>Then, why VFP fire a error with this ?
>
>

>x=RTRIM(NULL)
>x=NULL
>? x+1
>

For the same simple reason that it does it in your other example. You can't add to a null value. However, RTRIM() and some other functions have some null support and doesn't trigger an error, just returning null instead.

I guess you wanted that EVALUATE behaves the same way. You can ask for it on the VFP Wish List.

See you,