Variable references in strings (Was: Structs implementing interfaces

[Don]

Ary Borenszweig wrote:
> bearophile wrote:
>> Ary Borenszweig:
>>> res ~= res ~= "\n\treturn 
>>> cast(${iface})cast(void*)&_iface_${iface}_vtbl;";
>>
>> Have you tried std.metastrings.Format!()? I use it quite often.
> 
> template Format(A...)
>     Formats constants into a string at compile time. Analogous to 
> std.string.format().
> 
>     Parameters:
>     A = tuple of *constants*, which can be strings, characters, or 
> integral values.
> 
> I want it in runtime. I basically want this:
> 
> foo = `Hello ${var}!`;
> 
> or
> 
> foo = `Hello $var!`;
> 
> to be the same as:
> 
> foo = `Hello ` ~ var ~ `!`;
> 
> You can see in this trivial example how readability is improved (and you 
> type less), and in a bigger example (like the one in this thread) it 
> should be better.

More than a year ago, I created a CTFE function dollar() to do that. 
It's a very simple. No language support is required.

foo = mixin(dollar("Hello $var!"));

We just need a way to get rid of the "mixin(" bit.