Example of Coq Plugin using Dune

Hi all, this repository contains a template for writing a Coq plugin using the Dune build system. It showcases a few advanced features such as linking to C code or to external libraries.

The current version requires:

• Dune 1.10
• Coq 8.10 [the v8.9 branch has a version that will work with Coq 8.9]

See Coq Dune documentation for more help.

See also

https://github.com/coq/coq/tree/master/doc/plugin_tutorial , which already includes dune files for their ML part.

How to build

$ dune build

and the rest of regular Dune commands, to test

$ dune exec -- coqtop -R _build/default/theories MyPlugin

this will be improved soon.

Composing with Coq

You can symlink the Coq >= 8.10 sources in your plugin tree and you will get a composed build, with some caveats:

• you should run make -f Makefile.dune voboot]
• you should call Coq's configure with the a correct install path

this will be improved soon so things work out of the box.

Linking with external libraries

If your plugin depends on an external OCaml library, Coq will fail to load it as it doesn't know about this dependency.

This should be fixed in Coq hopefully soon, see Coq's issue.

Meanwhile, you need to manage the dependency chain manually; imagine you want to depend on z3, then in your (library ...) stanza you want to add:

  (libraries coq.vernac z3)

That is cool, and your plugin will now be able to link to z3, however, when dynamically loading it, you must ensure that the z3 modules have been linked.

To do so manually, load the z3 plugin in your Test.v file:

Declare ML Module "z3ml".
Declare ML Module "example_plugin".

We are almost there! A last thing you need to do is to workaround a Coq Dune bug and add z3 to the list of dependencies of your theory:

 (libraries z3 my-plugin.plugin))

and that's all!

A last step to make things work in the concrete case of z3 is to update the LD_LIBRARY_PATH as the OPAM package is buggy, usually this will do:

export LD_LIBRARY_PATH=~/.opam/coq.dev/lib/z3:$LD_LIBRARY_PATH

Caveats

• Coq's linker cannot track dependencies properly, thus YMMV when linking against 3rd party libs, see
• coqdep emits some warnings that should be hard failures, we recommend you treat them as such.