I m trying to ~miss~ use the Effect API to make a partial re

Question

I m trying to ~miss~ use the Effect API to make a partial reduce comprehension like I mentioned to < raulraja> but I seem to get this compilation error blob thinking upside down I m not 100 sure of what I m doing sweat smile cc < simon vergauwen>

pablisco · Answer

Never mind it didn t like the anonymous instance This seems to work sunglasses

pablisco · Answer

I may use a interface to avoid leaking the Effect internal details thinking face

raulraja · Answer

based on the stacktrace you have in the first one you found a problem in the inliner in the ASM compiler module Can you reproduce it in 1 5 with IR on In whatever case maybe worth reporting

pablisco · Answer

I ll see if I can make an independent reproducible example I ll add it as a task on GH so I don t forget or maybe someone can pick it up Either way I m happy that I got it working sunglasses I ll try to add some docs and open a PR later today crossed fingers

simon.vergauwen · Answer

Cool so this is like a DSL for `reduceOrNull` <https docs w3cub com kotlin api latest jvm stdlib kotlin collections reduce or null>

pablisco · Answer

pablisco · Answer

< simon vergauwen> Is like `reduceOrNull` but with comprehensions for iterating skipping elements of a list iterable gonna make a reversed one for Lists I m still not sure about the name the hardest thing in programming

simon.vergauwen · Answer

I do really like the explicit `orNull` in the Kotlin API naming

simon.vergauwen · Answer

This could be considered folding and or reducing so thinking face Ye naming is hard sweat smile

pablisco · Answer

`partialReduceOrNull`

pablisco · Answer

I thought that the partial is appropriate as we could potentially not iterate the whole collection Could also create a `partialFoldOrNull` to provide an accumulator slightly smiling face

pablisco · Answer

Actually thinking of it we could have both `partialReduceOrNull` for `R ` and without the `orNull` with either a `kotlin Result` `Either` or `Validated` I m not 100 sure which would be best We don t tend to use `kotlin Result` as exceptions are heavy thinking face Something like `Either lt R IterationFailure gt ` may be better and we can always provide an extension to make it a `Result`

simon.vergauwen · Answer

It doesn t really make sense to have `Either lt X R gt ` over `R ` unless you have additional information you can share with the consumer about the error Afaik here only 1 error can occur which is that you request more elements than are available right

pablisco · Answer

I was thinking that we can communicate where it failed to make it easier to debug thinking face But maybe we can do it later on if there is a requirement After all we can see the original list and see how many items we have

simon.vergauwen · Answer

Where it failed so something like `data class ReductionFailure val originalSize Int val requestedIndex Int ` That is definitely possible but it would also require more state overhead inside the DSL since you need to keep track of how many times `next ` was called etc

pablisco · Answer

Yeah totally that overhead for the happy path is probably enough to not warrant it 100 I ll keep it simple slightly smiling face I guess the other question would be whether to make it eager or allow suspension by default thinking face

pablisco · Answer

Open to suggestions <https github com arrow kt arrow pull 2396|here> slightly smiling face