Danish APL Group at Copenhagen

Transcribed from the printed issue; not yet reviewed. Read it in the PDF of the issue, page 74

The Danish APL Special Interest Group under the Danish Data Association hosts a series of late afternoon meetings each season. The content of the meeting varies and includes presentations of new releases of APL interpreters, new add-on products to APL, and Case Studies from APL-users. The attendance varies too, from 20 to 60 APLers.

On November 27th we had invited Bo Grave from the Danish Railroads and Adrian Smith from Causeway.

Bo Grave spoke about his recent work on controlling signals for railroads. His work is based on BeoLogic, a constraint solving system based on binary nested arrays developed by Gert Møller for Bang and Olufsen. If you would like to read more about the background to this, Bo’s APL96 paper is available on the web at www.demon.co.uk/apl385/apl96

The system allows the user to define all valid solutions to a given set of input. Having specified all constraints the model is reduced to a dense binary array containing the full operational information to control a complicated system, in Bo’s case the railroad signals. One of the big advantages of the system is that since all possible combinations are generated and taken into account the model can be checked for consistency, making sure that any set of input has one and only one valid response from the controlling system. Other uses of the system are not surprisingly the Beolink system by which all musical outlets in your house can be coordinated via the same remote control; also power supply systems can be modelled using Beologic.

Adrian Smith started out by showing the audience some examples of the work Causeway has been doing for SAP using the design tool Causeway. After this introduction a short guided tour of the facilities of Causeway left the audience with the impression that certainly object-oriented style applications were no longer beyond their capabilities as application developers. Causeway is currently shareware being distributed with Dyalog APL but will soon appear in a fully documented Pro version.

The next presentations were the Pro versions of NewLeaf and Rain, which Dyalog APL users have had the opportunity to experiment with for a while. Now with both products being fully documented and available for both APL+Win and Dyalog APL we should expect to see some flashy output generated from APL applications.

Both utility products are extremely easy to use and generate publication quality output.

APL-users will particularly appreciate the ability of Rain to handle non equidistant axis divisions, a very useful facility when dealing with time series and an area which has not been dealt with properly by the standard graphics DLLs, VBXs and the like.

NewLeaf allows you to lay out, format and design compound reports containing bodytext, tables generated from APL variables, and graphics from Rain in a very flexible and dynamic way. NewLeaf also comes with a layout designer, a facility the audience expressed interest in having available for Rain as well.

At the very end Adrian was asked whether he had a utility for generating Windows help files in an easy way. And you guessed right — of course he had. Having it demonstrated the audience’s response was a definite make this a product too.

It is always a joy to see ingenious uses of APL and to watch the growing success of commercial APL applications. It is also reassuring to see how tools for Windows APL development now become available as products just like they did for the mainframe environment. It strongly confirms my belief that APL is indeed very much alive and faces the future as a capable tool for implementing simple solutions to complex problems.