<filename>fla/pda/instance.py<gh_stars>0
# -*- coding: utf-8 -*-

# Copyright (c) 2019 <NAME>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import copy

from fla.pda.transition import Transition


class Instance:
    def __init__(self, automaton, state, word, stack, previous_configuration = None):
        self.automaton = automaton
        self.current_state = state
        self.current_word = word
        self.current_stack = stack
        self.acceptance_status = None
        self.previous_configuration = previous_configuration

    def __is_transition_valid(self, transition):
        if len(self.current_word) == 0:
            current_symbol = None
        else:
            current_symbol = self.current_word[0]
        return transition.match(self.current_state, current_symbol, self.current_stack)

    def __str__(self):
        result = "["
        result += self.current_word + ", "
        result += "".join(self.current_stack)[::-1] + ", "
        result += "]@S"
        result += self.current_state
        return result
    
    def __eq__(self, other):
        if self.__class__ != other.__class__:
            return False
        if self.current_state != other.current_state:
            return False
        if self.current_word != other.current_word:
            return False
        if self.current_stack != other.current_stack:
            return False
        return True

    def get_valid_transitions(self):
        valid_transitions = []
        for transition in self.automaton.transitions:
            if self.__is_transition_valid(transition):
                valid_transitions.append(transition)
        return valid_transitions
        
    def apply_transition(self, transition):
        if not self.__is_transition_valid(transition):
            return None
        if transition.has_empty_word_symbol():
            new_word = self.current_word
        else:
            new_word = self.current_word[1:]
        new_stack = copy.copy(self.current_stack) 
        if not transition.has_empty_current_stack_symbols():
            for symbol in transition.current_stack_symbols:
                new_stack.pop()
        if not transition.has_empty_new_stack_symbols():
            for symbol in transition.new_stack_symbols[::-1]:
                new_stack.append(symbol)
        new_instance = Instance(self.automaton, transition.new_state, new_word, new_stack, self)
        return new_instance

<filename>fla/pda/instance.py<gh_stars>0
# -*- coding: utf-8 -*-

# Copyright (c) 2019 <NAME>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import copy

from fla.pda.transition import Transition


class Instance:
    def __init__(self, automaton, state, word, stack, previous_configuration = None):
        self.automaton = automaton
        self.current_state = state
        self.current_word = word
        self.current_stack = stack
        self.acceptance_status = None
        self.previous_configuration = previous_configuration

    def __is_transition_valid(self, transition):
        if len(self.current_word) == 0:
            current_symbol = None
        else:
            current_symbol = self.current_word[0]
        return transition.match(self.current_state, current_symbol, self.current_stack)

    def __str__(self):
        result = "["
        result += self.current_word + ", "
        result += "".join(self.current_stack)[::-1] + ", "
        result += "]@S"
        result += self.current_state
        return result
    
    def __eq__(self, other):
        if self.__class__ != other.__class__:
            return False
        if self.current_state != other.current_state:
            return False
        if self.current_word != other.current_word:
            return False
        if self.current_stack != other.current_stack:
            return False
        return True

    def get_valid_transitions(self):
        valid_transitions = []
        for transition in self.automaton.transitions:
            if self.__is_transition_valid(transition):
                valid_transitions.append(transition)
        return valid_transitions
        
    def apply_transition(self, transition):
        if not self.__is_transition_valid(transition):
            return None
        if transition.has_empty_word_symbol():
            new_word = self.current_word
        else:
            new_word = self.current_word[1:]
        new_stack = copy.copy(self.current_stack) 
        if not transition.has_empty_current_stack_symbols():
            for symbol in transition.current_stack_symbols:
                new_stack.pop()
        if not transition.has_empty_new_stack_symbols():
            for symbol in transition.new_stack_symbols[::-1]:
                new_stack.append(symbol)
        new_instance = Instance(self.automaton, transition.new_state, new_word, new_stack, self)
        return new_instance

# -*- coding: utf-8 -*- # Copyright (c) 2019 <NAME> # # Permission is hereby granted, free of charge, to any person obtaining a copy # of this software and associated documentation files (the "Software"), to deal # in the Software without restriction, including without limitation the rights # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell # copies of the Software, and to permit persons to whom the Software is # furnished to do so, subject to the following conditions: # # The above copyright notice and this permission notice shall be included in all # copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE # SOFTWARE.