It is an old story about ....  false.

Long ago, back in 1989 I was working with mainframes and came across Turbo Prolog. What was good with this language - it had interesting manuals (in English). I did my pre-PhD exams (which never finished with PhD) and part of exams was English test.

So, I translated Turbo Prolog manuals into Russian. Was quite happy to do that because text of manuals was very interesting. And obvious.

I found a copy of Turbo Prolog compiler and started to play with it. Didn't find any problem to compile samples and they run straight away. One of the sample was about natural language processing and it was in English and I decided to modify and adopt it to Russian.

At that time I was familiar with everything you can call programming language (on mainframes) and thought that task is piece of cake. Especially when you have manuals translated from English to Russian.

This exercise finished with complete disaster. Program didn't work at all and regardless of my endless efforts. And it took me several weeks to understand why. And I did.

This looks very easy now, but for programmer with PL/1, C, Pascal background it took a while (in 1989) to understand why standard expression, such as

I = I + 1 is always

FALSE

If you are not convinced, simple question. Let say, you have variable I and it equals 5 (I = 5). Now, add 1 to this value. How much will be? Correct - 6. Is 5 = 6? Not. This is exactly what I didn't understand, that Prolog doesn't allow destructive assignment of the variables.

I made my program working. I wrote another program in Turbo Prolog and sent it to software contest (nobody runs such things now), program took 3rd place, I was awarded with Yamaha computer. Lot of things happened since that time. Turbo Prolog evolved to Visual Prolog, I live in Australia now.

EZY Prolog stands for EASY Prolog (it suppose to make logical programming easy). Why EZY? There is a chain of video rental in Australia, called Video EZY. Many things are easy in Australia and word EZY sounds very Australian.

It was not easy to write it, but I still keep hope, that it is easy to use.