GreyTalonSRX-demo.cpp

#include <stdio.h>
#include <cmath>

struct TalonPIDConfig {
    float p = 0.0;
    float i = 0.0;
    float d = 0.0;
    float f = 0.0;
};

/**
 * A TalonConfig object might have a field for every configerable
 * option that is pre-populated with a sane value
 **/
struct TalonConfig {
    bool inverted = false;
    TalonPIDConfig pid_0 = { 0.0, 0.0, 0.0, 0.0 };
    float continuousCurrentLimit = 40.0; /* ContinuousCurrentLimit */
    float voltageCap = NAN;              /* VoltageCompSaturation */
};

class TalonSRX {
private:
    int m_canId;
public:
    TalonSRX(int canId): m_canId(canId) {}
};

class GreyTalonSRX: public TalonSRX {
public:
    /**
     * The constructor in GreyTalonSRX could take a TalonConfig object
     * that has a bunch of default values but where any of those values can be
     * over-written
     **/
    GreyTalonSRX(int canId, TalonConfig config)
            : TalonSRX(canId) {
        printf("  Inverted: %d\n", config.inverted);
        printf("  PID_0: { %f %f %f %f }\n", config.pid_0.p, config.pid_0.i,
               config.pid_0.d, config.pid_0.f);

        /* Having one field for configuring current-limit would prevent mistakes
           like setting (but not enabling) current limit */
        printf("  CurrentLimitEnabled: %d\n",
               config.continuousCurrentLimit == config.continuousCurrentLimit);
        printf("  CurrentLimit: %f\n", config.continuousCurrentLimit);

        printf("  VoltageCapEnabled: %d\n",
               config.voltageCap == config.voltageCap);
        printf("  VoltageCap: %f\n", config.voltageCap);
    }
};

int main(void) {
    TalonConfig conf = {};
    /* You could make a TalonConfig object that pre-populates with sane defaults
       then you could change whatever fields you wanted */

    conf.inverted = true;
    conf.pid_0 = {
        /* If you forget one of these fields you will get a compile error */
        p : 8,
        i : 2,
        d : 6,
        f : 8,
    };

    TalonSRX *talon = new GreyTalonSRX(9, conf);
}

Output.txt

  Inverted: 1
  PID_0: { 8.000000 2.000000 6.000000 8.000000 }
  CurrentLimitEnabled: 1
  CurrentLimit: 40.000000
  VoltageCapEnabled: 0
  VoltageCap: nan