Macro to subtract damage from target

Maybe I just cant find it, but I cant seem to figure out a way to make it so macros can subtract damage from a bar of a target. I can make it prompt them to pick a target, and to read the bar value..but not to reduce that bar. For example say Player A wants to attack Goblin A. Is there a way to do an @{selected|bar1} in the macro to take his damage roll, and subtract it from the Bar1 on the goblin?

William R. said: Is there a way to do an @(something) in the macro to take his damage roll, and subtract it from the Bar1 on the goblin? Nope. You'd need to use the API for that, something about which I know next to nothing. But I'm sure someone more knowledgeable than I will be along shortly...

Hmm I could probably figure it out in the API then :( just was hoping with all the macro options, that one would be in there. It would double our combat round speeds :) less clicking, typing, and such for me each time someone attacks.

Unfortunately, Macro's are strictly read-only. They can't modify values.

There are several different threads in the API forum for combat systems based on which system you are using. It's the only way that is going to happen