In gp:  I have a boolean function GreaterThan that I use to compare two variables, but I want to make sure that I am not comparing the same two variables.  In other words,

> var1  var2  is ok, and
> var1  var2  is ok, but
> var1 var1 is not ok, and
> var2 var2 is not ok either.

Here is the node constraint for the boolean function (from params file):

gp.nc.4 = ec.gp.GPNodeConstraints
gp.nc.4.name = ncBool-Child1Nil-Child2Nil
gp.nc.4.returns = bool
gp.nc.4.size = 2
gp.nc.4.child.0 = nil
gp.nc.4.child.1 = nil

Is there a way to restrict this behavior in the params file?  The children will be of the same type, but can't be the same variable.  Or do I have to do something in the checkConstraints method of the GPNode?

Shane