Date: Mon, 1 Oct 2012 11:21:15 +0200
Subject: 1 October 2012, 11:00, L202: Dclare (Carel Bast, Wim Bast, Tom Brus)
From: Vadim Zaytsev
To: PEM
Cc: Carel Bast, Wim Bast

Dear environmentalists,

Coordinating the next PEM presentation this Friday will fall in the
trusty hands of Tijs, with yours truly still being at MoDELS.

The speakers have been specially invited by him, and will present
Dclare, a software language that abstracts away from sequentiality.


 Date: 5 October 2012
 Time: 11:00
 Room: L202 (Aquarium!)
 Speakers: Carel Bast, Wim Bast, Tom Brus
 Title: Towards a Programming Language That Really Abstracts Away from Time
 Abstract: see below

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              Towards a Programming Language
           that Really Abstracts away from Time

For some years now, the clock-speed of the CPU=92s can not be increase
significantly anymore. Parallelism is the only practically available
means to increase performance now. With currently available
programming languages however, the code-complexity is increased
dramatically for these architectures.

Even without considering parallelism software is becoming increasingly
complex. The impact of changes in large and complex software is almost
impossible to predict and comprehend.

The current mainstream programming languages are forcing us to express
functionality in terms of sequential processes. These processes are
not actually relevant to the functional problem domains. They are
mostly relevant for specifying the problem in the programming language
at hand, it is an over-specification. This burdens us with a
maintenance problem over time.

To solve these issues, we need a programming language that abstracts
away from time/sequential aspects. This language must be backed by an
execution environment that leverages parallelism in an implicit
manner. We present our language (Dclare) and our proposal for an
execution environment here.

The advantages will be that performance scales-up automatically with
the available processing power, in clock-speed and/or in CPUs. The
maintainability of our software will be improved by a higher level of
abstraction, and the absence of sequential process specification.

This new programming paradigm combines the advantages of
object-oriented and functional programming languages, without the
disadvantages of the non-functional aspects of ordinary OO and hybrid
languages. When we really need time related functionality, it must
(and can be) explicitly specified. But only then.

Of course this approach has some challenges. How do we efficiently
execute this language? Is this new paradigm easy to learn? Are we
humans capable of thinking about problems and solutions in a
declarative way?

In this talk we introduce the language "Dclare", the first really
declarative, functional OO language.

Dclare is a declarative language. It has an object oriented type
system, as in Java you define classes and fields, you can use
polymorphism, generics and lambda=92s. Methods are replaced by functions
and constraints. Functions can not have side effects. Constraints are
assertions with an enforcement strategy. When an assertion fails the
constraint defines how the assertion can be satisfied again.
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              http://event.cwi.nl/pem/calendar.html
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Yours,
     Vadim.