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Although I enjoy learning and exploring new computer languages, when I saw the Sinclair Micro-Prolog package, I was a little worried to say the least at the size of the manual and its complexity.

Still thinking that I had let myself in for a pretty stiff little number, I dived into the introductory manual whch is much thinner and aimed toward your average Speccy user. After three pages of how to switch your computer on and how to load a program, I finally found out about the "SIMPLE" language. SIMPLE is a program which changes the way you use Micro-Prolog so that it is not too confusing at first. I was quite impressed, I managed to follow what the manual was telling me without becoming hopelessly lost.

Prolog itself is a logically-structured language; that is, it is nowhere near as messy as Basic, but then it is not as easy to grasp as Basic. Consider the Micro-Prolog line:

which (x : x larger London)

Taking this line step by step, first we have the command 'which', This is asking Micro-Prolog a question. The question is contained within the brackets and is in the form 'output format:argument'. In the example above, I am dealing with cities and am looking for all the cities 'larger' than London. The word 'larger' in itself doesn't mean anything to Micro-Prolog, what it is doing is just looking through its database and finding any placed were a city has been specified as larger than London.

The large green manual which accompanied the cassette was far beyond me. I found I could use the program quite well enough just by following the small booklet.

The main use of Micro-Prolog is obviously 'do-it-yourself' database. Tailoring the filing system to your own requirements is very simple. Once you have a knowledge of Micro-Prolog, you can create a database far better than any commercially available - because you know exactly what you want from the system. Table 1 shows the commands available and their syntax.

The loading and saving operations are similar to that of the BBC in that they load in blocks and it is very slow. It is quite reliable though, and the programs you write are not likely to be too large anyway.

Micro-Prolog was written by Logic Programming Associates Ltd, and is available from most high street stores under the Sinclair label priced at £24.95.

Table 1. Commands and Syntax