Rain: Automatic Reflection for C++

Requirements

You will need Python 3.10 and the libclang pip package.

Examples

Setup: Meson

This process will likely change.

Add rain as a subproject. Assume you have all your .cpp files in proj_src. You want to generate a .meta.json file for each, and then combine them into an rtti.cpp file that you can link normally.

rain     = subproject('rain')
rain_dep = rain.get_variable('rain_dep')

...

python = import('python').find_installation('python3')

# Build meta files
proj_meta = []
foreach file : proj_src
    fs = import('fs')
    proj_meta += custom_target(
        fs.name(file) + '.meta.json',
        output: fs.name(file) + '.meta.json',
        input: [rain.get_variable('rain_update_py'), file],
        command: [python, '@INPUT@', '@OUTPUT@'],
        console: true
    )
endforeach

# Build rtti.cpp
proj_rtti = custom_target(
    'rtti.cpp',
    output: 'rtti.cpp',
    input: [rain.get_variable('rain_rtti_py'), proj_meta],
    command: [python, '@INPUT@', '@OUTPUT@', '@CURRENT_SOURCE_DIR@],
    console: true
)

...

proj_exe = executable(files(proj_src), proj_rtti, 
    ...
    link_with: [rain_dep, ...]
)

Structure

The Python scripts are as follows:

• update.py - simply marks a given meta file as stale
• rtti.py - generates a rtti.cpp file from a list of meta files
  • parse.py - actual libclang parsing logic - regenerates stale meta files
    • traverse.py - traverses the AST to produce type info