如何将串行 object 作为数字传递（使用 arduino 串行的新库）

Question

I want to create a new library which controls arduino's Serial library.

Here is what I want...

main Sketch

#include <newLibrary.h>

newLibrary connection(2,9600); // 2 is Serial2, 9600 is baudRate

void main()
{
   connection.start();
}

newLibrary.cpp

newLibrary::newLibrary (uint8_t port, long baudRate)
{
   __port = port;
   __baudRate = baudRate;
}

void newLibrary::start()
{
   (Serial+port).begin(); // I need to add port to Serial to make Serial2
}

What I want to do is,

The user will choose which Serial port(eg. Serial/Serial1/Serial2 etc...) is going to be used with;

newLibrary connection(2,9600);  // 2 is Serial2, 9600 is baudRate

and after that the start function in newLibrary.h will start that Serial port with an algorithm like;

void newLibrary::start()
{
   (Serial+port).begin(); //  Which is equal to Serial.begin() or Serial1.begin() etc
}

I know it can be done by if statement or switch case...

But is there another way?

Such as macros....

I know that the macros can be used like;

#define serialPort (Serial##1) // so the serialPort refers to Serial1

But this way doesnt work for me....

Answer 1

C++ doesn't supportreflection . You can't build variable names at runtime.

You could store pointers to the objects in a container.

#include <array>

class S {
public:
    void begin() {}
} Serial, Serial1, Serial2;

int main() {
    std::array serials = {&Serial, &Serial1, &Serial2};
    std::uint8_t port = 1;
    serials[port]->begin();
}

Answer 2

Instead of taking a uint8_t why don't you take a Stream object and then you can pass Serial2 directly like: newLibrary connection(Serial2,9600);

newLibrary::newLibrary (Stream port, long baudRate)
{
   __port = port;
   __baudRate = baudRate;
}


newLibrary connection(Serial2,9600);



void newLibrary::start()
{
   _port.begin(_baudRate); //  Which is equal to Serial.begin() or Serial1.begin() etc
}

Of course you also need to change the line in the class definition that defines _port, but since you didn't post that bit I'll assume you know how to do that.

Moral of the story is, those serial ports are objects of type Stream, so you can pass them around just like variables as long as you use the type Stream instead of int or byte or char.