PPX

Small C-style macro expansion library.

Example

let result = ppx::parse_string(
    "
    #param A
    #define B hello
    #define fn(name) name!
    
    B A fn(John)
    ",
    base_dir,
    ["world"].into_iter()
);
// result = "hello world John!"

More examples in the tests folder.

Features

• #param: A parameter that can be passed when including the file, or from the parse* functions.
• #define: Define a simple substition, or a function-like macro
  • paste operator: use ## to paste two tokens
• #include: Include another file and parse it as well. Optionally accepts parameters which will be used for substituting the names specified by #param.
• #pragma once: only include a file once
• Conditional branching with #if, #elif, #else, #endif

Optional features:

• Macros include_ppx! and include_ppx_string!: Parse a template at compile time instead of at runtime. Enable macros with feature macro or macro-stable.
• vfs feature: allows using virtual filesystem from the vfs crate as the input.

Versioning

This crate follows semantic versioning since 1.0.

Development

Running tests

cargo test --workspace

Or better, with the cargo-all-features subcommand:

cargo +nightly all-features test --workspace

License

MIT or Apache-2.0.