fused-effects VS either

Languages such as Koka only support algebraic effects, not scoping operations such as catch and listen. The Effect Handlers in Scope paper introduces scoping operations, which lead to the Haskell libraries fused-effects and polysemy, but they turned out to have some weird semantics. eff is her effort to fix that.

Restricting what can go into a Result in the error variant is quite restrictive. It's often very convenient to use Result as a sort of "this or that" type without any connotations about errors, particularly as an internal convenience. Arguably one might want to use either instead, but it's a lot of ceremony to bring that in for simple use cases.

P.S. you can use either to make it work on stable rustc

The European Union does not have as large a software industry as the USA so there would be a less strong argument of government/corporate competition. It could take the form of government grants depending on the size. My rationale is that governments benefit from the general prosperity of open source more so than solo authors or small companies.

I am restricting the scope to simple and small libraries where investment is more clearly beneficial unlike Tensorflow as that is large and complex.

Here is an extreme example, the 'either' crate is a 'rayon' dependency and many others. Paradoxically a project of this size likely does not need funding but it is really important.

https://github.com/bluss/either