Parser/viewer for olean files, written in Rust and Lean.

See olean.lean for the lean version, and build with cargo for the Rust version. Currently the Rust version is faster by a factor of a hundred or so, so I don't know if I will continue to keep the Lean version up to speed.

Why look at olean files? The olean file format is an unstable binary format used by lean for caching successfully parsed files. As such, it is much easier to parse from a third party position than a lean file. Second, although lean supports an export format, the format is quite lossy, essentially only representing the expressions that are defined in the file. By contrast, the olean file contains lots of other information like notation declarations, attributes, protected status and namespace locations (which are not accessible through lean metaprogramming), and VM code. So olean parsing is the first step to a number of other processing or analysis passes.

rustup toolchain install nightly
rustup override set nightly
cargo build

Usage: target/debug/olean-rs path/to/file.olean [options]

Options:
    -D, --dump FILE      dump olean parse
    -L                   give location of lean library
    -d, --deps lean.name view all dependents of the target file
    -p DIR               set current working directory
    -l lean.name         test lexer
    -t lean.name         testing
    -h, --help           print this help menu