> For the complete documentation index, see [llms.txt](https://smllang.gitbook.io/home/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://smllang.gitbook.io/home/basics/enum-specialization.md).

# Enum Specialization

You are special, like the enum types

Each branch or instance of the enum can also be used to represent the specific type. This allows us to write straight forward functions which expect a specific value of the enum. This approach eliminates the over-use of the match expression as a way to decide datatypes inside a function. 

{% code lineNumbers="true" %}

```rust
enum Presidents = Mandela | Obama | Putin | JunPing
```

{% endcode %}

We can write the specialization functions like this. 

{% code lineNumbers="true" %}

```rust
fn zar(prez: Presidents.Mandela): String => prez + " Was the president of South Africa"

```

{% endcode %}

This is how to use them. 

{% code lineNumbers="true" %}

```sml
fn main(): Unit => {
    val myprez = Presidents.Mandela
    println(zar(myprez)) (* compiles successfully *)
    println(rus(myprez)) (* fails *)
}
```

{% endcode %}