Records with Variant Parts

Record types offer yet another kind of flexibility. A given record may assume various variant forms. This implies that the number and kind of fields may differ among different variables although they are of the same record type. It is obvious that this flexibility also gives rise to programming errors that are difficult to detect. In particular, it is now possible to assume in some part of a program that a variable is of a certain variant, whereas it actually is of another variant. This facility is therefore to be used with great caution.