variant record & cases

["Ricardo H. Medel" <rmedel@cs.stevens-tech.edu>]

I'm reading the book "Essentials of Programming Languages" by Friedman,
Wand and Haynes, 2nd edition, and I'm trying to use DrScheme (version 101,
yes, I know, I know, it's rather old!) to implement the exercises. But I
don't know how to define a "variant record" and how to use an expression
"cases" with it.

In the book the variant record is defined using "define-datatype".

Can someone help me? Thanks, in advance.

Ricardo H. Medel
Stevens Institute of Technology