[Oberon] CASE without ELSE

[Andreas Pirklbauer]

    > > Does it mean that CASE statement for pointer/
    > > record types work like an IF statement?

  > Yes, it is a syntactic sugar for IF/ELSIF
  > and type guard, nothing more.

A key difference to the IF statement

  IF t IS T1 THEN S1
  ELSIF t IS T2 THEN S2
   ...
  END

is that in the CASE statement

   CASE t OF
      T1: S1 |
      T2: S2 | 
       ...
    END

the dynamic type t of the case expression is set to the type of the selected case, i.e. in the statements S1 labeled by T1, the case variable t is considered as of type T1, etc.

This implies that no type guard t(T1) is needed in S1, etc, i.e. one can just write t instead.
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