Licensing

pxx is licensed per directory. Every source file carries a one-line SPDX-License-Identifier header; this table is the map.

Path License Text
compiler/** (except compiler/builtin/) MPL 2.0 LICENSE
tools/** MPL 2.0 LICENSE
compiler/builtin/**, lib/rtl/**, lib/pcl/**, lib/crtl/**, lib/asmcore/** zlib licenses/Zlib.txt
examples/** 0BSD licenses/0BSD.txt
docs/** CC BY 4.0 https://creativecommons.org/licenses/by/4.0/
everything else (tests, devdocs, build files) MPL 2.0 LICENSE

Why the split: the runtime and libraries under zlib are embedded into every binary the compiler produces — programs you compile with pxx are entirely yours, with no license obligations from the toolchain. The compiler itself is MPL 2.0: use it anywhere, link it with anything, but published modifications to its files stay open.

Compiled output

Binaries produced by the compiler belong to their author. The runtime code embedded in them is zlib-licensed, which imposes no requirements on binary distribution.

Contributions

External contributions require a Developer Certificate of Origin sign-off (git commit -s) and include a contributor license grant that permits the project to relicense contributed code if the project license ever needs to change; see CONTRIBUTING.md.

Third-party code

The repository contains no third-party code. Optional external material (the Lua test corpus, library candidate sources fetched by tools/install_lib_candidates.sh) is downloaded locally on demand, lives in git-ignored directories, and keeps its own upstream licenses.

No warranty

The software is provided "as is", without warranty of any kind. It is under active development; see each license text for the full disclaimer.