if (i1 == 0 || i2 == 0) { return null; }
    vDescriptor function(vDescriptor[] args) {	String s1 = vString.argVal(args, 0);	vString s2 = iRuntime.argSubject(args, 1);	int i1 = s2.posEq(iRuntime.argPos(args, 2));	int i2 = s2.posEq(vInteger.argVal(args, 3, 0));	if (i1 > i2) {		int tmp = i1;		i1 = i2;		i2 = tmp;	}	if (i1 > i2-s1.length()) {	    return null;	}	if (s2.value.length() < i1+s1.length()-1) {	    return null;	}	if (s1.equals( s2.value.substring(i1-1, i1+s1.length()-1) )) {	    return iNew.Integer(i1+s1.length());	} else {	    return null;	}    }