Add support for Nix

Closes #196

CHANGELOG.md

@@ -15,8 +15,7 @@ syntactic changes".
 Fixed an issue in C and C++ where blank lines were highlighted after
 novel preprocessor lines.
 
-Added support for Janet.
-Added support for Lua.
+Added support for Janet, Lua and Nix.
 
 ## 0.24 (release 26th March 2022)
 

README.md

@@ -55,6 +55,7 @@ Difftastic supports the following languages:
 * JavaScript (and JSX)
 * JSON
 * Lua
+* Nix
 * OCaml
 * PHP
 * Python

build.rs

@@ -139,6 +139,11 @@ fn main() {
             src_dir: "vendor/tree-sitter-lua-src",
             extra_files: vec!["scanner.cc"],
         },
+        TreeSitterParser {
+            name: "tree-sitter-nix",
+            src_dir: "vendor/tree-sitter-nix-src",
+            extra_files: vec!["scanner.c"],
+        },
         TreeSitterParser {
             name: "tree-sitter-ocaml",
             src_dir: "vendor/tree-sitter-ocaml-src/ocaml/src",

manual/src/upstream_parsers.md

@@ -21,6 +21,7 @@ Difftastic uses the following tree-sitter parsers:
 | JavaScript, JSX | [tree-sitter/tree-sitter-javascript](https://github.com/tree-sitter/tree-sitter-javascript)                                             |
 | JSON            | [tree-sitter/tree-sitter-json](https://github.com/tree-sitter/tree-sitter-json)                                                         |
 | Lua             | [nvim-treesitter/tree-sitter-lua](https://github.com/nvim-treesitter/tree-sitter-lua)                                                   |
+| Nix             | [cstrahan/tree-sitter-nix](https://github.com/cstrahan/tree-sitter-nix)                                                                 |
 | OCaml           | [tree-sitter/tree-sitter-ocaml](https://github.com/tree-sitter/tree-sitter-ocaml)                                                       |
 | PHP             | [tree-sitter/tree-sitter-php](https://github.com/tree-sitter/tree-sitter-php)                                                           |
 | Python          | [tree-sitter/tree-sitter-python](https://github.com/tree-sitter/tree-sitter-python)                                                     |

sample_files/compare.expected

@@ -85,6 +85,9 @@ sample_files/nest_before.rs sample_files/nest_after.rs
 sample_files/nesting_before.el sample_files/nesting_after.el
 6af3112dad0de540b4104655119970e8  -
 
+sample_files/nix_before.nix sample_files/nix_after.nix
+2f8e64ce28f4067210e9f12f10cb4579  -
+
 sample_files/ocaml_before.ml sample_files/ocaml_after.ml
 2e415fe09d7cee050f8143a8d8c209bd  -
 

sample_files/nix_after.nix

@@ -0,0 +1,24 @@
+{ lib, fetchFromGitHub, rustPlatform, tree-sitter }:
+
+rustPlatform.buildRustPackage rec {
+  pname = "difftastic";
+  version = "0.24.0";
+
+  src = fetchFromGitHub {
+    owner = "wilfred";
+    repo = pname;
+    rev = version;
+    sha256 = "sha256-Yp0WwzGo8nuRZuiHdUPxPM1SYBeeVA3SMDfHnQmqUqY=";
+  };
+
+  cargoSha256 = "sha256-m80PT2UQYhA5KEh7ax/fhh6vuse0DXhbFsh2x4pwkWY=";
+
+  meta = with lib; {
+    description = "A syntax-aware diff";
+    homepage = "https://github.com/Wilfred/difftastic";
+    changelog = "https://github.com/Wilfred/difftastic/raw/${version}/CHANGELOG.md";
+    license = licenses.mit;
+    maintainers = with maintainers; [ ethancedwards8 figsoda ];
+    mainProgram = "difft";
+  };
+}

sample_files/nix_before.nix

@@ -0,0 +1,35 @@
+{ lib, fetchFromGitHub, rustPlatform, tree-sitter }:
+
+rustPlatform.buildRustPackage rec {
+  pname = "difftastic";
+  version = "0.12.0";
+
+  src = fetchFromGitHub {
+    owner = "wilfred";
+    repo = pname;
+    rev = version;
+    sha256 = "sha256-A6Z3g6fbYBynyN4OhRrZNO0ZghvT3XnIahdUQ8SE8tU=";
+  };
+
+  cargoSha256 = "sha256-6/JwrPymtpj/CXqx3Pe43v+MJTNONArU2WEo/zgJhT4=";
+
+  postPatch = ''
+    pushd vendor
+    for grammar in */; do
+      if [ -d "${tree-sitter.grammars}/$grammar" ]; then
+        rm -r "$grammar"
+        ln -s "${tree-sitter.grammars}/$grammar"
+      fi
+    done
+    popd
+  '';
+
+  meta = with lib; {
+    description = "A syntax-aware diff";
+    homepage = "https://github.com/Wilfred/difftastic";
+    changelog = "https://github.com/Wilfred/difftastic/raw/${version}/CHANGELOG.md";
+    license = licenses.mit;
+    maintainers = with maintainers; [ ethancedwards8 figsoda ];
+    mainProgram = "difft";
+  };
+}

src/guess_language.rs

@@ -36,6 +36,7 @@ pub enum Language {
     Json,
     Jsx,
     Lua,
+    Nix,
     OCaml,
     OCamlInterface,
     Php,
@@ -197,6 +198,7 @@ fn from_extension(extension: &OsStr, src: &str) -> Option<Language> {
         "jsx" => Some(Jsx),
         "json" => Some(Json),
         "lua" => Some(Lua),
+        "nix" => Some(Nix),
         "ml" => Some(OCaml),
         "mli" => Some(OCamlInterface),
         "php" if !src.starts_with("<?hh") => Some(Php),

src/tree_sitter_parser.rs

@@ -60,6 +60,7 @@ extern "C" {
     fn tree_sitter_javascript() -> ts::Language;
     fn tree_sitter_json() -> ts::Language;
     fn tree_sitter_lua() -> ts::Language;
+    fn tree_sitter_nix() -> ts::Language;
     fn tree_sitter_ocaml() -> ts::Language;
     fn tree_sitter_ocaml_interface() -> ts::Language;
     fn tree_sitter_php() -> ts::Language;
@@ -366,6 +367,22 @@ pub fn from_language(language: guess::Language) -> TreeSitterConfig {
                 .unwrap(),
             }
         }
+        Nix => {
+            let language = unsafe { tree_sitter_nix() };
+            TreeSitterConfig {
+                name: "Nix",
+                language,
+                atom_nodes: vec!["string_expression", "indented_string_expression"]
+                    .into_iter()
+                    .collect(),
+                delimiter_tokens: vec![("{", "}"), ("[", "]")].into_iter().collect(),
+                highlight_query: ts::Query::new(
+                    language,
+                    include_str!("../vendor/highlights/nix.scm"),
+                )
+                .unwrap(),
+            }
+        }
         OCaml => {
             let language = unsafe { tree_sitter_ocaml() };
             TreeSitterConfig {

vendor/highlights/nix.scm

@@ -0,0 +1 @@
+../tree-sitter-nix/queries/highlights.scm

vendor/tree-sitter-nix-src

@@ -0,0 +1 @@
+tree-sitter-nix/src