addle 0.1.0 - argument-dependent lookup for UFCS functions

[Atwork]

On Sunday, 21 June 2020 at 00:06:12 UTC, Paul Backus wrote:
> Are you tired of D's sane, straightforward scoping rules? 
> Itching for a taste of that old-fashioned C++ madness? Well, 
> itch no more: addle is here to help.
>
> addle is a tiny library that implements C++-style 
> argument-dependent lookup (ADL) for D, on an opt-in basis. It 
> lets you extend existing types with UFCS methods, and share 
> those methods seamlessly with code in other modules--no 
> `import` required!
>
> Here's a brief example:
>
>     import addle;
>     import std.range;
>
>     // Import a type from another module
>     import mylib: MyStruct;
>
>     // Define range primitives for MyStruct
>     bool empty(MyStruct a) { return false; }
>     string front(MyStruct a) { return "ok"; }
>     void popFront(MyStruct a) {}
>
>     // MyStruct isn't considered an input range, because
>     // std.range can't see our UFCS methods.
>     static assert(isInputRange!MyStruct == false);
>
>     // ...but extending it makes those methods visible.
>     static assert(isInputRange!(Extended!MyStruct));
>
>     void main()
>     {
>         import std.range: take, only;
>         import std.algorithm: equal;
>
>         MyStruct myStruct;
>
>         // Now we can use all of the standard range algorithms
>         assert(
>             myStruct.extended
>             .take(3)
>             .equal(only("ok", "ok", "ok"))
>         );
>     }
>
> Now available on Dub, by "popular demand"!
>
> Links:
>   - Documentation: https://addle.dpldocs.info/addle.html
>   - Dub: https://code.dlang.org/packages/addle
>   - Github: https://github.com/pbackus/addle

That's pretty neat.

I wonder if something like that could have been used when 
checking types in phobos? Probably wouldn't be implemented as I 
can imagine a performance impact during compilation tho.