[Yhc] YHC.Primitive;_E

To get the hang of using Yhc.Core, I'm writing a little haskell interpreter. The interpreter errors out when ever it comes across an unknown primitive. The first such primitive I had to implement was SEQ. Now I'm on to YHC.Primitive;_E. What is the meaning of this type? Is there a place where these primitive types are defined? When I print the coreDatas I see: data YHC.Primitive;_E b = YHC.Primitive;_E b When I print coreFuncs, I see no Case expressions that could extract data put into _E. Thanks for any tips! -Tom