$isid
From Scriptwiki
Returns $true if the alias was called as an identifer, otherwise will return $false.
$isid
Example
alias chans { if (!$isid) { echo $color(info) -ag Can not call /chans, this alias must be called like $chans } var %i = $chan(0) while (%i) { var %chans = $addtok(%chans,$chan(%i),44) dec %i } return %chans }