Giving Your Data Some Higher Order Muscle With C#

Today a colleague and I were going through some code.  I have recently been trying to impart to him the power and beauty in the functional programing paradigm in C#.  Today, the opportunity to demonstrate it presented itself as I was showing him how to use extension methods to extend Entities and ValueObjects with a suite-to-purpose functional API.  As we began the code, I realized that what I really wanted to show him was the concept with no additional fluff.  First, the extension method part.

Here’s what I came up with:

public static class IntExtensions
    public static void Times(this int count, Action<int> action)
        for (var i = 0; i < count; i++)

This small extension to the builtin int type, gives us a convenient and expressive functional API, driven directly from Int32 typed variables themselves.  Now, we can use it as follows.

public void SampleRepository_Can_Create_New()
     10.Times(i =>
          var sample = TestObjects.BuildSample();

     var samples = SampleRepository.GetAll();
     samples.Count().Times(i => Debug.WriteLine("your index is " + i));

     Assert.IsTrue(samples.Count() == 10, "Should have 10 samples");

Rubyists recognize this API as its built into the language. Its simple stepwise iteration driven directly off numeric types. In C# we can use extension methods to shim this behavior into our scalers. APIs that read like 5.Times(doSomething); read like English.  This makes our code  more comprehensible by everyone, and that ladies and gentlemen is worth its weight in Gold Pressed Latinum

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