F# Snippets

Domain model for the Tesco checkout implemented in F# using discriminated unions (in 20 lines of code) and console-based user interface for scanning products and calculating the total price.

When sprintf and String.concat is either too slow or not really what is needed, one can use System.Text.StringBuilder. This snippet makes working with StringBuilder much more convenient and the resulting code more succint.

The snippet implements a function "expand" that takes a quotation and performs two operations. It replaces all calls to methods marked with ReflectedDefinition with the body of the method and it simplifies all expressions that can be reduced in call-by-name style (let binding & application of...

This is a simple implementation of a monadic transaction builder for Clojure-style atoms. Based on original code by Nick Palladinos.

Andrew's Monotone Chain Convex Hull algorithm: given points in 2 dimensions, determine their convex hull by constructing the upper and lower hull.

This code illustrates Bayes' Theorem in action on the Let's Make a Deal problem, which several authors have used to illustrate Bayes' Theorem. (It's easy to search the internet for further explanation.) Run with the audit option to audit up to the first 100 games. Running without audit is faster...

Creating an asynchronous HTTP Server in F#.

JSON parsing with monads. See also "Expression parsing with monads" (http://fssnip.net/bi). Author URL: http://www.zbray.com

A single life annuity function in F# including supporting functions such as probability of survival, pure endowment and discounted interest rate calculation....

It's fairly straightforward in-place QuickSort implementation which uses ThreadPool for parallelization. Still slower than library function Array.sortInPlace, though.

Draws a Sierpinski triangle using WPF

One of the problems with using FileSystemWatcher to detect new files and process them is that it tells you when the file starts being created, not when it finishes. Use this little function to poll the file until it stops being written to.

Just toying around with making my F# code a little smaller with Haskell operators

Powerset function followed by with tiny sample.

A simple way to count the non-blank, non-comment lines in your code. (Doesn't use project files to identify source; just a wildcard. Doesn't support multi-line comments.)

DSL for functional style, HUnit-like testing with MbUnit.

A simple implementation for the sieve of Eratosthenes.

Remove duplicate elements of a list. Returns list with first instance of duplicate elements, without modification of order except subsequent duplicate elements are omitted.

Lab3

Demo F# unit test in VS11 beta. In VS 2010 unit testing requires a hack whereby you add a c# test project to your solution and add to that project a linked item to the DLL of the F# project with the test methods.