[API Proposal]: Extend the reduce and reduceBack to Collections

Background and motivation

From the requirements point of view: the fold function must provide init, reduce does not require init, which means no longer needs to write boilerplate "match with" code like "extract the first element from generic Collections as init, the remaining elements as sequence, and then pass it to fold".

From a reasonable point of view: list/array/seq all provide native reduce methods, list/array also provides native reduceBack methods. This generic encapsulation is not difficult to implement, and other languages ​​(except fundamental FPs like Haskell) generally provide reduce methods, which is reasonable.

I know there is a reduce function implementation now, but that one is very difficult to use. To be honest, I have no idea how to pass parameters.

API Proposal

let inline reduce (folder: 'State->'T->'State) (foldable: '``Foldable<'T>``) : 'State

let inline reduceBack (folder: 'T->'State->'State) (foldable: '``Foldable<'T>``) : 'State

API Usage

reduce (*) [1; 2; 3; 4; 5] |> should equal 120
reduce (+) ([]: int list) // throws an exception

Alternative Designs

No response

Risks

No response

Are you willing to help with a proof-of-concept (as PR in that or a separate repo) first and as pull-request later on?

Yes, please assign this issue to me.

Start by reading the existing reduce function implementation and the 41-comment discussion to understand the unresolved API concerns. Compare the proposed reduce and reduceBack signatures with the native list, array, and seq operations. Done means an agreed design and proof-of-concept covering generic collections and empty-input behavior.