How do I access instance variable by name

for x=1 to 10  
   monster.Variable("param" & loopindex) = random(1000)[/code:2fnu5ayr]
instead of 
[code:2fnu5ayr]monster.param1= random(1000)
monster.param2= random(1000)
monster.param3= random(1000)
monster.param4= random(1000)
...
monster.param10= random(1000)[/code:2fnu5ayr]

Another example:
[code:2fnu5ayr]if monster.Shield>0 then MyVar="Shield"
   else if monster.Armor>0 then MyVar="Armor"
         else MyVar="Health"

monster.Variable(MyVar) =  // some complex calculations here to apply damage to monster's shield or armor or base health[/code:2fnu5ayr]

I'm guessing there is no built-in functionality for this.. Maybe there is a plugin or some workaround?