You need to use JavaScript for this. You could set a new attribute to true or false to tell you if the two attributes are the same. For example:
@set a=2
Try two variables the [same](next, b=2) or [different](next, b=3).
[next]:
set("same", get("a") == get("b"));
a = {a}, b = {b}, same = {same}.
This sets the value of "same" to true or false, depending on whether the values of "a" and "b" are the same.
Live example: http://docs.textadventures.co.uk/squiffy/scratchpad/?gistid=68b9556d84d3ffc127e4&filename=same.squiffy