예제 #1
0
파일: core.py 프로젝트: xxyzzzq/quex
    def prepare_state(self, OldState, StateIndex, OnBeforeEntry):
        """REQUIRES: 'self.init_state_forward_f', 'self.engine_type', 'self.__from_db'.
        """
        state = AnalyzerState.from_State(OldState, StateIndex, self.engine_type)

        cmd_list = []
        if self.engine_type.is_BACKWARD_PRE_CONTEXT():
            cmd_list.extend(
                 Op.PreContextOK(cmd.acceptance_id()) 
                 for cmd in OldState.single_entry.get_iterable(SeAccept)
            )

        if state.transition_map is None and False: 
            # NOTE: We need a way to disable this exception for PathWalkerState-s(!)
            #       It's safe, not to allow it, in general.
            #------------------------------------------------------------------------
            # If the state has no further transitions then the input character does 
            # not have to be read. This is so, since without a transition map, the 
            # state immediately drops out. The drop out transits to a terminal. 
            # Then, the next action will happen from the init state where we work
            # on the same position. If required the reload happens at that moment,
            # NOT before the empty transition block.
            #
            # This is not true for Path Walker States, so we offer the option 
            # 'ForceInputDereferencingF'
            assert StateIndex != self.init_state_index # Empty state machine! --> impossible

            if self.engine_type.is_FORWARD(): 
                cmd_ext = [ Op.Increment(E_R.InputP) ]
            else:                             
                cmd_ext = [ Op.Decrement(E_R.InputP) ]
        else:
            if self.engine_type.is_FORWARD(): 
                cmd_ext = [ Op.Increment(E_R.InputP), Op.InputPDereference() ]
            else:                             
                cmd_ext = [ Op.Decrement(E_R.InputP), Op.InputPDereference() ]

        cmd_list.extend(cmd_ext)

        ta = TransitionAction(OpList.from_iterable(cmd_list))

        # NOTE: The 'from reload transition' is implemented by 'prepare_for_reload()'
        for source_state_index in self.__from_db[StateIndex]: 
            assert source_state_index != E_StateIndices.BEFORE_ENTRY
            state.entry.enter(StateIndex, source_state_index, ta.clone())

        if StateIndex == self.init_state_index:
            if self.engine_type.is_FORWARD():
                on_entry_op_list = OnBeforeEntry.clone()
                on_entry_op_list.append(Op.InputPDereference())
                ta = TransitionAction(on_entry_op_list)
            state.entry.enter_state_machine_entry(self.__state_machine_id, 
                                                  StateIndex, ta)

        return state
예제 #2
0
파일: core.py 프로젝트: xxyzzzq/quex
    def prepare_state(self, OldState, StateIndex, OnBeforeEntry):
        """REQUIRES: 'self.init_state_forward_f', 'self.engine_type', 'self.__from_db'.
        """
        state = AnalyzerState.from_State(OldState, StateIndex,
                                         self.engine_type)

        cmd_list = []
        if self.engine_type.is_BACKWARD_PRE_CONTEXT():
            cmd_list.extend(
                Op.PreContextOK(cmd.acceptance_id())
                for cmd in OldState.single_entry.get_iterable(SeAccept))

        if state.transition_map is None and False:
            # NOTE: We need a way to disable this exception for PathWalkerState-s(!)
            #       It's safe, not to allow it, in general.
            #------------------------------------------------------------------------
            # If the state has no further transitions then the input character does
            # not have to be read. This is so, since without a transition map, the
            # state immediately drops out. The drop out transits to a terminal.
            # Then, the next action will happen from the init state where we work
            # on the same position. If required the reload happens at that moment,
            # NOT before the empty transition block.
            #
            # This is not true for Path Walker States, so we offer the option
            # 'ForceInputDereferencingF'
            assert StateIndex != self.init_state_index  # Empty state machine! --> impossible

            if self.engine_type.is_FORWARD():
                cmd_ext = [Op.Increment(E_R.InputP)]
            else:
                cmd_ext = [Op.Decrement(E_R.InputP)]
        else:
            if self.engine_type.is_FORWARD():
                cmd_ext = [Op.Increment(E_R.InputP), Op.InputPDereference()]
            else:
                cmd_ext = [Op.Decrement(E_R.InputP), Op.InputPDereference()]

        cmd_list.extend(cmd_ext)

        ta = TransitionAction(OpList.from_iterable(cmd_list))

        # NOTE: The 'from reload transition' is implemented by 'prepare_for_reload()'
        for source_state_index in self.__from_db[StateIndex]:
            assert source_state_index != E_StateIndices.BEFORE_ENTRY
            state.entry.enter(StateIndex, source_state_index, ta.clone())

        if StateIndex == self.init_state_index:
            if self.engine_type.is_FORWARD():
                on_entry_op_list = OnBeforeEntry.clone()
                on_entry_op_list.append(Op.InputPDereference())
                ta = TransitionAction(on_entry_op_list)
            state.entry.enter_state_machine_entry(self.__state_machine_id,
                                                  StateIndex, ta)

        return state