Re: ISO Open Array Parameters

In article <461B5214.1214.0092.0@[EMAIL PROTECTED]
>,
   Tom Breeden <tmb@[EMAIL PROTECTED]
> wrote:

> 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.

     This was the subject of some considerable debate in the WG meetings,
but the reason given was that in order to assign to such an array it must
be known statically that the argument has enough space. If it hasn't the
only option is to abort the assignment - which is not in the spirit of
Modula-2 since it requires run-time checks.

     The alternative is to create space 'magically' without the programmer
specifically allocating storage - another no-no in an M2 environment.

     The philosophy of Modula-2 is that it is a language in which nothing
happens under the covers - everything should be explicitly written by the
program/module author.

     There is, therefore, nothing wrong per se in making such assignment -
it is after all done in other languages - but cannot be done in a 'Modula
2
way' - hence is not permitted in the standard.

     There was some initial grumbling, but this rationale seems to retain
the intention of Wirth when originally designing the language suitable for
low-level system software as well as for higher level programs.

                         Keith

-- 
Inspired!