helix/runtime/queries/nix/highlights.scm

; tree-sitter highlighting resolves in .scm order. For a given byte
; offset, the last matching capture wins. This file is ordered from
; generic to specific: base variables and keywords first, then more
; targeted builtin / call / member patterns that override them.

; Base ----------------------------------------------------------------

; Generic identifier reference. Specific rules (builtins, calls,
; booleans, constants) later in the file override this.
(variable_expression (identifier) @variable)

; Comments ------------------------------------------------------------

(comment) @comment
(doc_comment) @comment.line.documentation

; Keywords ------------------------------------------------------------

[
  "assert"
  "in"
  "inherit"
  "let"
  "rec"
  "with"
] @keyword

[
  "if"
  "then"
  "else"
] @keyword.control.conditional

"or" @keyword.operator

; Literals ------------------------------------------------------------

(integer_expression) @constant.numeric.integer
(float_expression) @constant.numeric.float

[
  (string_expression)
  (indented_string_expression)
] @string

(escape_sequence) @constant.character.escape
(dollar_escape) @constant.character.escape

[
  (path_expression)
  (hpath_expression)
  (spath_expression)
] @string.special.path

(uri_expression) @string.special.url

; Functions -----------------------------------------------------------

; Parameters: `x: body` and `{ a, b }: body`.
(function_expression
  universal: (identifier) @variable.parameter)

(formal
  name: (identifier) @variable.parameter
  "?"? @punctuation.delimiter)

(ellipses) @variable.parameter.builtin

; Attrset members -----------------------------------------------------

(binding
  attrpath: (attrpath (identifier)) @variable.other.member)

(select_expression
  attrpath: (attrpath (identifier)) @variable.other.member)

(inherit attrs: (inherited_attrs attr: (identifier) @variable.other.member))
(inherit_from attrs: (inherited_attrs attr: (identifier) @variable.other.member))

; Function calls ------------------------------------------------------
; After member rules so `lib.isBool` in apply position is @function,
; not @variable.other.member.

(apply_expression
  function: [
    (variable_expression (identifier) @function)
    (select_expression
      attrpath: (attrpath
        attr: (identifier) @function .))])

; Function-valued arguments of Nix builtins and nixpkgs lib functions.
; Applications are left-associative, so each argument position has a
; differently nested `apply_expression`.
((apply_expression
  function: [
    (variable_expression (identifier) @_higher_order @function)
    (select_expression
      attrpath: (attrpath
        attr: (identifier) @_higher_order @function .))]
  argument: [
    (variable_expression (identifier) @function)
    (select_expression
      attrpath: (attrpath
        attr: (identifier) @function .))])
 (#any-of? @_higher_order
   "all" "any" "collect" "compareLists" "composeExtensions" "concatImapStrings"
   "concatMap" "concatMapAttrs" "concatMapStrings" "converge" "count" "crossLists"
   "extends" "filter" "filterAttrs" "filterAttrsRecursive" "filterSource" "findFirst"
   "findFirstIndex" "findSingle" "fix" "fix'" "flip" "fold" "foldAttrs" "foldl"
   "foldl'" "foldlAttrs" "foldr" "functionArgs" "genList" "groupBy" "groupBy'"
   "ifilter0" "imap0" "imap1" "makeExtensible" "makeOverridable" "makeScope"
   "makeScopeWithSplicing" "map" "mapAttrs" "mapAttrs'" "mapAttrsRecursive"
   "mapAttrsRecursiveCond" "mapAttrsToList" "mapAttrsToListRecursive"
   "mapAttrsToListRecursiveCond" "mapCartesianProduct" "mapCrossIndex" "mapDerivationAttrset"
   "mapNullable" "mirrorFunctionArgs" "mkAliasAndWrapDefinitions" "optionDescriptionPhrase"
   "partition" "recursiveUpdateUntil"
   "setFunctionArgs" "sort" "sortOn" "splitByAndCompare" "splitStringBy" "stringAsChars"
   "toposort" "traceValFn" "traceValSeqFn" "traceValSeqNFn" "updateName"
   "zipAttrsWith" "zipListsWith"))

((apply_expression
  function: (apply_expression
    function: [
      (variable_expression (identifier) @_higher_order @function)
      (select_expression
        attrpath: (attrpath
          attr: (identifier) @_higher_order @function .))])
  argument: [
    (variable_expression (identifier) @function)
    (select_expression
      attrpath: (attrpath
        attr: (identifier) @function .))])
 (#any-of? @_higher_order
   "addCheck" "coercedTo" "composeExtensions" "concatImapStringsSep"
   "concatMapAttrsStringSep" "concatMapStringsSep" "extends" "forEach" "genAttrs"
   "genAttrs'" "listDfs" "makeExtensibleWithCustomName" "makeScope"
   "makeScopeWithSplicing" "mapAttrsRecursiveCond" "mapAttrsToListRecursiveCond"
   "mirrorFunctionArgs" "mkDerivedConfig" "overrideDerivation" "splitByAndCompare"
   "zipAttrsWithNames"))

((apply_expression
  function: (apply_expression
    function: (apply_expression
      function: [
        (variable_expression (identifier) @_higher_order @function)
        (select_expression
          attrpath: (attrpath
            attr: (identifier) @_higher_order @function .))]))
  argument: [
    (variable_expression (identifier) @function)
    (select_expression
      attrpath: (attrpath
        attr: (identifier) @function .))])
 (#any-of? @_higher_order
   "groupBy'" "mkChangedOptionModule" "mkMergedOptionModule" "splitByAndCompare"
   "traceFnSeqN"))

; Pipe operators evaluate the side pointed to by the operator as a function:
; `value |> lib.foo` and `lib.foo <| value`.
(binary_expression
  operator: "|>"
  right: [
    (variable_expression (identifier) @function)
    (select_expression
      attrpath: (attrpath
        attr: (identifier) @function .))])

(binary_expression
  left: [
    (variable_expression (identifier) @function)
    (select_expression
      attrpath: (attrpath
        attr: (identifier) @function .))]
  operator: "<|")

(binding
  attrpath: (attrpath
    attr: (identifier) @function)
  expression: (function_expression))

; Builtins ------------------------------------------------------------

; `builtins.*` method-style calls: highlight the attr as a builtin
; function. `builtins` itself is painted by the @constant.builtin rule
; further down.
((select_expression
  expression: (variable_expression
    name: (identifier) @_id)
  attrpath: (attrpath
    attr: (identifier) @function.builtin))
 (#eq? @_id "builtins"))

; In apply position: `map f xs` -> `map` is a function builtin.
((apply_expression
  function: (variable_expression
    (identifier) @function.builtin))
 (#match? @function.builtin "^(__add|__addDrvOutputDependencies|__addErrorContext|__all|__any|__appendContext|__attrNames|__attrValues|__bitAnd|__bitOr|__bitXor|__catAttrs|__ceil|__compareVersions|__concatLists|__concatMap|__concatStringsSep|__convertHash|__deepSeq|__div|__elem|__elemAt|__fetchurl|__filter|__filterSource|__findFile|__flakeRefToString|__floor|__foldl'|__fromJSON|__functionArgs|__genList|__genericClosure|__getAttr|__getContext|__getEnv|__getFlake|__groupBy|__hasAttr|__hasContext|__hashFile|__hashString|__head|__intersectAttrs|__isAttrs|__isBool|__isFloat|__isFunction|__isInt|__isList|__isPath|__isString|__length|__lessThan|__listToAttrs|__mapAttrs|__match|__mul|__parseDrvName|__parseFlakeRef|__partition|__path|__pathExists|__readDir|__readFile|__readFileType|__replaceStrings|__seq|__sort|__split|__splitVersion|__storePath|__stringLength|__sub|__substring|__tail|__toFile|__toJSON|__toPath|__toXML|__trace|__traceVerbose|__tryEval|__typeOf|__unsafeDiscardOutputDependency|__unsafeDiscardStringContext|__unsafeGetAttrPos|__warn|__zipAttrsWith|baseNameOf|break|derivation|derivationStrict|dirOf|fetchGit|fetchMercurial|fetchTarball|fetchTree|fromTOML|isNull|map|placeholder|removeAttrs|scopedImport|toString)$"))

; `import` behaves like a keyword.
((variable_expression (identifier) @keyword.control.import)
 (#eq? @keyword.control.import "import"))

; `abort` / `throw` are control-flow exceptions.
((variable_expression (identifier) @keyword.control.exception)
 (#any-of? @keyword.control.exception "abort" "throw"))

; Booleans / constants ------------------------------------------------

((variable_expression (identifier) @constant.builtin.boolean)
 (#any-of? @constant.builtin.boolean "true" "false"))

((variable_expression (identifier) @constant.builtin)
 (#any-of? @constant.builtin
   "builtins" "null"
   "__curPos" "__currentSystem" "__currentTime" "__langVersion"
   "__nixPath" "__nixVersion" "__storeDir"))

; Operators -----------------------------------------------------------

(unary_expression
  operator: _ @operator)

(binary_expression
  operator: _ @operator)

[
  "="
  "@"
] @operator

; Punctuation ---------------------------------------------------------

[
  ";"
  "."
  ","
  ":"
] @punctuation.delimiter

[
  "("
  ")"
  "["
  "]"
  "{"
  "}"
] @punctuation.bracket

(interpolation
  "${" @punctuation.special
  "}" @punctuation.special) @embedded

(has_attr_expression
  expression: (_)
  "?" @operator
  attrpath: (attrpath
    attr: (identifier) @variable.other.member))