Add Rust queries (#57)

* queries(rust): add highlight query.

Also slightly changes the way constructors are highlighted.

* highglight(rust): use new query syntax

queries/rust/highlights.scm

@@ -0,0 +1,167 @@
+; Forked from https://github.com/tree-sitter/tree-sitter-rust
+; Copyright (c) 2017 Maxim Sokolov
+; Licensed under the MIT license.
+
+; Identifier conventions
+
+; Assume all-caps names are constants
+((identifier) @constant
+ (#match? @constant "^[A-Z][A-Z\\d_]+$'"))
+
+; Other identifiers
+
+(type_identifier) @type
+(primitive_type) @type.builtin
+(field_identifier) @field
+
+
+; Function calls
+(call_expression
+  function: (identifier) @function)
+(call_expression
+  function: (field_expression
+    field: (field_identifier) @function))
+
+(generic_function
+  function: (identifier) @function)
+(generic_function
+  function: (scoped_identifier
+    name: (identifier) @function))
+(generic_function
+  function: (field_expression
+    field: (field_identifier) @function))
+
+; Assume other uppercase names are enum constructors
+([(identifier) (field_identifier)] @constant
+ (#match? @constant "^[A-Z]"))
+
+; Assume that uppercase names in paths are types
+((scoped_identifier
+  path: (identifier) @type)
+ (#match? @type "^[A-Z]"))
+((scoped_identifier
+    name: (identifier) @type)
+ (#match? @type "^[A-Z]"))
+
+;; Correct enum constructors
+(call_expression
+  function: (scoped_identifier
+    "::"
+    name: (identifier) @constant)
+  (#match? @constant "^[A-Z]"))
+
+;; Assume that all `#[derive]` arguments are types
+(meta_item
+  (identifier) @meta
+  arguments: (meta_arguments (meta_item (identifier) @type))
+  (#eq? @meta "derive"))
+
+(macro_invocation
+  macro: (identifier) @function.macro
+  "!" @function.macro)
+
+; Function definitions
+
+(function_item (identifier) @function)
+(function_signature_item (identifier) @function)
+
+[
+(line_comment)
+(block_comment)
+ ] @comment
+
+[
+"("
+")"
+"["
+"]"
+ ] @punctuation.bracket
+
+(type_arguments
+  "<" @punctuation.bracket
+  ">" @punctuation.bracket)
+(type_parameters
+  "<" @punctuation.bracket
+  ">" @punctuation.bracket)
+
+[
+"::"
+"."
+";"
+ ] @punctuation.delimiter
+
+(parameter (identifier) @parameter)
+
+(lifetime (identifier) @label)
+
+(self) @variable.builtin
+
+[
+"break"
+"const"
+"default"
+"dyn"
+"enum"
+"extern"
+"fn"
+"impl"
+"let"
+"macro_rules!"
+"match"
+"mod"
+"move"
+"pub"
+"ref"
+"return"
+"static"
+"struct"
+"trait"
+"type"
+"union"
+"unsafe"
+"use"
+"where"
+(mutable_specifier)
+(super)
+; TODO(vigoux): attribute items should have some kind of injections
+(attribute_item)
+(inner_attribute_item)
+ ] @keyword
+
+(use_list (self) @keyword)
+(scoped_use_list (self) @keyword)
+(scoped_identifier (self) @keyword)
+
+[
+"continue"
+"else"
+"if"
+] @conditional
+
+[
+"for"
+"in"
+"loop"
+"while"
+] @repeat
+
+[
+(char_literal)
+(string_literal)
+(raw_string_literal)
+] @string
+
+(boolean_literal) @boolean
+(integer_literal) @number
+(float_literal) @float
+
+(escape_sequence) @string.escape
+
+[
+"as"
+"*"
+"&"
+"'"
+ ] @operator
+
+(closure_parameters "|" @operator "|" @operator)