[m-dev.] for review: changes to library/map.m

[Fergus Henderson]

On 22-Oct-1998, Zoltan Somogyi <zs at cs.mu.OZ.AU> wrote:
> 
> > The fact that you have to recompile the program in a grade that
> > supports stack traces in order to get a stack trace is an implementation
> > detail of the current implementation.  It is not necessarily
> > true of all implementations -- for example, if we ever develop a Java
> > backend, then it won't be true.  We shouldn't base the design of
> > the standard library on those kinds of things.
> 
> You are proposing instead that we base the design of the standard library
> on something we *might* do in the future?

The standard library should be designed to take into
account a wide range of possible implementations.

For *most* implementation techniques, stack backtraces are possible
without recompilation, so long as you don't completely strip the executable.
Even for our current implementation, trace information is possible
in many of the non-debugging grades.  The fact that the default grade
of our current implementation compiles via C using gcc non-local gotos and
doesn't use accurate GC makes it an exception, but the library design
should not give undue weight to that combination of circumstances.

The design of the standard library should avoid distributed fat: in
general, it shouldn't include features that have a cost (in this case
both a usability cost and also a small efficiency cost) that will be
incurred even by people who don't use the feature.

> > And adding an error message argument to all those predicates
> > (there are about 30 of them in the standard library)
> > would be a major change which is not an appropriate thing to do
> > while we have a feature freeze on.
> 
> I was not proposing doing it now.

So instead you propose leaving things inconsistent?
I think that is a bad idea.

Anyway, I think we have probably exhausted the debate on this issue --
perhaps a vote is in order?

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>  |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3        |     -- the last words of T. S. Garp.