# `Issho.Engine.Map`
[🔗](https://github.com/hattoriai/issho/blob/v0.1.0/lib/issho/engine/map.ex#L1)

A map that people and agents change together: values at paths, in the
order the authority accepts them. It is the engine of shared assigns, the
reference for writing an engine, and the engine of Issho's own tests.

    %{"op" => "set", "path" => ["plan", "title"], "value" => "Q3"}
    %{"op" => "delete", "path" => ["plan", "draft"]}
    %{"op" => "increment", "path" => ["votes"], "by" => 1}

A path is a list of up to 16 strings. `set` makes the maps on its way;
`delete` of a missing key does nothing. Concurrent `set`s of one path
follow the authority's order; `increment`s add up. The initial content is
a map (or `nil`, an empty one).

Options: `:max_depth` of values (32).

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