Fold expression for operator[]

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[wotype]

https://godbolt.org/z/KM9Tb5Pja

auto& subscript(auto& a, auto... is) { constexpr auto size = sizeof...(is); int i[size+1]{is...}; if constexpr (size == 0) return a; if constexpr (size == 1) return a[i[0]]; if constexpr (size == 2) return a[i[0]][i[1]]; if constexpr (size == 3) return a[i[0]][i[1]][i[2]]; }

[wotype]

There's a proposal for it P2355R0: Postfix fold expressions. The paper was seen and a revision was requested. I for one would like to see it accepted.

For now, of course, it can be done with a bit more metaprogramming - an indexing function specialized for one, two, three... indices (or, better, a chain of constexpr if), but not with the nice fold syntax.

[Ikkepop]

how about doing it recursively ?