/help $iif
That will tell you what you need to know.
Personally I only like to use $iif if it is neccesary. There are many times when an if,then,else statement is neccsary on one line.
It's quicker and mroe stable to say.
if (#chan = $active) do this
else do this
Or I'll set a variable.
var %x
if (compairson is true) %x = $ifmatch
else %x = $false
set %variable %x