module PLang
  module Ast
    class PStatement
      def initialize(expression)
        @expression = expression
      end

      def to_sexp
        @expression.to_sexp
      end
    end

    class PUnOp
      attr_reader :op
      attr_reader :right
      def initialize(op, right)
        @op = op
        @right = right
      end

      def to_sexp
        [@op, @right.to_sexp]
      end
    end

    class PBinOp
      attr_reader :op
      attr_reader :left
      attr_reader :right

      def initialize(op, left, right)
        @op = op.to_sym
        @left = left
        @right = right
      end

      def to_sexp
        [@op, @left.to_sexp, @right.to_sexp]
      end
    end

    class PLiteral
      attr_reader :type
      attr_reader :value

      def initialize(type, value)
        @type = type.to_sym
        @value = value
      end

      def to_sexp
        [:literal, @type, @value]
      end
    end

    class PId
      attr_reader :name

      def initialize(name)
        @name = name.to_sym
      end

      def to_sexp
        [:id, @name]
      end
    end

    class PObject
      attr_reader :name

      def initialize(name, params)
        @name = name.to_sym
        @params = params
      end

      def to_sexp
        [:object, @name, @params.collect(&:to_sexp)]
      end
    end

    class PCall
      attr_reader :cid

      def initialize(cid, params)
        @cid = cid
        @params = params
      end

      def to_sexp
        @cid = @cid.to_sexp
        if @cid == [:id, :if]
          @params = @params.collect(&:to_sexp)
          if @params.size == 3
            [:if, @params[0], @params[1], @params[2]]
          else
            raise "'if' error"
          end
        elsif @cid == [:id, :begin]
          [:begin, @params.collect(&:to_sexp)]
        else
          [:call, @cid, @params.collect(&:to_sexp)]
        end
      end
    end

    class PLet
      attr_reader :var
      attr_reader :val

      def initialize(var, val)
        @var = var
        @val = val
      end

      def to_sexp
        [:let, @var.to_sexp, @val.to_sexp]
      end
    end

    class PLambda
      attr_reader :params
      attr_reader :expr
      attr_reader :where
      attr_accessor :next_lambda

      def initialize(params, expr, where)
        @params = params
        @expr = expr
        @where = where
        @next_lambda = nil
      end

      def to_sexp
        [:lambda, @params.collect(&:to_sexp), @expr.to_sexp, @where.collect(&:to_sexp), @next_lambda]
      end
    end

    class PObjectCall
      attr_reader :obj
      attr_reader :msg

      def initialize(obj, msg)
        @obj = obj
        @msg = msg
      end

      def to_sexp
        [:object_call, @obj.to_sexp, @msg.to_sexp]
      end
    end

    class PObjectLet
      attr_reader :obj
      attr_reader :id
      attr_reader :value

      def initialize(obj, id, value)
        @obj = obj
        @id = id
        @value = value
      end

      def to_sexp
        [:object_let, @obj.to_sexp, @id.to_sexp, @value.to_sexp]
      end
    end
  end
end