[m-dev.] record syntax

[Fergus Henderson]

On 29-Nov-2000, Peter Ross <peter.ross at miscrit.be> wrote:
> On Wed, Nov 29, 2000 at 09:39:19AM +1100, Fergus Henderson wrote:
> > On 28-Nov-2000, Peter Ross <peter.ross at miscrit.be> wrote:
> > > I think we should add the following to the record syntax for allowing
> > > the use of the record syntax for abstract types.
> > > 
> > > :- interface.
> > > 
> > > :- type abstract(T) with [field_a, field_b].
> > > 
> > > :- implementation.
> > > 
> > > :- type abstract(T)
> > >     --->    f(
> > >                 field_a :: int,
> > >                 field_b :: int,
> > >                 field_c :: int
> > >             ).
> > > 
> > > Any objections?
> > 
> > Yes: the interface needs to specify the field types.
> > 
> > Are you aware of the existing syntax for this?
> > 
> Yes, but I find the verboseness to be a big drawback.
> 
> How about 
> 
> :- type abstract(T) with [field_a :: int, field_b :: int].

Better, but that still doesn't specify the determinism of the field
access functions.  Note that field access functions can be semidet
(e.g. for discriminated types with more than one alternative).

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
                                    |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.
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