PyExpand

Write python expressions in C/C++ comments and expand it into code underneath!

Windows-only for now.

Inspired by a tweet by @mmalex:

How to build

1. Download premake5 and Visual Studio 2022.
2. In the root directory, run premake5 vs2022. Open the generated VS solution in the .vs2022 folder and build the solution.
3. The generated executable will be in the .build folder. Add this folder to your PATH environment variable.

Usage

You can run the tool in the command line: PyExpand [file]. This will parse the file for comments of the form /*.py ... */, evaluate the python code inside, and write the result back to the file after the comment and before the next /*.

For example, the following line:

int my_number = /*.py 5*5 - 4 *//**/;

... will expand into

int my_number = /*.py 5*5 - 4 */ 21 /**/;

You can also write multi-line python code, in which case the code should be a python function body that returns a value:

#include <stdio.h>

/*.py
	squares = []
	for i in range(25):
		squares.append(i*i)
	return "int squares[] = {" + str(squares)[1:-1] + "};"
*/
int squares[] = {0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400, 441, 484, 529, 576};
/**/

int main()
{
    for (int i = 0; i < 25; i++)
        printf("Square: %d\n", squares[i]);
    return 0;
}

Using the Visual Studio extension

Double click the VSPyExpand.vsix in the root directory to install the extension into your Visual Studio. The extension adds a "PyExpand" command into the "Tools" menu that runs PyExpand on the currently open file, also bound to Ctrl+Alt+Y. For this to work, you must have the folder containing PyExpand.exe in your PATH!