Fix 'nix flake check'

Turns out that 'tree-sitter' is not wrapped to have node and a compiler
available, because nixpkgs assumes that grammars already include
generated files.

So wrap it manually and use that in our pre-commit/checks.

.drone.yml

@@ -0,0 +1,31 @@
+---
+kind: pipeline
+type: exec
+name: abacus checks
+
+steps:
+- name: flake check
+  commands:
+  - nix flake check
+
+- name: package check
+  commands:
+  - nix build
+
+- name: notifiy
+  commands:
+  - nix run github:ambroisie/matrix-notifier
+  environment:
+    ADDRESS:
+      from_secret: matrix_homeserver
+    ROOM:
+      from_secret: matrix_roomid
+    USER:
+      from_secret: matrix_username
+    PASS:
+      from_secret: matrix_password
+  when:
+    status:
+      - failure
+      - success
+...

flake.nix

@@ -34,14 +34,45 @@
     , nixpkgs
     , pre-commit-hooks
     }:
-    flake-utils.lib.eachDefaultSystem
+    let
+      inherit (flake-utils.lib) eachSystem system;
+
+      mySystems = [
+        system.aarch64-darwin
+        system.aarch64-linux
+        system.x86_64-darwin
+        system.x86_64-linux
+      ];
+
+      eachMySystem = eachSystem mySystems;
+    in
+    eachMySystem
       (system:
       let
         pkgs = import nixpkgs {
           inherit system;
+          overlays = [ self.overlays.default ];
         };
 
-        version = (builtins.fromJSON (builtins.readFile ./package.json)).version;
+        tree-sitter-env = pkgs.stdenv.mkDerivation {
+          name = "tree-sitter-env";
+
+          nativeBuildInputs = with pkgs; [
+            makeWrapper
+          ];
+
+          dontUnpack = true;
+
+          dontBuild = true;
+
+          installPhase = ''
+            mkdir -p $out/bin
+            makeWrapper \
+              ${pkgs.tree-sitter}/bin/tree-sitter \
+              $out/bin/tree-sitter \
+              --prefix PATH : "${with pkgs; lib.makeBinPath [stdenv.cc nodejs]}"
+          '';
+        };
       in
       rec {
         checks = {
@@ -66,14 +97,14 @@
               tree-sitter = {
                 enable = true;
                 name = "tree-sitter tests";
-                entry = "${pkgs.tree-sitter}/bin/tree-sitter test";
+                entry = "${tree-sitter-env}/bin/tree-sitter test";
                 pass_filenames = false;
               };
 
               tree-sitter-files = {
                 enable = true;
                 name = "tree-sitter generated files";
-                entry = "${pkgs.tree-sitter}/bin/tree-sitter generate";
+                entry = "${tree-sitter-env}/bin/tree-sitter generate";
                 pass_filenames = false;
               };
             };
@@ -92,14 +123,23 @@
         };
 
         packages = {
-          default =
-            let mkGrammar = pkgs.callPackage "${nixpkgs}/pkgs/development/tools/parsing/tree-sitter/grammar.nix" { };
-            in
-            mkGrammar {
-              language = "tiger";
-              inherit version;
-              source = ./.;
-            };
+          default = packages.tree-sitter-tiger;
+
+          inherit (pkgs.tree-sitter.passthru.builtGrammars) tree-sitter-tiger;
+
+          inherit (pkgs) tree-sitter;
         };
-      });
+      }) // {
+      overlays = {
+        default = final: prev: {
+          tree-sitter = prev.tree-sitter.override {
+            extraGrammars = {
+              tree-sitter-tiger = {
+                src = ./.;
+              };
+            };
+          };
+        };
+      };
+    };
 }

queries/highlights.scm

@@ -33,6 +33,7 @@
 (nil_literal) @constant.builtin
 (integer_literal) @number
 (string_literal) @string
+(escape_sequence) @string.escape
 ; }}}
 
 ; Operators {{{

test/highlight/literals.tig

@@ -2,5 +2,7 @@ nil
 /* <- constant.builtin */
 42
 /* <- number */
-"Hello World!"
-/* <- string */
+"Hello World!\n"
+/* <- string
+             ^ string.escape
+*/