importizer

Are you looking to convert your header-based C++ codebase to C++20 modules, but afraid that modularizing is too cumbersome? importizer is here to help.

And by modularization I don’t mean exposing a module interface & wrapping headers. I mean native modules a.k.a using modules internally.

This project uses semantic versioning.

Note: This project is currently going through a complete rewrite using Clang LibTooling to replace Regex (pre-2.0.0). Much pre-2.0.0 code are gone, but releases & git history are preserved.

Table of Contents

• Why native C++ modules?
• Prebuilt binaries
• Configuration & usage
  • Command-line interface (CLI)
  • Configuration file (TOML)
  • Example configuration file
• Contributing

Why native C++ modules?

• Improved compilation time: Modules don’t need to be recompiled every time it is imported, unlike headers.

• Improved encapsulation: Modules allow you to choose what is exposed to users (exported), no need to hide stuff with a detail namespace. Includes & macros from a module will only stay in that module.

• arewemodulesyet.org

Prebuilt binaries

Importizer provides pre-compiled binaries for major operating systems. Necessary shared libraries are bundled directly in the distribution archive.

	Linux	macOS	Windows
Architecture	AMD64, ARM64
Minimum OS	None	MacOS 14+	Windows 10+
Format (release)	zst(bin)
Format (debug)	tzst(trampoline + bin + .so)	tzst(bin + .dylib)	tzst(bin + .dll)

• Stable release: Download optimized release builds from the releases page.

• Bleeding edge (debug): Download unoptimized builds from the Continuous release. Useful for testing latest features or reporting bugs.

Configuration & usage

Importizer primarily uses a TOML configuration file, complemented by a few command-line options.

Command-line interface (CLI)

By default, running importizer looks for an importizer.toml file in the current working directory. You can override this by passing the path as a positional argument: importizer path/to/configuration.toml.

Option	Description
-h, --help	Display available options.
--help-list	Display list of available options.
--version	Display version.
-o, --outDir	Override the output directory specified in the configuration file

Configuration file (TOML)

All relative paths in the configuration file are resolved relative to the file’s location, not the current working directory.

Option	Type	Description
inDir	String	Required. The directory containing the source code to process.
outDir	String	Required (unless provided via CLI). The directory for the modularized output.
compilationDb	String	Highly Recommended. Path to a compile_commands.json compilation database to provide context.

Bootstrap mode

For projects without a JSON compilation database, Importizer can attempt to imitate one using the [bootstrap] table. Note: if compilationDb is specified, the bootstrap table is ignored.

Option	Type	Description	Default
ignores	String Array	gitignore-style ignores to exclude non-code files.	["CMakeLists.txt"]
includePaths	Include paths to search during resolution.	String Array	[]

Example configuration file

inDir = "src"
outDir = "modular_src"
# compilationDb = "build/compile_commands.json"

[bootstrap]
includePaths = ["include", "third_party/libs"]

Contributing