DIP 1027---String Interpolation---Community Review Round 1

[Patrick Schluter]

On Monday, 16 December 2019 at 11:08:00 UTC, Patrick Schluter 
wrote:
> On Monday, 16 December 2019 at 10:48:51 UTC, aliak wrote:
>
>> Resolving interpolation at compile time is imho incompatible
> with handling them as regular strings.

Maybe I'm wrong here, I haven't thought it through, but in first 
approach I think that's an essential point. As the string 
contains code, if evaluated at CT, the string must be split 
somehow in literal parts and code parts. Allowing the i-string to 
be handled as regular string implies that the splitting happens 
sometime between when it is declared and after it is used, which 
can happen after runtime.

import fn;

int b = 20;

string inter = i"$(a+b)";

foreach(a; 1..10)
   fn(inter);

---
module fn;

void fn(string s)
{
   writefln(s);
}

How would that work?

In python or javascript there's no issue, a is a runtime symbol.

>
> The question is then do we want CT or RT interpolated strings. 
> RT interpolated strings can still be provided by a library.