# `RustQ.Meta.Lower.MapSet`
[🔗](https://github.com/elixir-crab/rustq/blob/v1.0.0-rc.19/lib/rustq/meta/lower/map_set.ex#L1)

Lowers `MapSet` functions on a `HashSet` or `BTreeSet` for `RustQ.Meta.Lower.Stdlib`, and
types such calls: `new/0` (`new/1,2` are comprehensions; see `RustQ.Meta.Desugar`), `put`, `delete`, `member?`, `union`, `difference`, `intersection`,
`subset?`, `disjoint?`, `size`, and `to_list`. An update takes the set only at its last use;
see `RustQ.Meta.Lower.Collection`.

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*Consult [api-reference.md](api-reference.md) for complete listing*