From e09db29aa47a0dfa386b262352391c2496e56676 Mon Sep 17 00:00:00 2001
From: Alain <alain@inria.fr>
Date: Mon, 29 Nov 2021 11:24:03 +0100
Subject: [PATCH] add a check to whenever menhirLib exists

If it does, it add menhirLib as a dependency. Else, ignore it.
---
 default.nix | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/default.nix b/default.nix
index f6450c4f..fef100e2 100644
--- a/default.nix
+++ b/default.nix
@@ -1,6 +1,25 @@
-{ lib, fetchFromGitHub, buildDunePackage, ansiterminal, sedlex_2, menhir
-, menhirLib, unionfind, bindlib, cmdliner, re, zarith, zarith_stubs_js, ocamlgraph
-, calendar, visitors, benchmark, js_of_ocaml, js_of_ocaml-ppx, camomile, cppo }:
+{ lib
+, fetchFromGitHub
+, buildDunePackage
+, ansiterminal
+, sedlex_2
+, menhir
+, unionfind
+, bindlib
+, cmdliner
+, re
+, zarith
+, zarith_stubs_js
+, ocamlgraph
+, calendar
+, visitors
+, benchmark
+, js_of_ocaml
+, js_of_ocaml-ppx
+, camomile
+, cppo
+, menhirLib ? null #for nixos-unstable compatibility.
+}:
 
 buildDunePackage rec {
   pname = "catala";
@@ -32,7 +51,7 @@ buildDunePackage rec {
 
     unionfind
     bindlib
-  ];
+  ] ++ (if isNull menhirLib then [ ] else [ menhirLib ]);
   doCheck = true;
 
   patches = [ ./.nix/no-web.patch ];
@@ -44,4 +63,4 @@ buildDunePackage rec {
     license = licenses.asl20;
     maintainers = with maintainers; [ ];
   };
-}
+}
\ No newline at end of file