On Sunday, 30 March 2014 at 21:53:16 UTC, bearophile wrote:
monarch_dodra:
I'm taking this naming-changing event as an opportunity to
"cleanup" reduce too.
This seems OK, but can fold offer a better solution?:
Bye,
bearophile
AFAIK, no: Your range's element type (E) is `const(uint)[]`, and
given your predicate (let's just call it "pred"), `pred(e, e)`
produces a `const(uint)[]`. There's not much that reduce or
fold(l) could do about it at that point.
You'd have two (IMO cleaner) solutions.
1. tweak pred to return the right type (*):
uint[] foo1(uint[][] X)
{
return X.reduce!((i, j) => zip(i, j)
.map!(kw => uint(kw[0] | kw[1]))
.array);
}
(*) This currently fails catastrophically with both single and
multiple pred versions of reduce, due to suboptimal code.
I can get it to work for fold though.
2. provide a seed.
uint[] foo1(uint[][] X)
{
return reduce!((i, j) => zip(i, j)
.map!(kw => uint(kw[0] | kw[1]))
.array)([uint(0), uint(0)], X);
}
In any case, thanks for reporting. I'll make certain this works.
