https://github.com/epfl-systemf/camltac
OCaml as a Tactic Language for the Rocq Prover
https://github.com/epfl-systemf/camltac
ltac2 ocaml rocq rocq-prover
Last synced: about 23 hours ago
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OCaml as a Tactic Language for the Rocq Prover
- Host: GitHub
- URL: https://github.com/epfl-systemf/camltac
- Owner: epfl-systemf
- License: lgpl-2.1
- Created: 2026-05-16T14:34:14.000Z (about 1 month ago)
- Default Branch: main
- Last Pushed: 2026-06-08T11:26:26.000Z (8 days ago)
- Last Synced: 2026-06-08T13:19:27.327Z (8 days ago)
- Topics: ltac2, ocaml, rocq, rocq-prover
- Language: OCaml
- Homepage:
- Size: 288 KB
- Stars: 3
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Camltac: OCaml as a Tactic Language
Camltac allows OCaml to be written directly with Rocq scripts. It supports most constructs from Ltac2, including term construction (`constr:(…)`), pattern matching, and antiquotations using [`ppx_rocq`](https://github.com/epfl-systemf/ppx_rocq), and more. Moreover, Camltac ships with most of the [Ltac2 API](https://rocq-prover.org/doc/master/corelib/index.html#Ltac2), which guarantee stability across Rocq versions.
See the [quickstart](#quickstart) section for quick examples, or the [`examples`](./examples/) directory for more complete examples of using Camltac.
## Setup
To install Camltac from sources, clone the repo and run `opam install .`, as follows:
```sh
git clone git@github.com:epfl-systemf/camltac.git
cd camltac
opam install ./camltac.opam
# Optional: opam install ./camltac-examples.opam
```
Then, add `From Camltac Require Import Camltac.` to the top of your Rocq files, and you're ready to go!
## Quickstart
### Running OCaml code
The most primitive command provided by Camltac is `Camltac Run`, which runs an arbitrary OCaml snippet between parentheses or brackets:
```coq
From Camltac Require Import Camltac.
Camltac Run ocaml:{{ let _ = Feedback.msg_notice (Pp.str "Hello world!") }}.
(* Hello world! *)
```
Camltac also allows to define new modules, which can be used to reuse definitions:
```coq
Camltac Module M := ocaml:(let one = 1).
Camltac Run ocaml:{{
Feedback.msg_notice (Pp.int (M.one + M.one))
}}.
(* 2 *)
```
### Creating new tactics
To expose new tactics to Ltac2, use the `Ltac2.FFI` module:
```coq
From Ltac2 Require Import Ltac2.
Camltac Run ocaml:{{
let say_hello () =
Feedback.msg_notice (Pp.str "Hello from OCaml!")
let _ = Ltac2.FFI.(define "say_hello" (unit @-> ret unit) say_hello)
}}.
Ltac2 @external say_hello : unit -> unit := "camltac.plugin.runtime" "say_hello".
Ltac2 Eval say_hello (). (* Hello from OCaml! *)
```
Camltac can also run in tactic-in-term mode, similarly to `ltac:(…)` and `ltac2:(…)`:
```
Definition zero := ocaml:(let* z = {%constr| 0 |} in exact_no_check z).
Print zero.
(* zero = 0 : nat *)
```