(temparray)        
      end
    }
  end

  rule element
    space elementv space (',' &element / !element) {
      def to_ruby
        elementv.to_ruby
      end
    }
  end

  rule elementv
    key space '=' space value {
      def to_ruby
        hsh = { key.to_ruby => value.to_ruby }
        def hsh.intermediate_hash?
          true
        end
        hsh
      end
    }
    /
    value
  end

  rule key
    word
    /
    '[' space value space ']' {
      def to_ruby
        value.to_ruby
      end
    }
  end

  rule float
    [0-9]+ '.' [0-9]+ { def to_ruby; text_value.to_f; end }
  end

  rule number
    [0-9]+ {
      def to_ruby
        text_value.to_i
      end
    }
  end

  rule string
    '"' (!'"' . / '\"')* '"' {
      def to_ruby
        text_value[1..-2]
      end
    }
  end

  rule boolean
    ('true' / 'false') {
      def to_ruby
        text_value == 'true'
      end
    }
  end

  rule word
    [A-Za-z_]+ {
      def to_ruby
        text_value
      end
    }
  end

  rule space  
     [ \t\r\n]*  
  end    
end
}
File.open("luaobject.treetop","w") { |f| f << LUAOBJECT_GRAMMAR }

require 'treetop'
Treetop.load('luaobject')
class LuaObjectParser
  ##
  # Converts an array to a hash or array depending on the
  # contents. The parser returns an array mixed of PODs and Hashes. If
  # there are hashes, convert everything to a hash and insert
  # unindexed types with index as key.
  def self.splash_array(ary)
    if ary.find { |x| Hash === x and x.intermediate_hash? }
      idx = 1
      hsh = {}
      def hsh.intermediate_hash?; false; end
      ary.each { |x|
        if Hash === x and x.intermediate_hash?
          hsh[x.keys[0]] = x.values[0]
        else
          hsh[idx] = x
          idx += 1
        end
      }
      return hsh
    else
      return ary
    end
  end
end