Compile-time associative array

[Steven Schveighoffer]

On 3/20/19 4:11 AM, boolangery wrote:
> On Tuesday, 19 March 2019 at 23:41:58 UTC, Steven Schveighoffer wrote:
>> On 3/19/19 7:22 PM, Bastiaan Veelo wrote:
>>
>>> Beware that a CT AA stores its elements in a different order than a 
>>> RT AA, which you would notice in a foreach, for example.
>>
>> Yes, this is the issue -- the runtime AA depends on druntime, which is 
>> not available to the compiler. The compiler has its own AA 
>> implementation that it uses for CTFE.
>>
>> The internals will not be the same, which is why you can't construct 
>> one at compile-time and use it at runtime (the enum just recreates it 
>> at runtime when used).
>>
>> -Steve
> 
> Got it ! Thank you, so I need to write:
> 
> enum string[string] CtfeFoo = ["foo" : "bar"];
> static immutable string[string] Foo;
> 
> static this()
> {
>      Foo = CtfeFoo;
> }
> 
> string ctfeableFunction()
> {
>      if (__ctfe)
>          return CtfeFoo["foo"];
>      else
>          return Foo["foo"];
> }

Ugh, yes, that's required.

Probably can be abstracted in a template.

-Steve