nasm treats negative numbers as non numbers!

[nobody]

try doing this

%ifnnum -1
  %error "-1 is not a number."
%endif

[Frank Kotler]

Yeah, Nasm's a little brain-dead on this issue - just looks to see if the *first* character's a decimal digit. The "workaround" is to use "0-1" - kinda ugly, but you get used to it :)

We may get that fixed... someday... it's easy to get used to, honest! (if it wasn't, I suppose it would have been fixed by now :)

Best,
Frank

[nasm64developer]

> Yeah, Nasm's a little brain-dead on this issue

No, it isn't. Instead the NASM preprocessor is
behaving as expected. The term "-1" consists of
two tokens, "-" and "1". And "-" isn't a number.

> We may get that fixed

Doing so would break the preprocessor's logic.
As well as backwards compatibility.

[nobody]

0y is also a number for nasm's preprocessor.
Very its preprocessor's logic is quite other than its assembler's logic.

%ifnum 0y
%error 0y is a number
%endif