Add scala syntax highlights (#1278)

* add partial scala syntax highlights

* ran cargo xtask docgen

* updated tree-sitter-scala, fixed highlights

* fix comments

* move identifier to the end of the highlights

* add indents

6 files changed, 237 insertions, 0 deletions

diff --git a/book/src/generated/lang-support.md b/book/src/generated/lang-support.md
index 80989e63..b7babd8c 100644
--- a/book/src/generated/lang-support.md
+++ b/book/src/generated/lang-support.md
@@ -31,6 +31,7 @@
 | racket |  |  |  | `racket` |
 | ruby | ✓ |  |  | `solargraph` |
 | rust | ✓ | ✓ | ✓ | `rust-analyzer` |
+| scala | ✓ |  |  | `metals` |
 | svelte | ✓ |  | ✓ | `svelteserver` |
 | toml | ✓ |  |  |  |
 | tsq | ✓ |  |  |  |
diff --git a/helix-syntax/languages/tree-sitter-scala b/helix-syntax/languages/tree-sitter-scala
-Subproject fb23ed9a99da012d86b7a5059b9d8928607cce2
+Subproject 0a3dd53a7fc4b352a538397d054380aaa28be54
diff --git a/languages.toml b/languages.toml
index abb94acf..88882f3e 100644
--- a/languages.toml
+++ b/languages.toml
@@ -430,3 +430,12 @@ file-types = ["md"]
 roots = []
 
 indent = { tab-width = 2, unit = "  " }
+
+[[language]]
+name = "scala"
+scope = "source.scala"
+roots = ["build.sbt"]
+file-types = ["scala", "sbt"]
+comment-token = "//"
+indent = { tab-width = 2, unit = "  " }
+language-server = { command = "metals" }
diff --git a/runtime/queries/scala/highlights.scm b/runtime/queries/scala/highlights.scm
new file mode 100644
index 00000000..50a6e18a
--- /dev/null
+++ b/runtime/queries/scala/highlights.scm
@@ -0,0 +1,203 @@
+; CREDITS @stumash (stuart.mashaal@gmail.com)
+
+;; variables
+
+
+((identifier) @variable.builtin
+ (#match? @variable.builtin "^this$"))
+
+(interpolation) @none
+
+; Assume other uppercase names constants.
+; NOTE: In order to distinguish constants we highlight
+; all the identifiers that are uppercased. But this solution
+; is not suitable for all occurrences e.g. it will highlight
+; an uppercased method as a constant if used with no params.
+; Introducing highlighting for those specific cases, is probably
+; best way to resolve the issue.
+((identifier) @constant (#match? @constant "^[A-Z]"))
+
+;; types
+
+(type_identifier) @type
+
+(class_definition
+  name: (identifier) @type)
+
+(object_definition
+  name: (identifier) @type)
+
+(trait_definition
+  name: (identifier) @type)
+
+(type_definition
+  name: (type_identifier) @type)
+
+; method definition
+
+(class_definition
+  body: (template_body
+    (function_definition
+      name: (identifier) @function.method)))
+(object_definition
+  body: (template_body
+    (function_definition
+      name: (identifier) @function.method)))
+(trait_definition
+  body: (template_body
+    (function_definition
+      name: (identifier) @function.method)))
+
+; imports
+
+(import_declaration
+  path: (identifier) @namespace)
+((stable_identifier (identifier) @namespace))
+
+((import_declaration
+  path: (identifier) @type) (#match? @type "^[A-Z]"))
+((stable_identifier (identifier) @type) (#match? @type "^[A-Z]"))
+
+((import_selectors (identifier) @type) (#match? @type "^[A-Z]"))
+
+; method invocation
+
+
+(call_expression
+  function: (identifier) @function)
+
+(call_expression
+  function: (field_expression
+    field: (identifier) @function.method))
+
+((call_expression
+   function: (identifier) @variable.other.member)
+ (#match? @variable.other.member "^[A-Z]"))
+
+(generic_function
+  function: (identifier) @function)
+
+(
+  (identifier) @function.builtin
+  (#match? @function.builtin "^super$")
+)
+
+; function definitions
+
+(function_definition
+  name: (identifier) @function)
+
+(parameter
+  name: (identifier) @variable.parameter)
+
+; expressions
+
+
+(field_expression field: (identifier) @variable.other.member)
+(field_expression value: (identifier) @type
+ (#match? @type "^[A-Z]"))
+
+(infix_expression operator: (identifier) @operator)
+(infix_expression operator: (operator_identifier) @operator)
+(infix_type operator: (operator_identifier) @operator)
+(infix_type operator: (operator_identifier) @operator)
+
+; literals
+(boolean_literal) @constant.builtin.boolean
+(integer_literal) @constant.numeric.integer
+(floating_point_literal) @constant.numeric.float
+
+
+(symbol_literal) @string.special.symbol
+ 
+[
+(string)
+(character_literal)
+(interpolated_string_expression)
+] @string
+
+(interpolation "$" @punctuation.special)
+
+;; keywords
+
+[
+  "abstract"
+  "case"
+  "class"
+  "extends"
+  "final"
+  "finally"
+;; `forSome` existential types not implemented yet
+  "implicit"
+  "lazy"
+;; `macro` not implemented yet
+  "object"
+  "override"
+  "package"
+  "private"
+  "protected"
+  "sealed"
+  "trait"
+  "type"
+  "val"
+  "var"
+  "with"
+] @keyword
+
+(null_literal) @constant.builtin
+(wildcard) @keyword
+
+;; special keywords
+
+"new" @keyword.operator
+
+[
+ "else"
+ "if"
+ "match"
+ "try"
+ "catch"
+ "throw"
+] @keyword.control.conditional
+
+[
+ "("
+ ")"
+ "["
+ "]"
+ "{"
+ "}"
+] @punctuation.bracket
+
+[
+ "."
+ ","
+] @punctuation.delimiter
+
+[
+ "do"
+ "for"
+ "while"
+ "yield"
+] @keyword.control.repeat
+
+"def" @keyword.function
+
+[
+  "=>"
+  "<-"
+  "@"
+] @keyword.operator
+
+"import" @keyword.control.import
+
+"return" @keyword.control.return
+
+(comment) @comment
+
+;; `case` is a conditional keyword in case_block
+
+(case_block
+  (case_clause ("case") @keyword.control.conditional))
+
+(identifier) @variable
\ No newline at end of file
diff --git a/runtime/queries/scala/indents.toml b/runtime/queries/scala/indents.toml
new file mode 100644
index 00000000..6de54844
--- /dev/null
+++ b/runtime/queries/scala/indents.toml
@@ -0,0 +1,23 @@
+
+indent = [
+ "block",
+ "arguments",
+ "parameter",
+ "class_definition",
+ "trait_definition",
+ "object_definition",
+ "function_definition",
+ "val_definition",
+ "import_declaration",
+ "while_expression",
+ "do_while_expression",
+ "for_expression",
+ "try_expression",
+ "match_expression"
+]
+
+outdent = [
+ "}",
+ "]",
+ ")"
+]
diff --git a/runtime/queries/scala/injections.scm b/runtime/queries/scala/injections.scm
new file mode 100644
index 00000000..4bb7d675
--- /dev/null
+++ b/runtime/queries/scala/injections.scm
@@ -0,0 +1 @@
+(comment) @comment