Behaviors

Agents can (and typically do) have behaviors:

{
    ...
    behaviors: ['eats_fruit', 'messages_friends_about_fruit', 'has_friends']
}

Behaviors allow agents to have agency in the simulation. An agent can have any number of behaviors.

Behaviors are pure functions in the form of: (current_state, context) => [next_state]

The exact semantics vary by programming language, but in spirit every behavior is a pure function which receives a given agent's state, the world context visible to that agent, and outputs its next state.

Most behaviors output a single state with the same agent_id as they received. For example, the following behavior code causes an agent to move along the x-axis:

(state, context) => {
    state.position[0] += 1;
    return state;
}

​