Fix Nix and convert to flakes

.nix/packages.nix

@@ -0,0 +1,19 @@
+{ ocamlPackages, fetchurl }:
+
+ocamlPackages.overrideScope' (self: super: {
+  cmdliner_1_1_0 = super.cmdliner.overrideAttrs (o: rec {
+    version = "1.1.0";
+    src = fetchurl {
+      url = "https://erratique.ch/software/${o.pname}/releases/${o.pname }-${version}.tbz";
+      sha256 = "sha256-irWd4HTlJSYuz3HMgi1de2GVL2qus0QjeCe1WdsSs8Q=";
+    };
+  });
+  alcotest = (super.alcotest.override {
+    cmdliner = self.cmdliner_1_1_0;
+  }).overrideAttrs (_: {
+    doCheck = false;
+  });
+  bindlib = ocamlPackages.callPackage ./bindlib.nix { };
+  unionfind = ocamlPackages.callPackage ./unionfind.nix { };
+  ppx_yojson_conv = ocamlPackages.callPackage ./ppx_yojson_conv.nix { };
+})

.nix/ppx_yojson_conv.nix

@@ -0,0 +1,20 @@
+{ lib, fetchurl, buildDunePackage, ppxlib, ppx_yojson_conv_lib, ppx_js_style }:
+
+buildDunePackage rec {
+  pname = "ppx_yojson_conv";
+  version = "0.14.0";
+
+  minimumOCamlVersion = "4.0.8";
+
+  useDune2 = true;
+
+  propagatedBuildInputs = [
+    ppxlib ppx_yojson_conv_lib ppx_js_style
+  ];
+
+  src = fetchurl
+    {
+      url = "https://ocaml.janestreet.com/ocaml-core/v0.14/files/ppx_yojson_conv-v0.14.0.tar.gz";
+      sha256 = "0ls6vzj7k0wrjliifqczs78anbc8b88as5w7a3wixfcs1gjfsp2w";
+    };
+}

default.nix

@@ -7,7 +7,7 @@
 , menhir
 , unionfind
 , bindlib
-, cmdliner
+, cmdliner_1_1_0
 , re
 , zarith
 , zarith_stubs_js
@@ -22,12 +22,13 @@
 , ppx_deriving
 , z3
 , alcotest
+, ppx_yojson_conv
 , menhirLib ? null #for nixos-unstable compatibility.
 }:
 
 buildDunePackage rec {
   pname = "catala";
-  version = "0.5.0";
+  version = "0.6.0"; # TODO parse `catala.opam` with opam2json
 
   minimumOCamlVersion = "4.11";
 
@@ -40,7 +41,7 @@ buildDunePackage rec {
     sedlex_2
     menhir
     menhirLib
-    cmdliner
+    cmdliner_1_1_0
     re
     zarith
     zarith_stubs_js
@@ -50,6 +51,7 @@ buildDunePackage rec {
     benchmark
     js_of_ocaml
     js_of_ocaml-ppx
+    ppx_yojson_conv
     camomile
     cppo
     z3
@@ -65,8 +67,6 @@ buildDunePackage rec {
   ] ++ (if isNull menhirLib then [ ] else [ menhirLib ]);
   doCheck = true;
 
-  patches = [ ./.nix/no-web.patch ];
-
   meta = with lib; {
     homepage = "https://catala-lang.org";
     description =

flake.nix

@@ -0,0 +1,33 @@
+{
+  inputs = {
+    flake-utils.url = github:numtide/flake-utils;
+    nixpkgs.url = github:NixOS/nixpkgs/nixos-unstable;
+  };
+
+  outputs = {nixpkgs, flake-utils, ...}:
+    let
+      systems = [ "x86_64-linux" ];
+    in flake-utils.lib.eachSystem systems (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+        ocamlPackages = pkgs.callPackage ./.nix/packages.nix {};
+      in
+        rec {
+          packages = {
+            catala = ocamlPackages.callPackage ./. {};
+          };
+          defaultPackage = packages.catala;
+          devShell = pkgs.mkShell {
+            inputsFrom = [packages.catala];
+            buildInputs = [
+              pkgs.inotify-tools
+              ocamlPackages.merlin
+              pkgs.ocamlformat
+              ocamlPackages.ocp-indent
+              ocamlPackages.utop
+              ocamlPackages.ocaml-lsp
+            ];
+          };
+        }
+    );
+}