Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!clyde!uunet!mcsun!cernvax!ethz!marti
From: marti@ethz.UUCP (Robert Marti)
Newsgroups: comp.lang.modula2
Subject: Re: MetCom (actually: NEW & DISPOSE)
Message-ID: <2736@ethz.UUCP>
Date: 5 Dec 89 17:11:07 GMT
References: <891204.13351181.096571@UWEC.CP6>
Organization: ETH Zuerich
Lines: 53

In article <891204.13351181.096571@UWEC.CP6>, S703975@UWEC.BITNET
(ANDREW TREMBLEY) writes:
> My problem is that whenever I try a NEW or a DISPOSE the compiler barfs.
> I assume that this is because it has to be imported from a module, but
> I have no idea which one.

Let me start with a disclaimer:  I have never used MetCom Modula-2.
I do know a couple of other Modula-2 implementations though, in
particular the MacMETH system on which MetCom M-2 is based, I believe.

The book "Programming in Modula-2, 3rd Ed." by N.Wirth, p.76, states
(emphasis added by me):

    [Pointer variables] are created by a call of an allocation
    procedure, usually available from a library module.  TYPICALLY,
    a module Storage may provide a procedure Allocate.  The state-
    ment  Allocate(p0, SIZE(Node))  then creates a variable of type
    Node and assigns a pointer pointing to that variable to [...] p0.

and, a little later:

    In SOME implementations, the statement  Allocate(p0, SIZE(Node))
    can be abbreviated as  NEW(p0) .

Assuming that this is all true for MetCom M-2 -- which may well not
be the case -- you'd have to import Allocate from Storage anyway,
EVEN WHEN using the abbreviation NEW.  However, it is not entirely
clear which of the two solutions below work:

    FROM Storage IMPORT Allocate;
    VAR p: POINTER TO ... ;
    ...
    NEW(p);

or

    IMPORT Storage;
    VAR p: POINTER TO ... ; 
    ...   
    NEW(p);

Note that in the MacMETH system, there is a module Storage which exports
ALLOCATE (!) and DEALLOCATE and a module System (!) which exports Allocate
and Deallocate.  NEW is not supported.

So, check the documentation to figure out from which module either
Allocate or ALLOCATE is exported.  Then check if NEW is supported.
I hope this helps.
-- 
Robert Marti                      Phone:      +41 1 256 52 36
Institut fur Informationssysteme
ETH-Zentrum                       CSNET/ARPA: marti%inf.ethz.ch@relay.cs.net
CH-8092 Zurich, Switzerland       UUCP:       ...uunet!mcvax!ethz!marti