MACRO expansion operator trap

[jj2007]

I have two macros, AnyMacro and JJ$. Consider this line inside a third macro:

% AnyMacro AnyArg      ;; AnyMacro allows JJ$(ct-1)

While the line looks pretty harmless, the part marked in red behind a double ;; is actually being executed as JJ$(ct-1).
Without the expansion operator, it is just a comment.

It cost me a while to find out "who" generated this extra code (it crashed my app), so I thought I should share this with the MACRO crowd :wink

[qWord]

wow, what a bug! Or feature ?
... a new operator is born:

%;    expand function like macro and discard return value

:U

[hutch--]

 :bg