Enumerations

If are you are used to C, you will be well used to enumerations, for example:

enum myEnum {start = 4, next, nextone, lastone=999};  

This creates an enum type that auto-fills next and nextone to be start + 1 and start + 2 respectively. If the first named parameter has nothing to give an initial value to, it is given the value 0 with everything after it being one larger than the last. They are accessed as myEnum.nextone.

An enum type in Rust has a very similar structure to a struct type, as shown in the following code:

enum MyEnum 
{ 
     TupleType(f32, i8, &str), 
     StructType { varone: i32, vartwo: f64 }, 
     NewTypeTuple(i32), 
     SomeVarName 
} 

As with C though, an enum is a single type, but the value of the enum can match any of its members.

Accessing enumeration members

Given the possibility of the contents of a Rust enum, you may be thinking that accessing one of the members within the enumeration may not be the simplest of tasks. Thankfully, it is, as an enum variable...