I would like to throw in my implementation that is inspired by `std::transform`
from c++.
proc genRangeswap[Coll](data: var Coll; s0, s1, N: Natural): void =
for i in 0 ..< N:
swap(data[s0+i], data[s1+i])
proc genTransform[Coll](data: var Coll; first, middle, l
I would call it transform like in `std::transform` from c++ ``. But
then it should also rotate elements, meaning that elements dropping out from
the left, should also reenter from the right. And to complete the functionality
of std::transform, it should also be possible to pass subranges of a se
@jlp765 : yeah probably, and stefan said that, but I find this interesting :)
So, based on [this
thread](http://forum.nim-lang.org///forum.nim-lang.org/t/1471/2) , using reset
on the elements we move out of the array should handle ref etc. properly.
The code becomes this:
proc sh
If you are wanting to remove elements from the start of the seq and shift data
elements to the front,
shouldn't you be [using a
queue](http://forum.nim-lang.org///nim-lang.org/docs/queues.html) rather than a
sequence?
I was thinking about refs too and I kinda doubt that just moving the refs in
memory works. Sequtils usually uses `shallowCopy()` for manipulation of
elements in the seq. Which imho avoids (deep) copying a string or seq inside
the seq and copies the "pointer" (reference). I guess OP shift() proc
@OderWat: do you mean something like this?
proc shift[T](a: var openarray[T]; d: int) =
if d == 0: discard # do nothing
elif abs(d) >= a.len: # reset all
zeroMem(addr a[0], a.len*sizeof(T))
elif d > 0: # right shift
moveMem(addr a[d], addr a[0], (a.le
@OderWat
Sorry, can not really understand... Somethink like memCopy or memMove? That was
my first idea, but I was very unsure what would happen when array elements are
not somethink like plain ints, but objects with refs. Would that confuse the GC?
And of course one may ask if array shifting is
Would "shifting" a seq or even an array not just be one operation operation for
all elements at once and then initialisation of the remaining fields with 0
because an array/seq has continuous memory layout and the default init is
"zeroing memory" afaik.
Yes, for some languages shift may mean returning an element. But in Nim we have
shl and shr operators. scroll may be confused with rotation?
I will look at your code in more detail tonigth -- you are using magic reset
proc from system module. I tried also a year ago, then I asked Araq in IRC
ab
Nice, though I'm used to shift meaning "remove the first value of the
(resizable) array and return the value", I think your proc feels more like it's
"scrolling" the array?
Anyway, naming aside, what do you think of this version?
proc scroll[T](a: var openarray[T]; d: int) =
Do we have a shift operation for array elements in Nim like this one? Well, now
we have.
The filling with default value: I am using a compiler initialized var to get
the default. Is that the suggested way?
proc shift[T](a: var openarray[T]; d: int) =
## Shift a right by d
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