🚀 go-pugleaf

Harvard Townsend recently communicated about the types of the
expressions used in a FOR statement.

Suppose that we are dealing with the FOR statement:
      FOR v := A TO B BY C DO SS END
The original definition of Modula-2 (see, for example, page 154 of the
2nd edition of "Programming in Modula-2" (PIM)) states:
      "A and B must be assignment compatible with v".

However, it was pointed out that the comparison of the control variable
and the final value is difficult to implement when one is of type INTEGER
and the other is of type CARDINAL.   Hence, in the 3rd edition of PIM
(page 158), Wirth has:
      "A and B must be compatible with v".
Thus, according to this definition, the mixing of INTEGER and CARDINAL
is not allowed.

Subsequently, it has been argued that this change need only have been made
for the final value, i.e.,
      "A must be assignment compatible and B must be compatible with v".

Currently, the standardisation groups have a position which agrees with
the 3rd edition of PIM.
==
Barry Cornelius
==
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