[m-dev.] for review: rewrite of check_typeclass.m

[David Glen JEFFERY]

On 21-May-1998, Fergus Henderson <fjh at cs.mu.OZ.AU> wrote:
> On 20-May-1998, David Glen JEFFERY <dgj at cs.mu.OZ.AU> wrote:
> 
> > +:- pred check_instance_pred_procs(list(var), sym_name,
> > +        hlds_instance_defn, hlds_instance_defn, 
> > +        instance_method_info, instance_method_info).
> > +:- mode check_instance_pred_procs(in, in, in, out, in, out) is det.
> > +
> > +check_instance_pred_procs(ClassVars, MethodName, InstanceDefn0, InstanceDefn, 
> I don't understand why you still need this predicate,
> and many others in this module.  Is that just to support the optimization
> 
> > +                % As an optimisation, if the types and constraints
> > +                % are _exactly_ the same, there is no point introducing
> > +                % a predicate to call the instance method
> 
> ?  I think you could simplify the code dramatically
> if you delete this optimization -- is that correct?

That is quite correct.

> I think the right time to do this optimization is after LLDS optimization.
> Doing it here seems to add a lot of complexity for relatively little benefit.
> This will have significant maintenance costs.

I agree.

> 
> I suggest you check it in with the optimization in place,
> and then delete the optimization as a separate change.
> (That way, if we ever want to add it back, it'll be easy.)

Yes, that's a good idea.

> > +                % Perhaps we should include the pred arity in this mangled
> > +                % string?
> > +        % string__int_to_string(PredArity, PredArityString),
> > +        base_typeclass_info__make_instance_string(InstanceTypes, 
> > +                InstanceString),
>
> The pred name had better be unique, otherwise you may get
> link errors or C compiler errors. Thus yes, you should include the pred
> arity.  

But the arity gets included in the C name by llds_out. Am I right?

Is it OK to commit once I've changed these, or would you like to see another
diff?


love and cuddles,
dgj
-- 
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