Add Nix language support (#2781)

Mikayla Maki created 2 years ago

This adds rudimentary language support for the Nix expression language,
through tree-sitter-nix.

I spent a little bit of time trying to add support for one of the Nix
language servers too, but wasn't able to get any of them running
reliably without crashing, and so I've opted to stick to just the
tree-sitter grammar for now.


![image](https://github.com/zed-industries/zed/assets/285821/c770f3d8-6fa0-4083-9bf3-239cc78ca307)

Change summary

Cargo.lock                                  | 10 ++
Cargo.toml                                  |  1 
crates/zed/Cargo.toml                       |  1 
crates/zed/src/languages.rs                 |  2 
crates/zed/src/languages/nix/config.toml    | 11 ++
crates/zed/src/languages/nix/highlights.scm | 89 +++++++++++++++++++++++
6 files changed, 114 insertions(+)

Detailed changes

Cargo.lock

@@ -8387,6 +8387,15 @@ dependencies = [
  "tree-sitter",
 ]
 
+[[package]]
+name = "tree-sitter-nix"
+version = "0.0.1"
+source = "git+https://github.com/nix-community/tree-sitter-nix?rev=66e3e9ce9180ae08fc57372061006ef83f0abde7#66e3e9ce9180ae08fc57372061006ef83f0abde7"
+dependencies = [
+ "cc",
+ "tree-sitter",
+]
+
 [[package]]
 name = "tree-sitter-php"
 version = "0.19.1"
@@ -9933,6 +9942,7 @@ dependencies = [
  "tree-sitter-json 0.20.0",
  "tree-sitter-lua",
  "tree-sitter-markdown",
+ "tree-sitter-nix",
  "tree-sitter-php",
  "tree-sitter-python",
  "tree-sitter-racket",

Cargo.toml

@@ -131,6 +131,7 @@ tree-sitter-svelte = { git = "https://github.com/Himujjal/tree-sitter-svelte", r
 tree-sitter-racket = { git = "https://github.com/zed-industries/tree-sitter-racket", rev = "eb010cf2c674c6fd9a6316a84e28ef90190fe51a"}
 tree-sitter-yaml = { git = "https://github.com/zed-industries/tree-sitter-yaml", rev = "f545a41f57502e1b5ddf2a6668896c1b0620f930"}
 tree-sitter-lua = "0.0.14"
+tree-sitter-nix = { git = "https://github.com/nix-community/tree-sitter-nix", rev = "66e3e9ce9180ae08fc57372061006ef83f0abde7" }
 
 [patch.crates-io]
 tree-sitter = { git = "https://github.com/tree-sitter/tree-sitter", rev = "1c65ca24bc9a734ab70115188f465e12eecf224e" }

crates/zed/Cargo.toml

@@ -128,6 +128,7 @@ tree-sitter-svelte.workspace = true
 tree-sitter-racket.workspace = true
 tree-sitter-yaml.workspace = true
 tree-sitter-lua.workspace = true
+tree-sitter-nix.workspace = true
 
 url = "2.2"
 urlencoding = "2.1.2"

crates/zed/src/languages.rs

@@ -152,8 +152,10 @@ pub fn init(languages: Arc<LanguageRegistry>, node_runtime: Arc<NodeRuntime>) {
         tree_sitter_php::language(),
         vec![Arc::new(php::IntelephenseLspAdapter::new(node_runtime))],
     );
+
     language("elm", tree_sitter_elm::language(), vec![]);
     language("glsl", tree_sitter_glsl::language(), vec![]);
+    language("nix", tree_sitter_nix::language(), vec![]);
 }
 
 #[cfg(any(test, feature = "test-support"))]

crates/zed/src/languages/nix/config.toml

@@ -0,0 +1,11 @@
+name = "Nix"
+path_suffixes = ["nix"]
+line_comment = "# "
+block_comment = ["/* ", " */"]
+autoclose_before = ";:.,=}])>` \n\t\""
+brackets = [
+    { start = "{", end = "}", close = true, newline = true },
+    { start = "[", end = "]", close = true, newline = true },
+    { start = "(", end = ")", close = true, newline = true },
+    { start = "<", end = ">", close = true, newline = true },
+]

crates/zed/src/languages/nix/highlights.scm

@@ -0,0 +1,95 @@
+(comment) @comment
+
+[
+  "if"
+  "then"
+  "else"
+  "let"
+  "inherit"
+  "in"
+  "rec"
+  "with"
+  "assert"
+  "or"
+] @keyword
+
+[
+ (string_expression)
+ (indented_string_expression)
+] @string
+
+[
+  (path_expression)
+  (hpath_expression)
+  (spath_expression)
+] @string.special.path
+
+(uri_expression) @link_uri
+
+[
+  (integer_expression)
+  (float_expression)
+] @number
+
+(interpolation
+  "${" @punctuation.special
+  "}" @punctuation.special) @embedded
+
+(escape_sequence) @escape
+(dollar_escape) @escape
+
+(function_expression
+  universal: (identifier) @parameter
+)
+
+(formal
+  name: (identifier) @parameter
+  "?"? @punctuation.delimiter)
+
+(select_expression
+  attrpath: (attrpath (identifier)) @property)
+
+(apply_expression
+  function: [
+    (variable_expression (identifier)) @function
+    (select_expression
+      attrpath: (attrpath
+        attr: (identifier) @function .))])
+
+(unary_expression
+  operator: _ @operator)
+
+(binary_expression
+  operator: _ @operator)
+
+(variable_expression (identifier) @variable)
+
+(binding
+  attrpath: (attrpath (identifier)) @property)
+
+"=" @operator
+
+[
+  ";"
+  "."
+  ","
+] @punctuation.delimiter
+
+[
+  "("
+  ")"
+  "["
+  "]"
+  "{"
+  "}"
+] @punctuation.bracket
+
+(identifier) @variable
+
+((identifier) @function.builtin