Hello & Why an LL _L_?

Patrick Premont premont@cs.toronto.edu
Wed, 25 Sep 1996 11:41:46 -0400

> Hello All,
> I'm interested in Tunes (I'm looking into it since several
> months). I'm 37 years old, married & father of 3 children, have a PhD
> in AI, and am interested by reflective systems. Professionnally I work
> as a computer scientist at CEA, but my interest in Tunes is only
> personal!

Your involvement would be very appreciated.

> But I don't understand why the Low Level Language (ie LLL) should be a
> language!
> I perfectly agree than there should be a low level procedural
> representation in Tunes. But in my opinion, it should not be defined
> as a language (e.g. parsed as a sequence of tokens, etc) but only as
> an internal representation, with a (reflective) API to access and
> modify it.

I've been questioning whether we needed a LLL at all. I was in favor
just having the HLL. And of course we need a low level representation.
So yes, I agree. But we may need to have a human readable
representation (does that make it a language according to your usage
of the term ?) for the LLR to make it easier for us to reason about
it and routines that have it as input or output.

> I think that the LLR should be somehow tree-like or DAG-like.
I don't think we should necessarily avoid cyclic data structures.
> But
> since it is a representation, not a language, some questions are
> simply irrelevant (eg scoping).

No scoping in exactly the form found in HLLs but I wouldn't be
surprised if we had some types of scoping at the LL. Scoping could
be used as a way of having compressed pointers. Pointers allow
us to talk about everything that is instantiated in memory somewhere.
But the cost is they must have log(mem_size) bits. In some cases
we may want to talk about something in a restricted context (a scope,
I'd say) and be thus be able to have a shorter representation.
Anyway, I'm being picky here.

> Names are not needed in the LLR
> (except for modularity), just use references (ie pointers) to the same
> object!

> N.B. Any opinions expressed here are solely mine, and not of my organization.
> N.B. Les opinions exprimees ici me sont personnelles et n engagent pas le CEA.

Ah, un autre qui parle aussi francais. :)

Maybe a live discussion on IRC would be interesting. I'm quite often
on EFNet as premont. If you or anyone else wants to talk with me about
tunes, just /msg me and we'll create a channel #tunes. A talk would work
also but in my experience having more than 2 people doesn't always work.
But talk may be the best way to reach me instantaneously, my talk server
is always up when I'm on the net (talk premont@rnode153.cs.utoronto.ca).

Quick intro to myself : I'm 23, finishing a MSc in AI, especially
interrested in tunes's formal aspects and its use of and application
to AI. Reflectivity also interests me a lot.

Patrick Premont