On Friday, 30 March 2018 at 06:11:22 UTC, 9il wrote:
Hello,
Bugfix for the Issue 16486 [1] (originally [2]) is required for
mir-algorithm types [3], [4].
For example, packed triangular matrix can be represented as
Slice!(Contiguous, [1], StairsIterator!(T*))
Slice!(Contiguous, [1],
RetroIterator!(MapIterator!(StairsIterator!(RetroIterator!(T*)), retro)))
They are used in mir-lapack [5]. The bug fix also required for
mir (Sparse, CompressedTensor), and for the future Dlang image
library.
Workarounds aren't interesting.
200$ - bounty ( I can pay directly or transfer money to the
Dlang Foundation )
Best Regards,
Ilya Yaroshenko
[1] https://issues.dlang.org/show_bug.cgi?id=16486
[2] https://issues.dlang.org/show_bug.cgi?id=16465
[3]
http://docs.algorithm.dlang.io/latest/mir_ndslice_slice.html#Slice
[4] http://docs.algorithm.dlang.io/latest/mir_series.html#Series
[5]
https://github.com/libmir/mir-lapack/blob/master/source/mir/lapack.d
Given the recent blog post on std.variant, it occurs to me that
this enhancement would also make writing functions that take
Option types much easier. I'm adopting some of the code from the
blog post below:
import std.variant;
alias Null = typeof(null); //for convenience
alias Option(T) = Algebraic!(T, Null);
Option!size_t indexOf(int[] haystack, int needle) {
foreach (size_t i, int n; haystack)
if (n == needle)
return Option!size_t(i);
return Option!size_t(null);
}
auto foo(T)(VariantN!(T.sizeof, T, typeof(null)) x)
{
return x;
}
auto bar(T : Option!U, U)(T x)
{
return x;
}
auto baz(T)(Option!T x)
{
return x;
}
void main()
{
import std.stdio : writeln;
int[] a = [4, 2, 210, 42, 7];
Option!size_t index = a.indexOf(42);
writeln(index.foo!size_t); //works
//writeln(index.foo); //doesn't work
//writeln(index.bar); //doesn't work
//writeln(index.baz); //doesn't work
}
