/* // generic unoptimized versions
function sc_assX(o, al, comp) {
while (al != null) {
if (comp(al.car.car, o))
return al.car;
al = al.cdr;
}
return false;
}
function sc_assq(o, al) { return sc_assX(o, al, sc_isEq); }
function sc_assv(o, al) { return sc_assX(o, al, sc_isEqv); }
function sc_assoc(o, al) { return sc_assX(o, al, sc_isEqual); }
 optimized versions * META ((export #t))
function sc_assq(o, al) {
    while (al !== null) {
	if (al.car.car === o)
	    return al.car;
	al = al.cdr;
    }
    return false;
}