Mitchell Wand | 11 Jul 16:04 1988

Danvy M 7/18, 1200


Olivier Danvy
DIKU - University of Copenhagen

Intenstions and Extensions in a Reflective Tower

Mon, 7/18, 1200 Noon
Room 107 Cullinane

This paper preents a model of the reflective tower based on the formal
semantics of its levels.  They are related extensionally by their mutual
interpretation and intensionally by reification and reflection.  The key
points obtained are:  a formal relation between the semantic domains of each
level; a formal identification of reification and reflection; the
visualisation of intensional snapshots of a tower of interpreters; a formal
justification and a generalization of Brown's meta-continuations; the
distinction between making continuations jumpy and pushy; the discovery of the
tail-reflection property; and a Scheme implementation of a properly
tail-reflective and single-threaded reflective tower.

Host:  M. Wand

Mitchell Wand | 11 Jul 16:12 1988

Consel T 7/19, 1200


Charles Consel
LITP-University of Paris 6/8

Tues, Jul 19, 1200 noon
107 Cullinane

New Insights into Partial Evaluation:  the SCHISM Experiment

This paper describes SCHISM: a self-applicable partial evaluator for a
first-order subset of Scheme.  SCHISM takes place in the framework of mixed
computation, and is situated along the line of the MIX project at the
University of Copenhagen.  The goal is automatically to generate compilers
>from interpreters by self-application and we have done this with an
extensible and directly executable first order subset of Scheme.

We use annotation for driving SCHISM to eliminate a call (unfold it) or to
keep it residual (specialize it).  These annotations are local to each
function rather than to each function call.  The usual pitfalls of such an
approach are avoided by associating a filter expression with each function.

Host: M. Wand

goguen | 15 Jul 03:25 1988

OBJ3 Release

Dear Colleagues:

Release 1.0 of OBJ3 is now available!

OBJ embodies basic design choices that are quite different from those of other
programming languages, even other functional programming languages.  OBJ3 is
the latest in a series of systems consisting of an interpreter and an
environment, and it has the following properties:

  1. OBJ3 is logical, in the sense that there is a logical system L such that

     * statements in OBJ3 programs are sentences in L,

     * the denotational semantics of an OBJ3 program P is an initial model
        of P, and

     * operational semantics is given by (efficient) deduction in L.

     This allows OBJ3 to be used as a theorem prover for L.  (In fact, the
     logical system L for OBJ3 is order sorted equational logic; see below.)

  2. OBJ3 has parameterized programming, which allows very flexible program
     structuring and reuse, giving the expressive power of higher order
     programming while retaining a first order logic, and supporting the
     following features:

     * objects to contain executable code, and theories to define properties;

     * parameterized modules, with theories to define interfaces;

(Continue reading)

Albert R. Meyer | 18 Jul 08:29 1988


Though the header of TYPES, LOGIC, and CONCURRENCY email has changed
slightly, htere has been no address change.

SCIENTIFIC mail to the email forums TYPES, LOGIC, and CONCURRENCY should
continue to be addressed to ``types@... '', ``logic <at> ...'',
``concurrency@...''.  ADMINISTRATIVE mail goes to
``types-request@...'', etc.

Previously email to these forums went direct to all subscribers.  It will
henceforth be filtered through the moderator of the forums.  The addresses
of the form ``NAME-list'' appearing in the ``To:'' field above are for the
moderator's use only, and will not work for other senders.

Yours truly,
Prof. Albert R. Meyer
MIT Lab. for Computer Science
Moderator, types@..., logic <at>,

Mitchell Wand | 19 Jul 21:23 1988

August Schedule

Here is the tentative schedule for August:

7/27 	no meeting
8/ 3	Eddie Wang	Jorring-Scherlis paper
8/10	no meeting
8/17	Bob Muller	Nielson&Nielson (start w/ Pragmatic Aspects... paper)
8/24	Bill White	Mosses papers  (tentative)

All meetings will be 100-300pm in 008 Cullinane.  See you there!