ToPostfixPushdownAutomaton.h

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/*
 * This file is part of Algorithms library toolkit.
 * Copyright (C) 2017 Jan Travnicek (jan.travnicek@fit.cvut.cz)
 
 * Algorithms library toolkit is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 
 * Algorithms library toolkit is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 
 * You should have received a copy of the GNU General Public License
 * along with Algorithms library toolkit.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include <automaton/TA/DFTA.h>
#include <automaton/TA/NFTA.h>
#include <automaton/PDA/NPDA.h>
#include <automaton/PDA/DPDA.h>
 
#include <alphabet/BottomOfTheStackSymbol.h>
#include <alphabet/EndSymbol.h>
 
namespace automaton {
 
namespace convert {
 
class ToPostfixPushdownAutomaton {
public:
    template < class SymbolType, class StateType >
    static automaton::DPDA < ext::variant < common::ranked_symbol < SymbolType >, alphabet::EndSymbol >, ext::variant < StateType, alphabet::BottomOfTheStackSymbol >, char > convert ( const automaton::DFTA < SymbolType, StateType > & dfta );
 
    template < class SymbolType, class StateType >
    static automaton::NPDA < ext::variant < common::ranked_symbol < SymbolType >, alphabet::EndSymbol >, ext::variant < StateType, alphabet::BottomOfTheStackSymbol >, char > convert ( const automaton::NFTA < SymbolType, StateType > & nfta );
};
 
template < class SymbolType, class StateType >
automaton::DPDA < ext::variant < common::ranked_symbol < SymbolType >, alphabet::EndSymbol >, ext::variant < StateType, alphabet::BottomOfTheStackSymbol >, char > ToPostfixPushdownAutomaton::convert ( const automaton::DFTA < SymbolType, StateType > & dfta ) {
    automaton::DPDA < ext::variant < common::ranked_symbol < SymbolType >, alphabet::EndSymbol >, ext::variant < StateType, alphabet::BottomOfTheStackSymbol >, char > automaton ( 'q', alphabet::BottomOfTheStackSymbol ( ) );
 
    for ( const auto & rankedSymbol : dfta.getInputAlphabet ( ) ) {
        automaton.addInputSymbol ( rankedSymbol );
    }
    automaton.addInputSymbol ( alphabet::EndSymbol ( ) );
 
    for ( const StateType & state : dfta.getStates ( ) ) {
        automaton.addPushdownStoreSymbol ( state );
    }
 
    for (const auto & transition : dfta.getTransitions()) {
        ext::vector < ext::variant < StateType, alphabet::BottomOfTheStackSymbol > > pop ( transition.first.second.rbegin ( ), transition.first.second.rend ( ) );
        ext::vector < ext::variant < StateType, alphabet::BottomOfTheStackSymbol > > push ( 1, transition.second );
        automaton.addTransition ( automaton.getInitialState ( ), transition.first.first, pop, automaton.getInitialState ( ), push );
    }
 
    auto finalPDAState = 'r';
    automaton.addState ( finalPDAState );
    automaton.addFinalState ( finalPDAState );
 
    for ( const auto & finalState : dfta.getFinalStates ( ) ) {
        ext::vector < ext::variant < StateType, alphabet::BottomOfTheStackSymbol > > pop = { finalState, alphabet::BottomOfTheStackSymbol ( ) };
        ext::vector < ext::variant < StateType, alphabet::BottomOfTheStackSymbol > > push;
        automaton.addTransition ( automaton.getInitialState ( ), alphabet::EndSymbol ( ), pop, finalPDAState, push );
    }
 
    return automaton;
}
 
template < class SymbolType, class StateType >
automaton::NPDA < ext::variant < common::ranked_symbol < SymbolType >, alphabet::EndSymbol >, ext::variant < StateType, alphabet::BottomOfTheStackSymbol >, char > ToPostfixPushdownAutomaton::convert ( const automaton::NFTA < SymbolType, StateType > & nfta ) {
    automaton::NPDA < ext::variant < common::ranked_symbol < SymbolType >, alphabet::EndSymbol >, ext::variant < StateType, alphabet::BottomOfTheStackSymbol >, char > automaton ( 'q', alphabet::BottomOfTheStackSymbol ( ) );
 
    for ( const auto & symbol : nfta.getInputAlphabet ( ) ) {
        automaton.addInputSymbol ( symbol );
    }
    automaton.addInputSymbol ( alphabet::EndSymbol ( ) );
 
    for ( const StateType & state : nfta.getStates ( ) ) {
        automaton.addPushdownStoreSymbol ( state );
    }
 
    for ( const auto & transition : nfta.getTransitions ( ) ) {
        ext::vector < ext::variant < StateType, alphabet::BottomOfTheStackSymbol > > pop ( transition.first.second.rbegin ( ), transition.first.second.rend ( ) );
        ext::vector < ext::variant < StateType, alphabet::BottomOfTheStackSymbol > > push ( 1, transition.second );
        automaton.addTransition (automaton.getInitialState ( ), transition.first.first, pop, automaton.getInitialState ( ), push );
    }
 
    char finalPDAState = 'r';
    automaton.addState ( finalPDAState );
    automaton.addFinalState ( finalPDAState );
 
    for ( const StateType & finalState : nfta.getFinalStates ( ) ) {
        ext::vector < ext::variant < StateType, alphabet::BottomOfTheStackSymbol > > pop = { finalState, alphabet::BottomOfTheStackSymbol ( ) };
        ext::vector < ext::variant < StateType, alphabet::BottomOfTheStackSymbol > > push;
        automaton.addTransition ( automaton.getInitialState ( ), alphabet::EndSymbol ( ), pop, finalPDAState, push );
    }
 
    return automaton;
}
 
} /* namespace convert */
 
} /* namespace automaton */