Very useful templates for anyone interfacing with C. Thank you very much.
Since I usually do a lot of pointer work in a given file, I switched to this:
template usePtr*[T]() =
template `+`(p: ptr T, off: Natural): ptr T =
cast[ptr type(p[])](cast[ByteAddress](p) +% int(off) * sizeof(p[]))
template `+=`(p: ptr T, off: Natural) =
p = p + off
template `-`(p: ptr T, off: Natural): ptr T =
cast[ptr type(p[])](cast[ByteAddress](p) -% int(off) * sizeof(p[]))
template `-=`(p: ptr T, off: Natural) =
p = p - int(off)
template `[]`(p: ptr T, off: Natural): T =
(p + int(off))[]
template `[]=`(p: ptr T, off: Natural, val: T) =
(p + off)[] = val
...
usePtr[my_type]()
Note the use of `Natural`. C coders often use unsigned for bit manipulations or
array indices, and **c2nim** converts those to `cuint`, which do not work for
array look-ups.
Actually, I wonder why `uint` is not used for **Nim** bit manipulators.
"Signed" operations are confusing. Do you know the reason? (`ByteAddress` is
`int` now, btw.
[https://nim-lang.org/docs/system.html#ByteAddress](https://nim-lang.org/docs/system.html#ByteAddress)
)
