A library which enables more powerful pattern matching
than is currently available in the C#'s switch statement/expression.
This repository is deprecated. Version 2+ can be found here: https://github.com/TolikPylypchuk/Matchmaker
Install-Package CSharpStuff.PatternMatching -Version 1.2.0
This is what the simplest match expression looks like:
using static PatternMatching.Pattern;
// ...
string result =
Match.Create<int, string>()
.Case(EqualTo(1), _ => "one")
.Case(EqualTo(2), _ => "two")
.Case(EqualTo(3), _ => "three")
.Case(EqualTo(4), _ => "four")
.Case(Any<int>(), i => i.ToString())
.ExecuteOn(5);
EqualTo is a predefined pattern.
This is what an equivalent switch statement looks like:
string result;
int i = 5;
switch (i)
{
case 1:
result = "one";
break;
case 2:
result = "two";
break;
case 3:
result = "three";
break;
case 4:
result = "four";
break;
default:
result = i.ToString();
break;
}
While this example doesn't show the full power of pattern matching, there are a few things to note here:
-
The match expression yields a result. We don't have to assign the result explicitly in each case.
-
The input of the match expression is specified after all the cases. This allows us to save the match expression in an object, and use it multiple times on different input values.
-
The default case is a pattern, just like any other. It's called
Anyand is always matched successfully. -
Like in
switchthe patterns are tried out sequentially. This means that theAnypattern should always come last.
The documentation can be found here:
- Version 1.2.0: https://patternmatching.tolik.io/v1.2.0
- Version 1.1.0: https://patternmatching.tolik.io/v1.1.0
- Version 1.0.0: https://patternmatching.tolik.io/v1.0.0