require 'melbourne/ast'

module Melbourne

  # Exception that is raised whenever Melbourne encounters anything it cannot parse.
  # When this exception is raised, the parsed code is most likely not syntactically valid.
  #
  class ParserError < Exception; end

  class Parser
    def process_parse_error(message, column, line, source)
      @exc = SyntaxError.from message, column, line, source, @name
    end

    def process_dangling_node
      raise ParserError.new('Processing called but node was NULL')
      # TODO: output info about the current AST node
    end

    # This method is analogous to #method_missing. It is called
    # if there is no processing method defined for a node.
    def process_missing_node(line, node_name, node_type)
      raise ParserError.new("Unhandled node #{node_name} (#{node_type})")
    end

    # Processing methods

    def process_alias(line, to, from)
      AST::Alias.new line, to, from
    end

    def process_and(line, left, right)
      AST::And.new line, left, right
    end

    def process_args(line, args, defaults, splat)
      AST::FormalArguments.new line, args, defaults, splat
    end

    def process_argscat(line, array, rest)
      AST::ConcatArgs.new line, array, rest
    end

    def process_argspush(line, arguments, value)
      AST::PushArgs.new line, arguments, value
    end

    def process_array(line, array)
      AST::ArrayLiteral.new line, array
    end

    def process_attrasgn(line, receiver, name, arguments)
      if name == :[]=
        AST::ElementAssignment.new line, receiver, arguments
      else
        AST::AttributeAssignment.new line, receiver, name, arguments
      end
    end

    def process_back_ref(line, ref)
      AST::BackRef.new line, ref
    end

    def process_begin(line, body)
      AST::Begin.new line, body
    end

    def process_block(line, array)
      AST::Block.new line, array
    end

    def process_block_arg(line, name)
      AST::BlockArgument.new line, name
    end

    def process_block_pass(line, method_send, body)
      node = AST::BlockPass.new line, body
      if method_send
        method_send.block = node
        method_send
      else
        node
      end
    end

    def process_break(line, value)
      AST::Break.new line, value
    end

    def process_call(line, receiver, name, arguments)
      if arguments
        AST::SendWithArguments.new line, receiver, name, arguments
      else
        AST::Send.new line, receiver, name
      end
    end

    def process_case(line, receiver, whens, else_body)
      if receiver
        AST::ReceiverCase.new line, receiver, whens, else_body
      else
        AST::Case.new line, whens, else_body
      end
    end

    def process_cdecl(line, expr, value)
      AST::ConstSet.new line, expr, value
    end

    def process_class(line, name, superclass, body)
      AST::Class.new line, name, superclass, body
    end

    def process_colon2(line, outer, name)
      if outer
        AST::ConstAccess.new line, outer, name
      else
        AST::ConstFind.new line, name
      end
    end

    def process_colon3(line, name)
      AST::ConstAtTop.new line, name
    end

    def process_const(line, name)
      AST::ConstFind.new line, name
    end

    def process_cvar(line, name)
      AST::ClassVariableAccess.new line, name
    end

    def process_cvasgn(line, name, value)
      AST::ClassVariableAssignment.new line, name, value
    end

    def process_cvdecl(line, name, value)
      AST::ClassVariableAssignment.new line, name, value
    end

    def process_data(line, data)
      AST::EndData.new line, data
    end

    def process_defined(line, expr)
      AST::Defined.new line, expr
    end

    def process_defn(line, name, body)
      AST::Define.new line, name, body
    end

    def process_defs(line, receiver, name, body)
      AST::DefineSingleton.new line, receiver, name, body
    end

    def process_dot2(line, start, finish)
      AST::Range.new line, start, finish
    end

    def process_dot3(line, start, finish)
      AST::RangeExclude.new line, start, finish
    end

    def process_dregx(line, str, array, flags)
      AST::DynamicRegex.new line, str, array, flags
    end

    def process_dregx_once(line, str, array, flags)
      AST::DynamicOnceRegex.new line, str, array, flags
    end

    def process_dstr(line, str, array)
      AST::DynamicString.new line, str, array
    end

    def process_dsym(line, str, array)
      AST::DynamicSymbol.new line, str, array
    end

    def process_dxstr(line, str, array)
      AST::DynamicExecuteString.new line, str, array
    end

    def process_ensure(line, body, ensr)
      AST::Ensure.new line, body, ensr
    end

    def process_evstr(line, value)
      if value
        AST::ToString.new line, value
      else
        AST::StringLiteral.new line, ""
      end
    end

    def process_false(line)
      AST::False.new line
    end

    def process_fcall(line, name, arguments)
      receiver = AST::Self.new line

      if arguments
        AST::SendWithArguments.new line, receiver, name, arguments, true
      else
        AST::Send.new line, receiver, name, true
      end
    end

    def process_file(line)
      AST::File.new line
    end

    def process_fixnum(line, value)
      AST::FixnumLiteral.new line, value
    end

    def process_flip2(line, start, finish)
      AST::Flip2.new line, start, finish
    end

    def process_flip3(line, start, finish)
      AST::Flip3.new line, start, finish
    end

    def process_float(line, str)
      AST::Float.new line, str
    end

    def process_for(line, iter, arguments, body)
      method_send = AST::Send.new line, iter, :each
      method_send.block = AST::For.new line, arguments, body
      method_send
    end

    def process_gasgn(line, name, expr)
      AST::GlobalVariableAssignment.new line, name, expr
    end

    def process_gvar(line, name)
      AST::GlobalVariableAccess.new line, name
    end

    def process_hash(line, array)
      AST::HashLiteral.new line, array
    end

    def process_iasgn(line, name, value)
      AST::InstanceVariableAssignment.new line, name, value
    end

    def process_if(line, cond, body, else_body)
      AST::If.new line, cond, body, else_body
    end

    def process_iter(line, method_send, arguments, body)
      method_send.block = AST::Iter.new line, arguments, body
      method_send
    end

    def process_ivar(line, name)
      AST::InstanceVariableAccess.new line, name
    end

    def process_lasgn(line, name, value)
      AST::LocalVariableAssignment.new line, name, value
    end

    def process_lit(line, sym)
      AST::SymbolLiteral.new line, sym
    end

    def process_lvar(line, name)
      AST::LocalVariableAccess.new line, name
    end

    def process_masgn(line, left, right, splat)
      AST::MAsgn.new line, left, right, splat
    end

    def process_match(line, pattern, flags)
      AST::Match.new line, pattern, flags
    end

    def process_match2(line, pattern, value)
      AST::Match2.new line, pattern, value
    end

    def process_match3(line, pattern, value)
      AST::Match3.new line, pattern, value
    end

    def process_module(line, name, body)
      AST::Module.new line, name, body
    end

    def process_negate(line, value)
      AST::Negate.new line, value
    end

    def process_next(line, value)
      AST::Next.new line, value
    end

    def process_nil(line)
      AST::Nil.new line
    end

    def process_not(line, value)
      AST::Not.new line, value
    end

    def process_nth_ref(line, ref)
      AST::NthRef.new line, ref
    end

    def process_number(line, base, str)
      value = str.to_i base
      case value
      when Fixnum
        AST::FixnumLiteral.new line, value
      when Bignum
        AST::NumberLiteral.new line, value
      end
    end

    def process_op_asgn1(line, receiver, index, op, value)
      AST::OpAssign1.new line, receiver, index, op, value
    end

    def process_op_asgn2(line, receiver, name, op, value)
      AST::OpAssign2.new line, receiver, name, op, value
    end

    def process_op_asgn_and(line, var, value)
      AST::OpAssignAnd.new line, var, value
    end

    def process_op_asgn_or(line, var, value)
      AST::OpAssignOr.new line, var, value
    end

    def process_or(line, left, right)
      AST::Or.new line, left, right
    end

    def process_postexe(line)
      AST::Send.new line, AST::Self.new(line), :at_exit, true
    end

    def process_redo(line)
      AST::Redo.new line
    end

    def process_regex(line, str, flags)
      AST::RegexLiteral.new line, str, flags
    end

    def process_resbody(line, conditions, body, nxt)
      AST::RescueCondition.new line, conditions, body, nxt
    end

    def process_rescue(line, body, rescue_body, else_body)
      AST::Rescue.new line, body, rescue_body, else_body
    end

    def process_retry(line)
      AST::Retry.new line
    end

    def process_return(line, value)
      AST::Return.new line, value
    end

    def process_sclass(line, receiver, body)
      AST::SClass.new line, receiver, body
    end

    def process_scope(line, body)
      if body.kind_of? AST::Block
        body
      elsif body
        AST::Block.new line, [body]
      end
    end

    def process_self(line)
      AST::Self.new line
    end

    def process_splat(line, expr)
      AST::SplatValue.new line, expr
    end

    def process_str(line, str)
      AST::StringLiteral.new line, str
    end

    def process_super(line, args)
      AST::Super.new line, args
    end

    def process_svalue(line, expr)
      AST::SValue.new line, expr
    end

    def process_to_ary(line, expr)
      AST::ToArray.new line, expr
    end

    def process_true(line)
      AST::True.new line
    end

    def process_undef(line, sym)
      AST::Undef.new line, sym
    end

    def process_until(line, cond, body, check_first)
      AST::Until.new line, cond, body, check_first
    end

    def process_vcall(line, name)
      receiver = AST::Self.new line

      AST::Send.new line, receiver, name, true
    end

    def process_valias(line, to, from)
      AST::VAlias.new line, to, from
    end

    def process_when(line, conditions, body)
      AST::When.new line, conditions, body
    end

    def process_while(line, cond, body, check_first)
      AST::While.new line, cond, body, check_first
    end

    def process_xstr(line, str)
      AST::ExecuteString.new line, str
    end

    def process_yield(line, arguments, unwrap)
      AST::Yield.new line, arguments, unwrap
    end

    def process_zarray(line)
      AST::EmptyArray.new line
    end

    def process_zsuper(line)
      AST::ZSuper.new line
    end
  end

end