swlaschin

// General hints on defining types with constraints or invariants
// 
// Just as in C#, use a private constructor 
// and expose "factory" methods that enforce the constraints
//
// In F#, only classes can have private constructors with public members. 
//
// If you want to use the record and DU types, the whole type becomes
// private, which means that you also need to provide:
// * a constructor function ("create").