Re: Syntax for tagged record types (was Re: Not intended for use in medical,)

[jsa@alexandria (Jon S Anthony)]

In article <mheaney-ya023680002305972133010001@news.ni.net> mheaney@ni.net (Matthew Heaney) writes:

> >For limited types, the only way around this is to hide them behind
> >access types for them.  Then things again work just fine - except for
> >storage management issues.  Hence, the need for GC.  Limited types are
> >really extremely useful.  Unfortunately, much of this is lost without
> >GC support.
> 
> But I'm trying to avoid using any heap.  If I have to allocate an object,
> I'd rather it go on the stack.  Limitedness forces me to put the object on
> the heap.  Why?  

Who said it forces you to put them on the heap?  It's your wanting to
have all sorts of "constructors" for them with all sorts of parameters
and named all sorts of ways and such that basically makes this
necessary.


> It's just a syntactic quirk of the language (the confusion
> of assignment and initialization) that prevents me from initializing a

So, why are you using limited types anyway?


> If we could eliminate those times when a limited object must be put
> on the heap, then there would be less motivation for a garbage
> collector.

Talk about having the cart before the horse!


> It's not clear to me, though, why you even need GC support.   If heap is
> needed to implement an abstraction, the abstraction writer can sweat all
> the memory management details by using storage pools and controlled types. 
> What's the problem?

Go ask a typical C or C++ programmer for starters.  Highly threaded
and interconnected structures are extremely common and are often the
best (most natural, most efficient, most flexible, etc) implmentations
of many abstractions.  Such structures basically _require_ heap style
allocation and reference interconnection.  Sure, it is _possible_ to
manage this sort of complexity by hand, but it is extremely time
consuming grunt type work - the very thing that computers are good at!
That's the problem and that's the reason why GC is so useful.

Why use the stack?  Just allocate everything statically like old
Fortran.  Hey, you can make this work for anything - who needs all
that assistance you get with stack allocation?

/Jon
-- 
Jon Anthony
Organon Motives, Inc.
Belmont, MA 02178
617.484.3383
jsa@organon.com