mIRC Homepage

$submenu double evaluate

Posted By: Wims

$submenu double evaluate - 03/03/22 10:15 PM

It does not seem to be useful for the $submenu mechanism to re-evaluate the content that is returned by the alias and it does not seem to be forced like in /timer or /scid:

menu menubar {
  double evaluation
alias testsm {
if ($1 == 1) return item : echo -ag > $!!me
Inside a script $!me means plain text "$me", so if someone is using $!me there, they would expect plain text "$me".
If there's no good reason for this behavior, could it be changed? Even if it's been in place for so long, double evaluating is not something you want, it can be exploited etc.
Posted By: Khaled

Re: $submenu double evaluate - 05/03/22 06:25 PM

Thanks for your bug report. This is intentional and is by design and cannot be changed. It is the same issue as double-evaluation in many other scripting contexts. Scripters need to be aware of situations where this can happen and need to cater for it.
Posted By: Wims

Re: $submenu double evaluate - 05/03/22 09:51 PM

 It is the same issue as double-evaluation in many other scripting contexts

To elaborate on that, there aren't that many double-evaluating scripting context, the one known are listed on wikichip: https://en.wikichip.org/wiki/mirc/msl_injection

/timer, /dde, /scon and /scid include a command, we can understand the scripting engine will be run twice: the double evaluation is unavoidable (switches were requested to prevent that but from the engine's point of view it's normal)

/flash does not take a command, but it includes a text that will be used later, it's less intuitive but ok, there could be a lot of time before a flash occurs after /flash has been executed, so it makes sense to reevaluate if you want to display real time informations.

But the $submenu context, everything happens at the same time as far as the scripter is concerned, so it's not like your real time informations will change much during the scope of $submenu.. besides $ticks and $ticksqpc..!?
It's always possible to use % $+ global variable as a returned value and set that variable afterward to get the desired result but it seems like it's not required at all, I don't think anyone knew about this to begin with, and there don't seem to be real benefit from double evaluating here

I could be wrong but I believe that all double evaluation contexts happen because the scripting engine is being called twice on the string, it's obvious for /timer etc, it's less obvious why it occurs on $submenu, to me, or even the $calc bit.

I suppose this is too old behavior to change anyway, but since double evaluation does not occur except in specific cases, it would be nice to have a note in the help file about these contexts because it's dangerous, I don't know if anyone knew about this one to be honnest, I'll add $submenu to the wikichip page.
© 2022 mIRC Discussion Forums