Promise.cpp

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// -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; indent-tabs-mode: nil; -*-
//
// Promise.h: Rcpp R/C++ interface class library -- promises (PROMSXP)
//
// Copyright (C) 2010 - 2011 Dirk Eddelbuettel and Romain Francois
//
// This file is part of Rcpp.
//
// Rcpp 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 2 of the License, or
// (at your option) any later version.
//
// Rcpp 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 Rcpp.  If not, see <http://www.gnu.org/licenses/>.

#include <Rcpp/Promise.h>

namespace Rcpp {

    Promise::Promise(SEXP x) : RObject(){
        if( TYPEOF(x) == PROMSXP ){
            setSEXP( x ) ;
        } else{
            throw not_compatible("not a promise") ;
        }
    }

    Promise::Promise(const Promise& other) : RObject() {
        setSEXP( other.asSexp() );
    }
        
    Promise& Promise::operator=(const Promise& other){
        setSEXP( other.asSexp() );
        return *this ;
    }
        
    int Promise::seen() const {
        return PRSEEN(m_sexp);
    }

    SEXP Promise::value() const {
        SEXP val = PRVALUE(m_sexp) ; 
        if( val == R_UnboundValue ) throw unevaluated_promise() ;
        return val ;
    }
        
    bool Promise::was_evaluated() const {
        return PRVALUE(m_sexp) != R_UnboundValue ;
    }

    Environment Promise::environment() const {
        return Environment(PRENV(m_sexp)) ;
    }

    ExpressionVector Promise::expression() const {
        return ExpressionVector(PRCODE(m_sexp)) ;
    }
        
} // namespace