Only a single function argument can be the optic target about accessors.jl

[aplavin]

It's kinda expected, in the sense that there is no obvious thing to return.
What actual value would you expect from (@views @optic _[2:lastindex(_)]), or equivalently from @optic Base.maybeview(_, 2:lastindex(_))? And how optics functions like set() should work with it?

Regular getindex with _ in the indexing expression is handled explicitly with

Accessors.jl/src/optics.jl

Line 439 in e862651

struct DynamicIndexLens{F}

because this is a reasonably common scenario for optics.

[aplavin]

Actually, maybe instead of erroring, @optic could just return an anonymous function in such cases? Of course, set() won't work then, but it still can be convenient...
What's your actual usecase @jariji?

[jariji]

I'm not clear on exactly what I wanted here. Maybe I'll come back to it another time.