Updating Macro Buttons Using Macros
Dynamically Updating a Token's Macro Buttons
Some times you want to modify the label of a Token's macro button from within a macro; this could be to visually represent a spell or power as having been used or even indicating that it is available for use.
A quick note on some of these examples: before 1.3b51 it was only possible to have 2 levels deep of code: blocks, so some of the examples do things a little differently than you would if you could have multiple levels of code: blocks to avoid running into the problem. Also before 1.3b50 there was no way to get the index of the button that had been pressed, these tutorials show you how to "guess" the button that is pressed. As of 1.3b50 you can use the function getMacroButtonIndex() to determine exactly which macro button has been clicked on the token.
This tutorial is broken into several parts; although DnD4e is used to explain the concepts they are just as valid for any other system where you want to track if a skill has already been used or not.