Hello. I am writing a Haskell program based on some guidelines written for Standard ML (The Tiger compiler from the "Modern Compiler Implementation in ML" book). The author uses modules for abstracting things like specifities of the taraget machine. For intance, there is a general Frame signature that abstracts the frame representation which depends on the target machine. For each target machine there is a structure compliant to that signature. For instante MipsFrame, PentiumFrame and SparcFrames would be structures implementing the Frame signature. Many parts of the program just see the Frame signature. Is there any guidelines on how to achieve somethying similar to this in Haskell? Regards, Romildo