ToGrammarRightRG.h

Go to the documentation of this file.

 
#pragma once
 
#include <grammar/Regular/LeftRG.h>
#include <grammar/Regular/RightRG.h>
 
#include <common/createUnique.hpp>
 
namespace grammar {
 
namespace convert {
 
class ToGrammarRightRG {
public:
    template < class TerminalSymbolType, class NonterminalSymbolType >
    static grammar::RightRG < TerminalSymbolType, NonterminalSymbolType > convert(const grammar::LeftRG < TerminalSymbolType, NonterminalSymbolType > & grammar);
};
 
template < class TerminalSymbolType, class NonterminalSymbolType >
grammar::RightRG < TerminalSymbolType, NonterminalSymbolType > ToGrammarRightRG::convert(const grammar::LeftRG < TerminalSymbolType, NonterminalSymbolType > & grammar) {
    // 1.
    NonterminalSymbolType s = common::createUnique( grammar.getInitialSymbol( ), grammar.getNonterminalAlphabet(), grammar.getTerminalAlphabet() );
 
    grammar::RightRG < TerminalSymbolType, NonterminalSymbolType > rrg( s );
 
    for(const auto & nonterminalSymbol : grammar.getNonterminalAlphabet() ) {
        rrg.addNonterminalSymbol( nonterminalSymbol );
    }
 
    rrg.setTerminalAlphabet( grammar.getTerminalAlphabet( ) );
    
    rrg.setGeneratesEpsilon( grammar.getGeneratesEpsilon( ) );
 
    // 2
    for( const auto & rule : grammar.getRules( ) ) {
        const NonterminalSymbolType& lhs = rule.first;
 
        for ( const auto & ruleRHS : rule.second ) {
                if ( ruleRHS.template is < ext::pair < NonterminalSymbolType, TerminalSymbolType > > ( ) ) {
                const ext::pair < NonterminalSymbolType, TerminalSymbolType > & rhs = ruleRHS.template get < ext::pair < NonterminalSymbolType, TerminalSymbolType > > ( );
 
                ext::pair < TerminalSymbolType, NonterminalSymbolType > rightSide = ext::make_pair ( rhs.second, lhs );
                rrg.addRule( rhs.first, std::move ( rightSide ) );
 
                if ( lhs == grammar.getInitialSymbol ( ) )
                    rrg.addRule ( rhs.first, rhs.second );
            } else {
                const TerminalSymbolType & rhs = ruleRHS.template get < TerminalSymbolType > ( );
 
                ext::pair < TerminalSymbolType, NonterminalSymbolType > rightSide = ext::make_pair ( rhs, lhs );
                rrg.addRule ( rrg.getInitialSymbol ( ), std::move ( rightSide ) );
 
                if ( lhs == grammar.getInitialSymbol ( ) )
                    rrg.addRule ( rrg.getInitialSymbol ( ), rhs );
            }
        }
    }
    return rrg;
}
 
} /* namespace convert */
 
} /* namespace grammar */