On Friday, 11 September 2015 at 13:31:06 UTC, John Colvin wrote:
On Friday, 11 September 2015 at 13:09:33 UTC, Laeeth Isharc
wrote:
obviously it's trivial to do with a little aa cache. and I
know I can memoize a function, and turn the memoized version
into an infinite range. but suppose I have a lazy function
that returns a finite range, and its expensive to calculate.
can I use Phobos to produce a memoized range? So it will
calculate on access to an element if it needs to, but will
return the cached value if it has been calculated before.
perhaps
http://dlang.org/phobos/std_algorithm_iteration.html#.cache
would do what you need. An AA based cache (with a normal range
interface if you want) is probably the sensible way to get true
random-access here, unless you have reasonably dense and
monotonic accesses in which case an appender-based linear cache
could work, either using Nullable!T or a separate list of bools
(or bits) marking whether a result is cached yet.
Thanks, John and Jacob.
Laeeth.
