Evaluate generalized linear model with categorical variables

I'm using Matlab 2016a and I'm experiencing some issues with it: I have estimated a generalized linear model using categorical variables; however, I don't know how to evaluate it on unseen data, since the function glmval takes as inputs only vectors and matrices... How can I circumvent the problem? I would try to write a function for doing this by myself, but I think that it will take me ages... Maybe a clever written line of code that relates my input dataset ds with the table in mdl.Coefficients.Estimate will do the work, but I don't really know how to achieve this...