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Business applications for computers don't have to be boring things like accounts and stock control. Dlan, for the 16K or 48K Spectrum, is a simple programming language producing colourful, animated advertising displays with text in various sizes and typefaces.

With Dlan you design the displays with rectangular windows on the screen. The windows may be any size up to the full 24 by 32 screen dize and may overlap, and you can use any of nine decorative borders around them. As your text is printed it scrolls into the current window from the bottom and you can later scroll the windows independently in any direction.

There are eleven different typefaces in the 48K version, but only four in the 16K version, and the sizes vary from the normal Spectrum character size up to three times as high and double the width. You can use all the colours available on the Spectrum, and also the bright/dull and flashing/steady attributes.

The language consists of 31 single-character commands you enter into Basic REM lines, and you can use the Basic editor in the usual way to alter your program.

The cassette comes in a box with an insert that seems to have been designed with Dlan. The tape is recorded on both sides, with a demonstration program and the 16K and 48K version of Dlan on each side.

An eight-page booklet explains the commands and how to use Dlan, and gives hints on using the program for effective displays.

Dlan is simple to use and easy to set up, with the help of the instruction booklet. Its commands are executed one at a time in the order they appear in your program and you can build up your display a little at a time, testing it as you go.

The main problems you are likely to have are due to the lack of error messages. If you put invalid commands in your program Dlan will generally ignore what it does not understand and continue with the next command. For this reason it can be difficult to discover why the display is not coming out the way you want. For example, if you try to print characters that are three lines high in a window two lines high you will just get a blank window with nothing to tell you why.

A suggested use for Dlan is to produce fancy labels on the ZX Printer, but the Basic coy command only sends the top 22 lines to the printer. Dlan does not include a command to copy the full 24-line screen although this is easy to implement.

It is almost impossible to crash Dlan because it ignores incorrect commands. The only way I found to make it go wrong was to include a Basic line not beginning with REM, and even then the worst that happens is you drop into Basic with your program intact.

Although you may have problems because there are no error messages to tell you when you have done something wrong, Dlan is a simple language, easy to learn, but still very effective for producing animated text displays.

Features 4/5
Documentation 3/5
Performance 4/5
Usability 4/5
Reliability 3/5
Overall Value 4/5