public vDescriptor Index(vValue i) {
public vDescriptor Index(vDescriptor i) {
public vDescriptor Index(vValue i) {			// s[i]    this.strval();	// validate    int m = this.posEq(i.mkInteger().value);    if (m == 0) {	return null; /*FAIL*/    }    return vSubstring.New(var, m, m+1);}