String interpolation, after a healthy debate on discord
schveiguy at gmail.com
Tue Dec 14 15:49:52 UTC 2021
On 12/14/21 6:15 AM, WebFreak001 wrote:
> On Tuesday, 14 December 2021 at 11:02:58 UTC, Ogi wrote:
>> On Tuesday, 14 December 2021 at 09:35:27 UTC, WebFreak001 wrote:
>>> no this proposal does not suggest moving any functionality into the
>>> compiler. It suggests to add the istrings (tuples with header) as
>>> described in the YAIDIP and have special function calling syntax
>>> (`functionName"istring contents"`) that will call any function, that
>>> accepts an istring as only argument.
>> I was referring to YAIDIP. According to it, istring should be allowed
>> in `mixin`, `pragma(msg)` and `assert` (missed this one). This
>> requires reimplementing `text` in the compiler.
pramga(msg) and mixin do not need implementations of `std.conv.text`.
`pragma(msg, "x = ", x);` already works, just need it to ignore the header.
`mixin("int y = ", x + 5, ";")` already works, just need it to ignore
assert would need some implementation of runtime output. But it's
already in the library with `-checkaction=context`. It just needs to be
> ah right you mean for the built-in istring usage in the compiler it
> needs to be implemented.
> I don't think it's such a big problem though, as the phobos
> implementation would also just be: (a little simplified)
> auto text(istring...)(istring s) if (isIString!istring)
> return text(s[1 .. $]); // removes special __header, just
> concatenate rest
The DIP is designed specifically to work with `text` as-is. You don't
need a special overload (because the header has a `toString` that
returns ""). This was inherited from our DIP.
As for the specialized call syntax, I don't think we need it.
As for implementing some `text`-like thing in druntime, we already have
some of it, I think it would be reasonable to include something in
object.d that does a straightforward conversion when you don't want to
use std.format. The only complex one is floating point. This all can be
done AFTER the DIP is accepted anyway.
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