Based on my own experience (and others), I recommend that you have a basic set of fundamental types that you can compose to other types (structures, records) and sequences (arrays). Be careful with enumerations (an anachronism from the time when each byte did count - use strings instead), inheritance and polymorphism (even when XML supports it).
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Building a Better World in your Backyard by Paul Wheaton and Shawn Klassen-Koophttps://coderanch.com/wiki/718759/books/Building-World-Backyard-Paul-Wheaton