Interpolation struct names and location

[Paul Backus]

On Wednesday, 14 February 2024 at 05:30:47 UTC, Steven 
Schveighoffer wrote:
> However, [these 
> names](https://github.com/dlang/dmd/blob/98443676dcfa32f7234ebab6ca9f925e1d3cd736/druntime/src/core/interpolation.d#L102) are rather verbose. And every function that accepts these sequences is going to be mangled with some pretty long names.
>
> I propose we discuss both for where these types should live and 
> what they should be called. I personally think we might want to 
> move these things to object.d (yes, I know object.d is big, but 
> these are not big or complex types), and rename them something 
> more succinct.

I think putting them in `core.interpolation` instead of 
`object.d` is fine. Having to `import core.interpolation` when 
you write a function that takes an interpolation sequence is no 
worse than having to `import core.vararg` when you write a 
variadic function.

Normally, my suggestion would be to not repeat the module name in 
the type name, and just call these `core.interpolation.Header`, 
`core.interpolation.Footer`, `core.interpolation.Literal`, and 
`core.interpolation.Expression`. However, the names of these 
types are going to show up in user-facing error messages without 
the module name attached, so having some kind of prefix to 
distinguish them makes sense.

I agree that `Interpolation` is too long. `i` looks kind of weird 
to me (violates the D style rules about capitalization), but if 
we want brevity above all else, it's a reasonable choice. The 
only other thing I can think of is `Interp`