Opal

1. A DSP language.

["OPAL: A High Level Language and Environment for DSP boards

on PC", J.P. Schwartz et al, Proc ICASSP-89, 1989].

2. The language of the object-oriented database GemStone.

["Making Smalltalk a Database System", G. Copeland et al, Proc

SIGMOD'84, ACM 1984, pp.316- 325].

3. A simulation language with provision for stochasticvariables. An extension of Autostat.

["C-E-I-R OPAL", D. Pilling, Internal Report,

C.E.I.R. Ltd. (1963)].

4. A language for compiler testing said to be used internally

by DEC.

5. A functional programming language designed at the

Technische Universitaet Berlin as a testbed for the

development of functional programs. OPAL integrates

concepts from Algebraic Specification and Functional

Programming, which favour the (formal) development of (large)

production-quality software written in a purely functional

style.

The core of OPAL is a strongly typed, higher-order,

strict applicative language which belongs to the tradition

of Hope and ML. The algebraic flavour of OPAL is visible

in the syntactical appearance and in the preference of

parameterisation to polymorphism.

OPAL supports: information hiding - each language unit is

divided into an interface (signature) and an implementation

part; selective import; parameterised modules; free

constructor views on sorts, which allow pattern-based

function definitions despite quite different implementations;

full overloading of names; puristic scheme language with no

built-in data types (except Booleans and denotations).

OPAL and its predecessor OPAL-0 have been used for some time

at the Technische Universitaet Berlin in CS courses and for

research into optimising compilers for applicative languages.

The OPAL compiler itself is writte entirely in OPAL.

An overview is given in "OPAL: Design And Implementation of an

Algebraic Programming Language".

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(1995-02-16)