CT regex in AA at compile time

[Taylor Hillegeist]

On Tuesday, 7 January 2020 at 15:51:21 UTC, MoonlightSentinel 
wrote:
> On Tuesday, 7 January 2020 at 15:40:58 UTC, Taylor Hillegeist 
> wrote:
>> but I can't get it to work. it says its an Error: non-constant 
>> expression.
>>
>> I imagine this has to do with the ctRegex template or 
>> something. maybe there is a better way? Does anyone know?
>
> This issue is unrelated to ctRegex, AA literals are 
> non-constant expressions (probably due to their 
> implementation). You can work around this by using module 
> constructors or lazy initialisation inside of a function:
>
> static Regex!char[TokenType] Regexes;
>
> shared static this()
> {
>     Regexes = [
>         TokenType.Plus:   ctRegex!(`^ *\+`),
>         TokenType.Minus:  ctRegex!(`^ *\-`),
>         TokenType.LPer:   ctRegex!(`^ *\(`),
>         TokenType.RPer:   ctRegex!(`^ *\)`),
>         TokenType.Number: ctRegex!(`^ *[0-9]+(.[0-9]+)?`)
>     ];
> }

Thank you for bringing this to my attention.

also, the solution you used is very cool. I had no idea you could 
put shared static this()
just anywhere and have it execute just like it was in main! Does 
this work for dlls as well?