[m-users.] problem with unique modes

[Matthias Güdemann]

Hi Mark,

> Please read Julien's remarks made at the time. The inst
> `bound(mk_pair(unique, ground))' does not make sense, and ought to be
> rejected before mode analysis starts.

I had read it and got the impression that this would not be very
difficult and completely separate from nested unique modes.

> Given that nested unique modes are not supported at all, it would
> hardly be a high priority to check for unique insts wrongly occurring
> inside bound insts. It isn't something that users will stumble upon
> unsuspectingly, in my view.

definitely! That's why I wrote "abuse".

>> Is this topic still worked on?

> You mean are people still abusing insts in an attempt to prove that
> Mercury doesn't work? You tell me. ;-)

No, I was referring to nested unique modes. But this was probably not
very clear from my mail.

Currently, I do not know much about the internals of the compiler and
nothing about the mode analysis.

I'd like to understand the problem with nested unique modes. When
reading through the archives, this was a recurring topic and Ralph
Becket mentioned that

 "We do have a workable analysis sketched out, but just don't have the
  resources to fix this particular problem at the moment."

Is this information available somewhere? 

Matthias