Function Formula_Impl

inst/include/Rcpp/Formula.h:40–67

        Formula_Impl(){} ;

        Formula_Impl(SEXP x){
            switch( TYPEOF( x ) ){
            case LANGSXP:
                if( ::Rf_inherits( x, "formula") ){
                    Storage::set__( x );
                } else{
                    Storage::set__( internal::convert_using_rfunction( x, "as.formula") ) ;
                }
                break;
            case EXPRSXP:
            case VECSXP:
                /* lists or expression, try the first one */
                if( ::Rf_length(x) > 0 ){
                    SEXP y = VECTOR_ELT( x, 0 ) ;
                    if( ::Rf_inherits( y, "formula" ) ){
                        Storage::set__( y ) ;
                    } else{
                        SEXP z = internal::convert_using_rfunction( y, "as.formula") ;
                        Storage::set__( z ) ;
                    }
                } else{
                    throw not_compatible( "cannot create formula from empty list or expression" ) ;
                }
                break;
            default:
                Storage::set__( internal::convert_using_rfunction( x, "as.formula") ) ;
            }
        }

        explicit Formula_Impl( const std::string& code ) {
            Storage::set__( internal::convert_using_rfunction( ::Rf_mkString(code.c_str()), "as.formula") ) ;