ocamlPackages.sedlex_2: 2.1 -> 2.2

* use dune 2
* refactor fetching of dependencies (reduce duplication)
* remove dune rule for data files before building since dune 2 doesn't
  like the symlinked data files if the rule is present

pkgs/development/ocaml-modules/sedlex/2.nix

@@ -14,35 +14,41 @@ then throw "sedlex is not available for OCaml ${ocaml.version}"
 else
 
 let
+  unicodeVersion = "12.1.0";
+  baseUrl = "https://www.unicode.org/Public/${unicodeVersion}";
+
   DerivedCoreProperties = fetchurl {
-    url = "https://www.unicode.org/Public/12.1.0/ucd/DerivedCoreProperties.txt";
+    url = "${baseUrl}/ucd/DerivedCoreProperties.txt";
     sha256 = "0s6sn1yr9qmb2i6gf8dir2zpsbjv1frdfzy3i2yjylzvf637msx6";
   };
   DerivedGeneralCategory = fetchurl {
-    url = "https://www.unicode.org/Public/12.1.0/ucd/extracted/DerivedGeneralCategory.txt";
+    url = "${baseUrl}/ucd/extracted/DerivedGeneralCategory.txt";
     sha256 = "1rifzq9ba6c58dn0lrmcb5l5k4ksx3zsdkira3m5p6h4i2wriy3q";
   };
   PropList = fetchurl {
-    url = "https://www.unicode.org/Public/12.1.0/ucd/PropList.txt";
+    url = "${baseUrl}/ucd/PropList.txt";
     sha256 = "0gsb1jpj3mnqbjgbavi4l95gl6g4agq58j82km22fdfg63j3w3fk";
   };
 in
 buildDunePackage rec {
   pname = "sedlex";
-  version = "2.1";
+  version = "2.2";
+
+  useDune2 = true;
 
   src = fetchFromGitHub {
     owner = "ocaml-community";
     repo = "sedlex";
     rev = "v${version}";
-    sha256 = "05f6qa8x3vhpdz1fcnpqk37fpnyyq13icqsk2gww5idjnh6kng26";
+    sha256 = "18dwl2is5j26z6b1c47b81wvcpxw44fasppdadsrs9vsw63rwcm3";
   };
 
   propagatedBuildInputs = [
     gen uchar ocaml-migrate-parsetree ppx_tools_versioned
   ];
 
   preBuild = ''
+    rm src/generator/data/dune
     ln -s ${DerivedCoreProperties} src/generator/data/DerivedCoreProperties.txt
     ln -s ${DerivedGeneralCategory} src/generator/data/DerivedGeneralCategory.txt
     ln -s ${PropList} src/generator/data/PropList.txt