Blog

Failing a Generator on First Failure

There are occasions when working with some generative predicate where you don't know when you need to quit the generation until some condition fails. Trouble is, you'll fail with no chance of future success but you're now lost in an infinite loop as the generator keeps on trying. In this post we'll work through a blog pagination example and show how to use a dirty little trick with a cut.

Emacs X Window Manager On Raspberry Pi

Emacs was a great operating system, it just lacked a good text editor like Vim. Well times have moved on, now you can use Emacs as your window manager with Vim text editing. Let's try it out on a Raspberry Pi.

Basic Idea Of Recursion

Want to do something a bunch of times in Prolog? Recursion is how we do it. In this post we'll look at the most basic ideas of recursion and talk through a couple of examples.

"Hello, Tau Prolog!"

Imagine an internet where you didn't need to write JavaScript… Imagine an internet where you could write Prolog… Imagine no more, write Tau Prolog!

Predicates vs Functions

People from other languages often get a little confused with these predicate things, especially as their syntax looks similar to functions in other languages. In this post we contrast predicates and functions and demonstrate the advantage of using predicates over functions.

Prolog Partial Predicates

Did you know you can call partial predicates with arguments added later on? This is how many of the higher order predicates like `maplist` work. But you can take advantage of this too! Let's take a look at `call`.

Prolog: Forwards and Backwards

A key idiom in Prolog is the idea that it runs both forwards and backwards. If you've never programmed in Prolog before, this can be mind-blowing! You can write one "function" and get many different uses out of it. In this post we'll take a look at what this means as a teaser that might tempt you into giving Prolog a go.

Homoiconic Prolog: Explain yourself!

Prolog is rather popular for Expert Systems. Why? Well because it's homoiconic and because we have DCG's, we can reify a query to make it explain itself. That's a lot of jargon, in this post we'll break it down and make some explanations.

Difference Lists Explored

In Prolog, Difference Lists are a very powerful and useful tool. They're also difficult to understand and can result in difficult to read code. In this post we'll address both of these issues.

Functional Prolog: Map, Filter and Reduce

Prolog programs have both logical and procedural meanings. In this post we'll take a look at procedural ideas more commonly associated with functional programming than Prolog, namely: map, filter and reduce (foldl and foldr). We'll code them and then query them.