` that I get a list of colors to choose from
What you want is basically a namespace, so, in Julia, a `Module`. I usually simply write a small inline module when I want an enumeration type:
```julia
"""
`Actions.Action` is an enumeration type. The allowed values are:
1. `Actions.add` for adding
2. `Actions.move` for moving
3. `Actions.finish` for finishing
"""
module Actions
struct UnknownActionException <: Exception
unrecognized_action::Int
end
struct Action
a::Int
function Action(a::Int)
(0 ≤ a ≤ 2) || throw(UnknownActionException(a))
new(a)
end
end
const add = Action(0)
const move = Action(1)
const finish = Action(2)
const actions = (add, move, finish)
const compile_time_test = (
() ->
if allunique(actions)
nothing
else
error("inconsistent enumeration definition")
end
)()
end
```
Maybe it would make more sense to just use `EnumX`, though.
---
### Author:  [@nsajko](https://discourse.julialang.org/u/nsajko)
#### Post date: [June 24, 2023, 5:41pm UTC](https://discourse.julialang.org/t/more-comfortable-enum/100779/4 "2023-06-24T17:41:08Z")
> [@DrChainsaw](#):
>
> I have also just added a module with some non-instantiable types for user-facing enums where I want users to discover the types through tab, for example (untested as Im typing on phone):
>
> ```julia
> module Color
> abstract type red end
> abstract type green end
> abstract type blue end
> end
>
> ```
>
> Not sure if there are disadvantages with the latter though.
Could you give more context on how do you use this? I suspect that using singleton `struct`s would be more idiomatic than using `abstract type`.
---
### Author:  [@DrChainsaw](https://discourse.julialang.org/u/DrChainsaw)
#### Post date: [June 24, 2023, 8:08pm UTC](https://discourse.julialang.org/t/more-comfortable-enum/100779/5 "2023-06-24T20:08:48Z")
It was just for a very simple case when I wanted some labels for the user input, the kind where it is common to see symbols. I wanted them to be tabbable and I wanted to make sure everything discoverable through tab was a valid input.
---
### Author:  [@ufechner7](https://discourse.julialang.org/u/ufechner7)
#### Post date: [June 25, 2023, 6:33am UTC](https://discourse.julialang.org/t/more-comfortable-enum/100779/6 "2023-06-25T06:33:38Z")
EnumX looks like a solution (TAB completion works), but then I always need to prefix the enum values with the enum type… Not sure if I want this.
I have a function `run_tests(test...)` where test is a member of the enum TestCases. See:
```julia
function help()
println("Run one or more of the following tests:\n")
for test in instances(TestCases)
println("run_tests($(String(Symbol(test))))")
end
end
```
Not sure yet if I change anything, both enum and enumx have their advantages…
---
### Author:  [@hendri54](https://discourse.julialang.org/u/hendri54)
#### Post date: [June 25, 2023, 12:58pm UTC](https://discourse.julialang.org/t/more-comfortable-enum/100779/7 "2023-06-25T12:58:47Z")
> [@ufechner7](#):
>
> but then I always need to prefix the enum values with the enum type… Not sure if I want this.
You can always define
```julia
julia> @enumx Fruit Apple Orange
julia> const Apple = Fruit.Apple
```
(which sort of defeats the purpose of the EnumX package, though).
---
### Author:  [@Dan](https://discourse.julialang.org/u/Dan)
#### Post date: [June 25, 2023, 1:25pm UTC](https://discourse.julialang.org/t/more-comfortable-enum/100779/8 "2023-06-25T13:25:38Z")
Isn’t exactly this sort of problem addressed with module `import` and `using`?
I would expect an `Enum` declaration to `export` values if it wishes, and then these would be in the namespace if the `Enum` is `using`-ed, and if I care about cluterring the namespace, then `import` can be used.
Can some sort of syntax/macro achieve this?
---
### Author:  [@Henrique\_Becker](https://discourse.julialang.org/u/Henrique_Becker)
#### Post date: [June 25, 2023, 6:15pm UTC](https://discourse.julialang.org/t/more-comfortable-enum/100779/9 "2023-06-25T18:15:56Z")
…
This is exactly what macro [`@enumx`](https://juliapackages.com/p/enumx) does. It do a simple Enum declaration inside a Module so it is immediately scoped.