Creating a .cpp, compiling and executing

[tulicloure]

Hello people,

I'm trying to create a program that dynamically creates strings of code, and as C/C++ is a compiled system, it's not possible to use something like eval() (from JavaScript). So, I thought I could create another .cpp file, compile it, and then execute the .exe. Can someone help me with this?

[turbozedd]

Maybe you need to use system calls. And then you have to consider the problems of portability.
Or , maybe you could include the compiler libraries in your code...but again portability issues.

[tulicloure]

But witch libraries I should use to do this? I've never used C/C++ to execute a .exe file, neither to compile another .cpp. I'll need an example or, at least, the function calls and library names.

[helios]

It sounds terribly risky and error-prone. If you give more details I can probably come up with something. What kind of input will the program take and what should its output be?

[tulicloure]

I'm trying to develop a program that can receive via keyboard new strings of code and execute them. E.g.:

The main program "Main" reads the string from keyboard:
printf("Hello.");
Then, it shows as output:
Hello.

If C/C++ wasn't a compiled system, it would be something like this:

#include <stdlib.h>
#include <iostream>

using namespace std;

#define CODE(code) code

main()
{
   string code;
   
   cin >> code;
   
   CODE(code);
   
   cout << endl << "Press ENTER to exit." << endl;
   cin.ignore();
   cin.ignore(1, '\n' );
}

Then, as it wouldn't work this way, I thought about creating another .cpp file, compile and execute it. It's just a general view of the idea but i think you can get it.

Ah, and the input could be any kind of code in C/C++, like a for, if, scanf, etc.

[Duthomhas]

It probably isn't worth your time to roll your own private interpreter. I suggest you simply embed a pre-made interpreter.

Tcl
http://wiki.tcl.tk/

Python
http://www.python.org/

Scheme
http://www.plt-scheme.org/

You also have to deal with sandbox issues. All of the above are very good at that.

Hope this helps.

[tulicloure]

Thanks guys. I'd really like to make it in C/C++ but I'll wait some years maybe. XD

[turbozedd]

try bison

http://www.gnu.org/software/bison/

You could probably copy the c grammar almost directly.