//if (ab isin ;ab) echo $v1 . $v2 .
//if (; isin ; ) echo $v1 . $v2 .

Seems easy enough, but mIRC 6.16 gives * /if: invalid format
If the ; is the first character after the comparison operator, the /if apparently always fails...

(Hope this hasn't been brought up before, searching for ";" seemed troublesome wink )