It's pretty simple:
julia> include("examples/enum.jl")
julia> @enum Foo BAR BAZ QUX
julia> Foo
Foo (constructor with 1 method)
julia> BAR
BAR
julia> BAZ
BAZ
julia> QUX
QUX
julia> isa(BAR,Foo)
true
julia> isa(BAZ,Foo)
true
Foo is a type and BAR BAZ and QUX are constants bound to instances of it.
On Thu, Dec 26, 2013 at 4:26 PM, Marcus Urban <[email protected]> wrote:
> I don't quite understand how to use the @enum macro in examples/enum.jl.
> Could someone give an example that would have a similar effect to the C++
>
> enum class Fruit { Apple, Banana};
> auto f = Fruit::Apple;
>
> Also, there is the @flags macro provided?
>
>
>
> On Thursday, December 26, 2013 3:12:33 PM UTC-6, Stefan Karpinski wrote:
>
>> That's a good approach if you're going to dispatch on the types, but if
>> they're just values, we really should have something more like an enum. At
>> this point, I'm thinking that @enum and @flags are good macros to have –
>> where the @enum macro just defaults to 0, 1, 2, etc. while @flags defaults
>> to 1, 2, 4, 8, etc. and defines bitwise operations on the flag values.
>>
>>
>> On Thu, Dec 26, 2013 at 8:13 AM, andrew cooke <[email protected]> wrote:
>>
>>> great, thanks. a concrete example is just what i needed. andrew
>>>
>>>
>>> On Thursday, 26 December 2013 00:06:07 UTC-3, Kevin Squire wrote:
>>>
>>>> The julia sort code might provide some guidance. It follows your last
>>>> proposal, having an abstract type Algorithm, and a number of concrete,
>>>> empty Algorithm subtypes (QuickSort, MergeSort, etc.), plus exactly one
>>>> global constant instance of each of these subtypes. So, as you suggested,
>>>> there is a little bit of setup overhead, but it allows you to use the
>>>> "value" of the global constants for dispatch.
>>>>
>>>> Kevin
>>>>
>>>>
>>>> On Wed, Dec 25, 2013 at 4:45 PM, andrew cooke <[email protected]>wrote:
>>>>
>>>>> I want to parametrize some code, so that it does one of three
>>>>> different things, depending on the "value" of a parameter. The parameter
>>>>> is purely symbolic - there's no corresponding numerical value.
>>>>>
>>>>> There's an enum.jl in examples and also some discussion of related
>>>>> ideas in issues. But this isn't (yet) in the language, and anyway it
>>>>> seems
>>>>> crude (these are symbols, not numbers).
>>>>>
>>>>> There's also the possibility of using an abstract type and then
>>>>> three concrete subtypes. That seems like too much work but, as far as I
>>>>> can tell, is the way to "do" algebraic types in Julia (see list.jl
>>>>> example).
>>>>>
>>>>> I guess I am overthinking this. But what is the right approach?
>>>>>
>>>>> Thanks, Andrew
>>>>>
>>>>
>>>>
>>
