Proof of concept: automatic extraction of gettext-style translation strings

[Adam D. Ruppe]

On Thursday, 2 April 2020 at 15:53:58 UTC, Sönke Ludwig wrote:
> BTW, I never got around to commenting on the string 
> interpolation topic, but the inability to translate i"" strings 
> was my biggest practical concern. Never really understood the 
> reluctance against lowering to a template instantiation, though.

Yeah, I don't wanna derail too much but my version here:
https://github.com/dlang/DIPs/pull/186

could be used. Here, I kept the part I cut out of the file - I 
just wan't happy with the details all being right, but the thrust 
of it has:

-----

##### Internationalization

The string must be processed in whole, with as much context as 
possible for the translator to do a good job. If the string was
broken up into a tuple, it would be very difficult for a 
translator to make sense of it. With `_d_interpolated_string`, 
however,
the static components are clearly separated from, while still 
being clearly associated with, their companion runtime arguments, 
and are indeed available at compile time.

Moreover, it may be necessary to reorder words and act on factors 
like plurality. With the templated version together with a helper 
function (e.g. `translate(i"I have $count apples")` you can get a 
compile-time list of strings needing translation and write 
runtime functions to handle localization details as required for 
individual strings.

```
string translate(d_interpolated_string!("I have ", spec(null), " 
apples") spec, int count) {
    if(count == 1)
         return "I have 1 apple";
    else
         return format(spec.ToFormatString!"%d", count);
}
```

------


I never finished that section, I just wasn't happy with my 
examples and arguments, but it is one of the things on my mind. 
You could do complicated logic in D itself all verified at 
compile time.

Or just pass to a runtime thing like gnu gettext possibly with 
helper templates.


D has a LOT of potential in this area that we have barely even 
scratched the surface of.