I think "injectMany" would be a good addition.
It looks like a useful feature and it's important to keep up with the
features added in Java.
Some silly brainstorming for method name:
injectAccumulate (or injectAcc)
injectAll
/Mattias
Den tis 25 mars 2025 kl 13:30 skrev Paul King <pa...@asert.com.au>:
> Hi folks,
>
> JDK24 brought with it the Gatherers API for enhanced stream processing.
>
> In traditional streams, we have the normal reduce operators, e.g.:
>
> var nums = 1..3
> assert nums.stream().reduce('', (String string, number) -> string +
> number) == '123'
>
> Groovy supports this for collections using "inject":
>
> assert nums.inject(''){ carry, next -> carry + next } == '123'
>
> But now there is also the prefix sum variant "scan", which I am told
> has a myriad of uses, though I don't commonly use it myself. Note it
> has the same reduce function as above:
>
> assert nums.stream()
> .gather(Gatherers.scan(() -> '', (string, number) -> string + number))
> .toList() == ['1', '12', '123']
>
> We can also emulate this for collections (with a little ugliness)
> using the vanilla inject:
>
> assert nums.inject([]) { sum, next ->
> [*sum, "${sum.takeRight(1)[0] ?: ''}$next"]
> } == ['1', '12', '123']
>
> I am wondering whether we could actually provide the same
> functionality as scan above, something like this (name "injectMany"
> currently but open to a better name):
>
> assert nums.injectMany(''){ carry, next -> carry + next } == ['1', '12',
> '123']
>
> It is only a minor change to the inject code, so not a huge technical
> challenge, but what do folks think? Should we round out our collection
> support to provide similar functionality to that available in streams?
>
> Regards,
> Paul.
>
