# `Issho.Actor`
[🔗](https://github.com/hattoriai/issho/blob/v0.1.0/lib/issho/actor.ex#L1)

Anyone or anything that takes part in a room: a user, an admin, a guest,
a service, an agent. Issho never assumes your schema; implement this
protocol for each struct that can join.

    defimpl Issho.Actor, for: MyApp.Accounts.User do
      def key(user), do: "user:#{user.id}"
      def display(user), do: %{name: user.name, avatar: user.avatar_url, kind: :human}
    end

    defimpl Issho.Actor, for: MyApp.Agents.Agent do
      def key(agent), do: "agent:#{agent.id}"
      def display(agent), do: %{name: agent.name, kind: :agent}
    end

`key/1` is the actor's identity in every room: namespace it, so that
admin 4 is not user 4. Two tabs of one actor share a key, and others see
one person.

`display/1` is what the other people in a room see, so give it only what
they may see: `:name`, `:avatar` (an image's URL), `:color` (a CSS
colour) and `:kind` (`:human`, `:agent` or `:service`, `:human` unless
given). Issho checks the colour before it reaches anyone's browser.

Maps with an `:id` work without an implementation, for scripts and
tests: `%{id: 4, name: "Ada"}` is the actor `"4"`.

# `t`

```elixir
@type t() :: term()
```

All the types that implement this protocol.

# `display`

```elixir
@spec display(t()) :: map()
```

What the other people in a room see of the actor.

# `key`

```elixir
@spec key(t()) :: String.t()
```

The actor's identity in every room, the same in every tab and node.

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