Euler Project Problem 14 in F# - An exercise in optimization The coding “coding-experiments” blog presents two alterative solutions to the “Euler Project Problem 14” (http://projecteuler.net/print.php?id=14): http://coding-experiments.blogspot.com/2008/03/projecteulernet-problem-14-csharp-vs.html   His F# solution is around 55 times slower in than the C# version, the implication being that while F# is elegant, it’s also slow. My problem with this conjecture is that that the implementation of the F# version is considerably different to the implementation of the C# version. So lets have a look at the two different version, first the F#:     let seq_length n =         n |>         Seq.unfold(fun x ->                     match x...

One thing functional languages excel at is abstraction of control flow. Although you may not be familiar with the term, you’re probably already familiar with the concept. Programmers coming from an OO background are generally familiar with implementation polymorphism (overriding a method in a base class) and dependency injection (using an interface or base class to call methods an object, dynamically generated or otherwise); these are both forms of abstraction of control flow. They both allow the programmer to implicitly choose a different method to execute as long as that method conforms to some predefined signature. Let’s quickly remind ourselves...