The docs for Set QUICKFILTERFLAGS are a bit misleading:
Most arguments listed are explicitly [option name]on and [option name]off at the time of writing, making it look like you can toggle options like hidefiles, but have to stick to turning options like regexp on or off explicitly, as there are arguments listed like regexpon and regexpoff but no mention of regexp, for example.
When I tried it, it worked at least as well as regexpon (same goes for eval instead of evalon), which made me think the docs were leaving out the basic case for the two flags I tested.
In Directory Opus 13.10 Build 9004, regexp and eval seem to work.
I guess there is a difference between Set QUICKFILTERFLAGS=set,eval
vs Set QUICKFILTERFLAGS=evalon
and Set QUICKFILTERFLAGS=clear,eval
vs Set QUICKFILTERFLAGS=evaloff
when both evalon and evaloff alone toggle.
Are there implicit states I'm not expecting, like "neither on nor off" and "both on and off"?
Otherwise, I would think that Set QUICKFILTERFLAGS=evaloff and Set QUICKFILTERFLAGS=clear,evalon have the same result, and everything could be used like the first flags: {flag} to toggle, set,{flag} to turn on, clear,{flag} to turn off.
That's why I thought it was weird that the basic case (which I now know is actually not a valid command, despite working) was omitted, and only specifically the cases for turning the flags on and off were mentioned.
When I had trouble getting the on and off cases to work (linked post), I thought the docs were incomplete for sure
Looking at the code, it shouldn't react to regexp or eval on their own at all. They should be ignored entirely, the same as if they weren't specified, or if a random string of text like dsfhfldsajkhf was used instead.