Proposal: Move primitive-Data.Primitive.Addr API into base

[Sven Panne]

Am Di., 30. Okt. 2018 um 15:18 Uhr schrieb Daniel Cartwright <
chessai1996 at gmail.com>:

> > hPutBuf doesn't care about what stuff has been written into the given
> buffer, it just cares about its start and its size.
> Seems like a good use for Addr?
>

Nope, not at all: Using a free type variable like "a" in such a situation
is *the* common idiom to specify that the function doesn't care about the
type, just like "length" doesn't care about the type of the elements. If
you don't like that idiom, fine, but it has been officially enshrined in
the standard and people are using it for decades (well, almost) without any
problems, at least I haven't heard of them.

What would using Addr buy us? Addr is non-standard, and you would have to
use some cast from a Ptr somehow (the world outside GHC's innards is using
Ptr, not Addr). This would buy you exactly zero safety or clarity, and it
would only introduce API friction.


> > If you have a pointer pointing to something and shift that pointer by
> some bytes, you are probably pointing to something completely different, so
> of course "b" and "a" have nothing to do with each other. So peekByteOff
> intentionally ignores "b".
> This also seems like a good use for Addr?
>
Nope again, see above.

I still fail to see what problem this whole proposal is actually trying to
solve...
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