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Today, thanks to user Lucero on StackOverflow, I learned about .NET’s “Balancing Groups” Regex feature. Basically, any time you use a named capturing group, it actually pushes the capture onto a named stack. You can then pop this stack by using the same capturing group prefixed with a hyphen, like (?< -stackToPop>). Of course, anyone [...]

Here’s a little example of statically-sized stacks in C#. They’re implemented with a linked-list as the backing store: using System;   namespace ConsoleApplication { public static class MainClass { // Example:   public static void Main(string[] args) { var stack = Stack.New<int>(); // real type Stack<Z,int>   var s1 = stack.Push(1).Push(2).Push(3); // real type Stack<S<S<S<Z>>>> [...]

So, I thought it would be a fun idea for my first ever Lisp/Scheme program to implement Alan Turing’s original a-machines from his paper, On Computable Numbers, with an Application to the Entscheidungsproblem (paper available to public). Fun? Oh, I hadn’t any idea… Preamble; choice of implementation I decided to go with the latest and [...]

While Googling my way through the interwebs, I came across the 2008 Western Australian Certificate of Education sample examination for Stage 2 Biological Sciences. It contains this diagram: If you’re wondering, the entire hierarchy is drawn from Umberto Eco‘s novel Baudolino.