Switch device

switch.h

#pragma once
#include "device.h"

// this device represents a switch that can be open or closed.
class Switch : public Device {
 protected:
  // the pin the switch is connected to.
  const uint8_t pin;

 public:
  // scalar events support ->is(value)
  ScalarEvent<bool> state;

  // constructor -- sets up the pin and how often to check
  Switch(const uint8_t pin, const unsigned long interval = 50)
      : pin(pin) {
    pinMode(pin, INPUT);
    repeat(interval);
  }

  // good devices will reset their event listeners when reset
  // (this happens during state changes)
  void reset() {
    state.reset();
  }

  void loop() {
    // in our loop, all we have to do is check the state of 
    // the pin and let the event manage triggering the handler
    state.invoke((digitalRead(pin) != HIGH));
  }

  // this lets us have the event on the device directly
  // so instead of saying:
  //   when( switch->state.is(closed) , { ... } );
  // we can just say:
  //   when( switch->is(closed), { ... } );
  inline Event& is(bool value) {
    return state.is(value);
  }
};