Range golf challenge: apply predicate to a subrange, returning the original range modified.

[Ali Çehreli]

On 10/7/22 12:19, FeepingCreature wrote:
 > On Friday, 7 October 2022 at 16:49:33 UTC, rassoc wrote:
 >> On 10/7/22 16:00, FeepingCreature via Digitalmars-d wrote:
 >>> Thoughts?
 >>
 >> How about your selector func wraps the elements, similar to Nullable
 >> or via SumType, and your modifier func operates on the marked ones
 >> during iteration while returning the others as is? Poor man's monads?
 >
 > Y'all are missing the point a bit. :)

It's because of your example! :)

 > The type spec of the selector is "takes a range, returns a subrange." A
 > subrange here being "a range like the original but with some amount of
 > elements missing."

Your example does not miss the "missing" elements (the odd ones):

   assert(result.equal([0, 1, 4, 3, 8, 5, 12, 7, 16, 9]));

Maybe you mean selectSubrange is already written and does miss some 
elements and the goal is to merge those back into where they were 
missing from.

Ali