GlushkovFirst.h

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#pragma once
 
#include <alib/set>
#include <common/ranked_symbol.hpp>
 
#include <rte/formal/FormalRTE.h>
 
namespace rte {
 
class GlushkovFirst {
public:
    template < class SymbolType >
    static ext::set < common::ranked_symbol < SymbolType > > first ( const rte::FormalRTE < SymbolType > & rte );
 
    template < class SymbolType >
    class Formal {
    public:
        static ext::set < common::ranked_symbol < SymbolType > > visit ( const rte::FormalRTEAlternation < SymbolType > & node );
        static ext::set < common::ranked_symbol < SymbolType > > visit ( const rte::FormalRTESubstitution < SymbolType > & node );
        static ext::set < common::ranked_symbol < SymbolType > > visit ( const rte::FormalRTEIteration < SymbolType > & node );
        static ext::set < common::ranked_symbol < SymbolType > > visit ( const rte::FormalRTESymbolAlphabet < SymbolType > & node );
        static ext::set < common::ranked_symbol < SymbolType > > visit ( const rte::FormalRTESymbolSubst < SymbolType > & node );
        static ext::set < common::ranked_symbol < SymbolType > > visit ( const rte::FormalRTEEmpty < SymbolType > & node );
    };
};
 
template < class SymbolType >
ext::set < common::ranked_symbol < SymbolType > > GlushkovFirst::first ( const rte::FormalRTE < SymbolType > & rte ) {
    return rte.getRTE ( ).getStructure ( ).template accept < ext::set < common::ranked_symbol < SymbolType > >, GlushkovFirst::Formal < SymbolType > > ( );
}
 
template < class SymbolType >
ext::set < common::ranked_symbol < SymbolType > > GlushkovFirst::Formal < SymbolType >::visit ( const rte::FormalRTEAlternation < SymbolType > & node ) {
    ext::set < common::ranked_symbol < SymbolType > > ret;
    ext::set < common::ranked_symbol < SymbolType > > tmp;
 
    tmp = node.getLeftElement ( ).template accept < ext::set < common::ranked_symbol < SymbolType > >, GlushkovFirst::Formal < SymbolType > > ( );
    ret.insert ( tmp.begin ( ), tmp.end ( ) );
 
    tmp = node.getRightElement ( ).template accept < ext::set < common::ranked_symbol < SymbolType > >, GlushkovFirst::Formal < SymbolType > > ( );
    ret.insert ( tmp.begin ( ), tmp.end ( ) );
 
    return ret;
}
 
template < class SymbolType >
ext::set < common::ranked_symbol < SymbolType > > GlushkovFirst::Formal < SymbolType >::visit ( const rte::FormalRTESubstitution < SymbolType > & node ) {
    ext::set < common::ranked_symbol < SymbolType > > ret;
    ext::set < common::ranked_symbol < SymbolType > > tmp;
 
    tmp = node.getLeftElement ( ).template accept < ext::set < common::ranked_symbol < SymbolType > >, GlushkovFirst::Formal < SymbolType > > ( );
    ret.insert ( tmp.begin ( ), tmp.end ( ) );
 
     // First returns a set. hence only one occurrence.
    auto it = std::find_if ( ret.begin ( ), ret.end ( ), [node] ( const common::ranked_symbol < SymbolType > & a ) {
            return a == node.getSubstitutionSymbol ( ).getSymbol ( );
        } );
 
    if ( it != ret.end ( ) ) {
        ret.erase ( it );
        tmp = node.getRightElement ( ).template accept < ext::set < common::ranked_symbol < SymbolType > >, GlushkovFirst::Formal < SymbolType > > ( );
        ret.insert ( tmp.begin ( ), tmp.end ( ) );
    }
 
    return ret;
}
 
template < class SymbolType >
ext::set < common::ranked_symbol < SymbolType > > GlushkovFirst::Formal < SymbolType >::visit ( const rte::FormalRTEIteration < SymbolType > & node ) {
    ext::set < common::ranked_symbol < SymbolType > > ret;
 
    ret = node.getElement ( ).template accept < ext::set < common::ranked_symbol < SymbolType > >, GlushkovFirst::Formal < SymbolType > > ( );
    ret.insert ( node.getSubstitutionSymbol ( ).getSymbol ( ) );
    return ret;
}
 
template < class SymbolType >
ext::set < common::ranked_symbol < SymbolType > > GlushkovFirst::Formal < SymbolType >::visit ( const rte::FormalRTESymbolAlphabet < SymbolType > & node ) {
    return ext::set < common::ranked_symbol < SymbolType > > { node.getSymbol ( ) };
}
 
template < class SymbolType >
ext::set < common::ranked_symbol < SymbolType > > GlushkovFirst::Formal < SymbolType >::visit ( const rte::FormalRTESymbolSubst < SymbolType > & node ) {
    return ext::set < common::ranked_symbol < SymbolType > > { node.getSymbol ( ) };
}
 
template < class SymbolType >
ext::set < common::ranked_symbol < SymbolType > > GlushkovFirst::Formal < SymbolType >::visit ( const rte::FormalRTEEmpty < SymbolType > & /* node */ ) {
    return ext::set < common::ranked_symbol < SymbolType > > ( );
}
 
} /* namespace rte */