Tentative Language Design Summary version 0.92 available

[pdmosses@brics.dk]

Now that the vacation period is over (for most of us), we should try
to settle the remaining points concerning the Tentative Design
Proposal as soon as possible.  I've just finished installing a new
version of the summary, with an accompanying study note; see below.
I'll be sending a summary of comments on the previous version in a
subsequent message.

Looking forward to your contributions!

Peter

----   --------------------------------------------
\  /  | Peter D Mosses         <pdmosses@brics.dk> |
CoFI  | Common Framework Initiative  - Coordinator |
/  \  | WWW URL: http://www.brics.dk/Projects/CoFI |
----   --------------------------------------------

News

26 August 1996: 
       [Tentative Design Proposal] A new version of the Language
       Summary, version 0.92, is now available. (See below.)

              Deadline for comments: 9 September 1996! 

26 August 1996: 
       [Study Notes] A new study note on subsorting [MC+PDM-1] has
       been installed.

-------------------------------------  

The COFI Algebraic Common Language(1)
Tentative Design: Language Summary

     CoFI, The Common Framework Initiative for Algebraic Specification

     DRAFT, Version 0.92 (26 August 1996)

     This document is available for printing in Postscript and DVI
     formats at URL:
     ftp://ftp.brics.dk/pub/BRICS/Projects/CoFI/DesignProposals/Summary.ps.Z
     ftp://ftp.brics.dk/pub/BRICS/Projects/CoFI/DesignProposals/Summary.dvi

Abstract

     This draft summary of the tentative design of the COFI Algebraic
     Common Language is based on the agreement reached at the working
     meeting of the Language Design Task Group (Munich, 5-7 July 1996),
     and on further discussions with several of the participants the
     following week (while attending a Dagstuhl seminar). This version
     incorporates comments received up to 22 August, as well as the
     results of further collaborative study of how to accommodate
     subsorts.

     A list of the main changes from the previous version is included,
     as well as a list of just which points of the design are currently
     regarded as requiring further discussion and decisions within the
     Language Design Task Group.

     This version is still very much a draft for discussion, and has
     not been approved by the COFI Language Design Task Group.

          The deadline for comments is: 9 September 1996!

     The language summarized here--to be referred to as X until a
     proper name has been chosen--is central to COFI: it is a
     reasonably expressive algebraic specification language from which
     simple COFI languages (e.g., for interfacing with existing tools)
     are to be obtained by restriction, and which is to be incorporated
     in advanced COFI languages (e.g., for specifying reactive
     systems). X strikes a balance between simplicity and
     expressiveness. The main features of its design are as follows:

     Basic specifications in X denote classes of many-sorted partial
     first-order structures, i.e., algebras where the functions are
     first-order, partial and/or total, and where first-order
     predicates are allowed. Axioms are full first-order formulae;
     definedness assertions and both strong and existential equations
     are provided. Sort embeddings are provided as injections. Sort
     generation constraints can be specified. Type definition schemas
     are provided for concise specification of enumerations, records,
     and sort unions.

     Structured specifications allow translation, union, and extension
     of specifications. Extensions may be required to be persistent
     and/or freely-generated; initial constraints are a special case. A
     simple form of parametrized specifications is provided, together
     with (possibly partial) instantiation involving parameter-fitting
     translations.

     Finally, so-called decompositional specifications express that the
     system being specified is composed from some independent parts by
     another part, the latter depending on them via interfaces.

     For further details of the original requirements and functionality
     for the COFI Common Language for Algebraic Specification, see the
     Working Documents "Meta-Requirements" and "Meta-Design",
     accessible via the COFI Home Page.

Contents:

   * About this document
        o Purpose
        o Structure
        o Comments
        o Contributors
        o Versions
        o Related documents
   * Main Issues for Discussion
   * Basic Concepts
        o Signatures
        o Models
        o Sentences
        o Satisfaction
        o Proof System
        o Constraints
   * Basic Constructs
        o Declarations of Symbols
        o Axioms
        o Sort Generation
        o Type Definition Schema
   * Structuring Concepts
   * Structuring Constructs
        o Specification Libraries
        o Specification Expressions
        o Parametrized Specifications
   * Decompositional Concepts
   * Decompositional Constructs
   * Footnotes
   * Appendix A: Abstract Syntax
        o Basic Specifications
        o Structured Specifications
        o Decompositional Specifications
   * Index

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(1) 
       Name not yet decided. Suggestions: Alcol? CoFI-Ground? Black CoFI?