Select behavior (methods) at compile time

Projects Programming
7

Normally, you'd have three classes that implement virtual methods.

To do what you describe, you could use a 'strategy' pattern. The timer class would be a wrapper around an implementation which would be created in the constructor.

class ColorPrinter {
    class Impl {
      public:
        virtual void printMe() = 0;
    };

    class RedImpl : Impl {
        void printMe() {
          Serial.print("RED");
        }
    };

    class GreenImpl : Impl {
        void printMe() {
          Serial.print("GREEN");
        }
    };

    const Impl *impl;

  public:

    ColorPrinter(boolean useRed) : impl( useRed ? (Impl*) new RedImpl() : (Impl*) new GreenImpl()) {
    }

    void print() {
      impl->printMe();
    }

};

ColorPrinter redPrinter(true);
ColorPrinter greenPrinter(false);

void setup() {
  Serial.begin(9600);

  Serial.print("redPrinter.print() = ");
  redPrinter.print();
  Serial.println();

  Serial.print("greenPrinter.print() = ");
  greenPrinter.print();
  Serial.println();
}

void loop() {
}