Tolc demo

This is a demo over how to use Tolc the bindings compiler. The goal is to make it trivial to use C++ from other languages.

This repo contains the project MyCppLib that exposes just a simple function Hello::cppFunction that we want to use from python, Objective-C and javascript.

In the CMakeLists.txt we download the latest version of Tolc and uses the tolc_create_bindings function provided by the Tolc package. When the bindings are built, the deliverables are copied to the corresponding directory (./python, ./objc, and ./wasm). In order to know what to copy we pass -Dlanguage=python at configure time.

Prerequisites

You need the following installed locally:

• CMake (version >=3.15)
• python3
• For python bindings:
  • python headers (python3-dev on Debian/Ubuntu, usually included elsewhere)
• For WebAssembly bindings:
  • node - To run the WebAssembly example
• For Objective-C bindings:
  • MacOS - Depends on the Foundation library provided by MacOS

Building and using

Python

Configure the build files:

$ cmake -S. -Bbuild-py -Dlanguage=python

Build the module:

$ cmake --build build-py

Since this copies the built artifacts (e.g. MyCppLib.cpython-39-darwin.so) to ./python we can now run:

$ python3 python/main.py

Objective-C

Note that this only works on MacOS.

Configure the build files:

$ cmake -S. -Bbuild-objc -Dlanguage=objc

Build the module:

$ cmake --build build-objc

You can now find the built Objective-C library with the corresponding header in the objc directory.

Run the example code (./objc/main.m:

$ ./build-objc/main

WebAssembly

We'll start by downloading and configuring Emscripten. Their SDK is stored as a submodule in this repository so all we have to do is:

$ git submodule update --init
$ cd emsdk
# Download Emscripten to emsdk/upstream
$ ./emsdk install 3.1.3
# Write the .emscripten config file
$ ./emsdk activate 3.1.3

Or any later version of emsdk.

Note that for Windows you switch out ./emsdk for emsdk.bat. Now we can build the actual project.

Configure the build files:

$ cmake -S. -Bbuild-wasm -Dlanguage=wasm -DCMAKE_TOOLCHAIN_FILE=emsdk/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake

Note that the / is used as a directory separator even on Windows.

Build the module:

$ cmake --build build-wasm
$ node wasm/main.js

Since this copies the built artifacts (MyCppLib.js and MyCppLib.wasm) to ./wasm we can now run:

$ node wasm/main.js

You can read more over at the documentation for Tolc.