# Installation

You have two options to integrate pkpy into your project.

# Use the single header file

Download the pocketpy.h on our GitHub Release page. And #include it in your project.

# Use CMake

Clone the whole repository as a submodule in your project, You need Python 3 installed on your system because CMakeLists.txt requires it to generate some files.

In your CMakelists.txt, add the following lines:

option(PK_BUILD_STATIC_LIB "Build static library" ON)
add_subdirectory(pocketpy)
target_link_libraries(your_target pocketpy)

These variables can be set to control the build process:

PK_BUILD_STATIC_LIB - Build the static library
PK_BUILD_SHARED_LIB - Build the shared library
PK_USE_BOX2D - Build with Box2D module

See CMakeLists.txt for details.

# Compile flags

To compile it with your project, these flags must be set:

--std=c++17 flag must be set
Exception must be enabled

# Example

#include "pocketpy.h"

using namespace pkpy;

int main(){
    // Create a virtual machine
    VM* vm = new VM();
    
    // Hello world!
    vm->exec("print('Hello world!')", "main.py", EXEC_MODE);

    // Create a list
    vm->exec("a = [1, 2, 3]", "main.py", EXEC_MODE);

    // Eval the sum of the list
    PyObject* result = vm->exec("sum(a)", "<eval>", EVAL_MODE);
    std::cout << CAST(int, result);   // 6
    return 0;
}

# Overview

pkpy's C++ interfaces are organized in an object-oriented way. All classes are located in pkpy namespace.

The most important class is the VM class. A VM instance is a python virtual machine which holds all necessary runtime states, including callstack, modules, variables, etc.

A process can have multiple VM instances. Each VM instance is independent from each other.

Always use C++ new operator to create a VM instance. DO NOT declare it on the stack.

VM* vm = new VM();

The constructor can take 1 extra parameters.

# `VM(bool enable_os=true)`

enable_os, whether to enable OS-related features or not. This setting controls the availability of priviledged modules such os io and os as well as builtin function open.

When you are done with the VM instance, use delete operator to dispose it.

delete vm;

# Hook standard buffer

By default, pkpy outputs all messages and errors to stdout and stderr. You can redirect them to your own buffer by setting vm->_stdout and vm->_stderr.

These two fields are C function pointers PrintFunc with the following signature:

typedef void(*PrintFunc)(VM*, const char*, int)