/click [mod,@player][@mouseover,help][@target,help][@targettarget,help][] MultiBarLeftButton3;
I think that would work is MultiBarLeftButton3 held max rank Regrowth from spellbook. I never use mouseover but found an old macro from a level 40ish druid in SoM
#showtooltip [help]Rejuvenation;[mod:shift]Moonfire(Rank 6);Moonfire
/startattack [harm]
/cast [mod:shift,harm]Moonfire(Rank 6);[harm]Moonfire
/stopmacro [nohelp][dead]
/click [mod:shift] MultiBarLeftButton4; MultiBarLeftButton3
I also had a eat/drink macro on my hunter that took into account current hp/mp and pet happiness as a chain of 3 clicks.
/run w,f,u,t,c,l="item:1645","/use item:13930\n","item:8077","/cast Feed Pet\n/use item:13930\n","P"
/run g=((GetItemCount(u)>0) and u or w)
/run g=g.."\n"
/run EditMacro(c,c,nil,"#showtooltip "..g)
/run g="/use "..g
/click MultiBarLeftButton5
/run e=GetPetHappiness() if(e==nil) then l="" elseif e<3 then l=t end;
/run h=((UnitHealth("player")/UnitHealthMax("player")*100)<85 and f)
/run m=((UnitPower("player")/UnitPowerMax("player")*100)<85 and g)
/click MultiBarLeftButton6
/run local d=GetMacroBody(c)EditMacro(c,c,nil,d..l)
/run local d=GetMacroBody(c)EditMacro(c,c,nil,d..h)
/run local d=GetMacroBody(c)EditMacro(c,c,nil,d..m)
/click MultiBarBottomLeftButton12
It did calculations to edit the food/water macro and then click it after it had been edit’d. Was years ago. The macro being edit’d had to be named “P” (defined as global variable c in first line). The global variable l was set to null as a way to reset macro to empty before repopulating it.
done editting sorry formatting was tough