[m-rev.] For review: add reference in "Promising purity" section

[Ralph Becket]

Mark Brown, Friday, 25 May 2007:
> On 25-May-2007, Ralph Becket <rafe at csse.unimelb.edu.au> wrote:
> > Estimated time taken: 0.1
> > Branches: main
> > 
> > doc/reference_manual.texi:
> > 	Add a reference to the promise_purity scopes described in
> > 	the `Goals' section of the reference manual, from the
> > 	`Promising purity' section.
> > 
> > Index: reference_manual.texi
> > ===================================================================
> > RCS file: /home/mercury1/repository/mercury/doc/reference_manual.texi,v
> > retrieving revision 1.390
> > diff -u -r1.390 reference_manual.texi
> > --- reference_manual.texi	4 Apr 2007 04:38:49 -0000	1.390
> > +++ reference_manual.texi	25 May 2007 02:35:16 -0000
> > @@ -9139,12 +9139,16 @@
> >  Programmers should be very careful about mixing code that is promised
> >  pure with impure predicates or functions that may manipulate the
> >  same hidden state (for example, the impure predicates used to implement 
> > -a predicate that is promised pure); the @samp{promise pure} declaration
> > +a predicate that is promised pure); the @samp{promise_pure} declaration
> >  is supposed to promise that impure code cannot change the declarative
> >  semantics of pure code.  The module system can be used to minimize the
> >  possibility of making errors with such code, by keeping impure
> >  predicates or functions behind the interface where code is promised
> >  pure.
> > +
> > +Note that @code{promise_purity} pragmas are largely redundant due to 
> > +the @samp{promise_pure}, @samp{promise_semipure}, and @samp{promise_impure}
> > +casts described in @ref{Goals}.
> 
> It is misleading to suggest they are redundant.  The casts can't cover
> headvar unifications, so the pragmas are the only way to reach these at the
> moment.

How about this?

Note that the @samp{promise_pure}, @samp{promise_semipure}, and
@samp{promise_impure} casts described in @ref{Goals} may be used to
promise purity at the finer level of goals within clauses.

-- Ralph
--------------------------------------------------------------------------
mercury-reviews mailing list
Post messages to:       mercury-reviews at csse.unimelb.edu.au
Administrative Queries: owner-mercury-reviews at csse.unimelb.edu.au
Subscriptions:          mercury-reviews-request at csse.unimelb.edu.au
--------------------------------------------------------------------------