A node is the basic building block of LogicSim. A node is a GenServer that has 0 or more inputs, and 0 or more outputs. Each node keeps track of which nodes are connected to each of its outputs. When an output changes the node sends a message to its connected nodes telling them what value to set on the input they are conneted to.

Nodes are modules that use LogicSim.Node as demonstrated below, optionally specifying a list of inputs, a list of outputs, and/or a map with additional state:

defmodule LogicSim.Node.Or do
  use LogicSim.Node, inputs: [:a, :b], outputs: [:a]

defmodule LogicSim.Node.OnOffSwitch do
  use LogicSim.Node, outputs: [:a], additional_state: %{on: false}

and implement the callback calculate_outputs/2 to generate all output values given the current input values as demonstrated here (the Not gate):

def calculate_outputs(_state, %{a: a} = _input_values) do
  %{a: !a}
end