Andy Ferris

> `count = (length ∘ skipmissing).(groups)` Apparenlty that doesn't work (yet). I got carried away: https://github.com/JuliaLang/julia/pull/35946, https://github.com/JuliaLang/julia/pull/35947

Yes it would be good to support this. Recently I had moved from `Function` to include `Type` as well and expanded the signatures of many of the functions here to...

By the way I’ve been tempted to make a PR to make 'Symbol` callable like that in `Base` - it’s a really nice Clojure feature for example.

> For example, both Base ranges and StaticArrays SVectors turn into plain Vectors There's mitigating facts for those. Ranges don't support `setindex!` and cannot be the output of `similar` (or...

> Still, are there any actual types whose similar output cannot be pushed to? Off the top of my head, _DistributedArrays.jl_ `DArray` has this property. I've created more than one...

While I may somewhat agree with you... I try to follow `Base` semantics here for things like `map`. It might be too late to start fiddling with that (when it...

> For example, mapping a reduce function over truly lazy groups would enable the groupreduce optimization. Unlike most operations where we can just rely on iteration and separation of concerns...

Thanks. I’ll take a look into that. > (I report this issue here rather than under Indexing.jl as I don't see any recent activity there.) Very occasionally, one writes some...

Yes I think this is a good idea, though we need to be careful that dispatch works out. I also thought we might have had something like this? (Perhaps it’s...

Hi @pdeffebach, I finally got some time at the computer and see we already have this behavior: ```julia julia> g = [1, 1, 2, 2] 4-element Array{Int64,1}: 1 1 2...