ISO Open Array Parameters

Hi all,

I've just noticed that ISO M2 specifies that it is never allowed to assign
to an open array parameter as a whole
while within the called procedure.

eg,

      PROCEDURE P(VAR a:ARRAY OF CHAR);
     BEGIN

     a := "a string";

     END P;

is not allowed.

That seems a bit odd, considering a string literal can be assigned to any
other character array variable, no matter what the declared size.

It does not seem to pose implementation difficulties for the compiler,
since
the HIGH value is at a known place on the stack.

I must be overlooking the rationale? What was the thinking on this?

Thanks,

Tom