aureooms/js-pn

var pull = function ( compile , isop , token , stack , count ) {

    var state ;

    stack.push( token ) ;

    if ( isop( token ) ) {

        count.push( 0 ) ;
        return false ;

    }

    while ( true ) {

        state = count.pop( ) + 1 ;
        count.push( state ) ;

        if ( state < 2 ) return false ;

        b  = stack.pop( ) ;
        a  = stack.pop( ) ;
        op = stack.pop( ) ;

        stack.push( compile( op , a , b ) ) ;
        count.pop( ) ;

        if ( count.empty( ) ) return true ;

    }

} ;

exports.pull = pull ;