If you are looking for trigger macros with your equations you should have a look at cadsharp.com. By doing that you could have macros that does some kind of a job for you.
You should also investigate if this is still supported in SolidWorks 2015. Not sure why, but I have a feeling of that I read somewhere that trigger macros in equations was not longer supported in SW2015. I hope that I'm wrong... but is better that you check it up before you spend time on a solution like that.
Another idea would be to create a add-in with VB or C++/C#. I would say that if you are going to distribute to automation among many users and also create some user interfaces, then a add-in is most recommended.
For reference, in 2015 you can still get it to work, by putting the code snippet into a custom property.
Then create an equations.txt file containing an equation similar to this: "globalvar" = "custompropname"
Import that equation and it should run the macro on rebuild.