Splitting this from the colour
thread(https://forum.dlang.org/thread/mailman.961.1475765646.2994.digitalmar...@puremagic.com?page=1).
So currently D does not have a way to express batch operations
that work seamlessly with normal ranges.
Manu suggested to use the array operation syntax. I suggest
something along the lines of the following, forwarding any
operations to the static array.
struct InBatchesOfN(size_t N,R) if( N!=0 && isInputRange!R
&&
hasLength!R)
{
R r;
static struct Batch
{
ElementType!(R)[N] elements;
auto get() { return elements[]; }
alias get this;
Batch opBinary(string op)(Batch rhs)
if(hasOperator!(ElementType!(R),op))
{
Batch b;
foreach(i; iota(N)) mixin("b.elements[i] =
elememts[i] "~op~" rhs.elements[i]");
return b;
}
//repeat for opUnary,opOpAssign,opDispatch etc...
}
Batch batch;
this(R _r)
{
// could have overloads where undefined elements ==
ElementType!(R).init
assert(_r.length % N ==0);
r = _r;
foreach( i; iota(N))
{
batch[i] = r.front;
r.popFront;
}
}
bool empty() { return r.empty; }
auto front() { return batch; }
void popFront()
{
foreach(i; iota(N))
{
batch.elements[i] = r.front;
r.popFront;
}
}
}
auto inBatchesOf(size_t N,R)(R r)
{
return InBatchesOfN(r);
}
Thoughts?
