The state of string interpolation

[Jonathan Marler]

On Friday, 7 December 2018 at 17:11:35 UTC, Atila Neves wrote:
> The only use I'd have for string interpolation is when 
> generating code (as a string) that spans multiple lines. Before 
> this thread I wasn't aware that scriptlike had string 
> interpolation. Now that I know it does, I don't know what I'd 
> need "proper" (i.e. language assisted) SI.
>
> Every language change is a cost, and therefore should justify 
> its inclusion. I personally don't think that it is in this case 
> just to make a niche use case slightly easier, and this coming 
> from someone from that niche! From now on it's:
>
> const code = mixin(interp!q{
>     // stuff that I used to write with many %s and it was hard 
> to match them up
> });

Your reasoning is sound but we differ in opinion here.  In my 
opinion the cost is low.  The implementation is very isolated.  
It's a simple change to the lexer and a new function call in 
parse stage that returns a tuple, that's it. You also say the 
usefullness is "niche" but I would disagree.  If it's implemented 
in the language then it could potentially replace the majority of 
calls to writeln/writefln.  It's more efficient than writefln and 
easier to read/maintain than writeln.  You yourself made a 
mistake in your own example because writeln is so clumsy to use.  
That's how I would use it anyway, I can't speak for everyone else 
but I think many people see this benefit as well.