PatternMatching

A simple .NET library with extension methods to allow you to do pattern matching with fluent syntax instead of doing a switch or a dictionary.

Usage

Simply make a reference to the assembly in your project, then add the line

using PatternMatching;

A few examples are:

int a = 5;
a.When(x => x == 5).Do(_ => Console.WriteLine("I am five!"));

That example should print "I am five!" to the standard output.

You can even chain With/Do operations together!

int a = 5;
a.When(x => x == 5).Do(_ => Console.WriteLine("I am five!"))
 .When(x => x != 5).Do(_ => Console.WriteLine("I am not five!"))
 .When(x => x >= 5).Do(x => Console.WriteLine("{0} is greater than or equal to five!", x))
 .When(x => x <  5).Do(x => Console.WriteLine("{0} is less than five!", x));

That example should print only the lines "I am five!" and "5 is greater than or equal to five!" to the standard output.

Finally, there are two operations that can be executed after existing ones:

• the Otherwise operation, which is the default fallthrough in case nothing else has been satisfied
• the Then operation, which gives you a continuation on what to do after all the other conditions have been satisfied.

We'll demonstrate these two with the classical FizzBuzz problem.

foreach (var i in Enumerable.Range(1, 100))
    i.When(x => x % 3 == 0).Do(_ => Console.Write("Fizz"))
     .When(x => x % 5 == 0).Do(_ => Console.Write("Buzz"))
     .Then(() => Console.WriteLine())
     .Otherwise(x => Console.WriteLine));

License

PatternMatching is licensed under the BSD License.