unikernel/duniverse/ppxlib/README.md

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+# Ppxlib - Meta-programming for OCaml
+
+[![ocaml-ci status][ocaml-ci-img]][ocaml-ci] [![trunk-build-status][trunk-build-img]][trunk-build] [![AppVeyor status][appveyor-img]][appveyor]
+
+[ocaml-ci]: https://ci.ocamllabs.io/github/ocaml-ppx/ppxlib
+[ocaml-ci-img]: https://img.shields.io/endpoint?url=https%3A%2F%2Fci.ocamllabs.io%2Fbadge%2Focaml-ppx%2Fppxlib%2Fmain&logo=ocaml
+[appveyor]:       https://ci.appveyor.com/project/diml/ppxlib/branch/main
+[appveyor-img]:   https://ci.appveyor.com/api/projects/status/bogbsm33uvh083jx?svg=true
+[trunk-build]: https://github.com/ocaml-ppx/ppxlib/actions/workflows/trunk-build.yml
+[trunk-build-img]: https://github.com/ocaml-ppx/ppxlib/actions/workflows/trunk-build.yml/badge.svg?branch=main
+
+[Ppxlib documentation][doc]
+
+# Overview
+
+Ppxlib is the standard library for ppx rewriters and other programs
+that manipulate the in-memory representation of OCaml programs, a.k.a.
+the "Parsetree".
+
+It also comes bundled with two ppx rewriters that are commonly used to
+write tools that manipulate and/or generate Parsetree values:
+`ppxlib.metaquot`, which allows constructing Parsetree values using the
+OCaml syntax directly, and `ppxlib.traverse`, which provides various
+ways of automatically traversing values of a given type, in particular
+allowing to inject a complex structured value into generated code.
+
+For more information about ppxlib and how to use it, please consult the
+[documentation][doc].
+
+# What is the relation between ppxlib and other ppx libraries?
+
+The ppx world has a long and storied history, and if you look around, you
+may find other projects that offer functionalities similar to
+ppxlib. The following [blog post][future-of-ppx] gives a good overview
+of the various libraries that have been developed over time. At this
+point, ppxlib is considered the de facto library for writing ppx
+rewriters.
+
+# History of the project
+
+This repository was created by merging several older smaller projects
+that were developed at Jane Street. See [the history](HISTORY.md) for
+more details.
+
+[doc]: https://ocaml-ppx.github.io/ppxlib/ppxlib/index.html
+[future-of-ppx]: https://discuss.ocaml.org/t/the-future-of-ppx/3766