Added USD as a language + some queries

Added USD highlight unittests

Added USD indentation

Added USD indents.scm file

Added USD indent rules

Simplified USD highlight groups

Added explicit highlight groups

Added newline

Removed after/ftdetect/usda.lua

usd/indents.scm - Added inline comments explaining the nodes

Fixed USD highlight group unittests

Added indentation unittests

Simplified USD `@identifier` highlighting

Added USD documentation highlight group tests

Simplified USD highlight groups

Moved USD `@identifier` and `@namespace` highlights into one place

Removed and simplified tests/query/highlights/usd

Simplified tests/query/highlights/usd more

Removed trailing newline

Combined USD test files

Added `set filetype=usd` to minimal_init.lua

12 files changed, 399 insertions, 0 deletions

diff --git a/README.md b/README.md
index 9938df2c4..3b9f577cc 100644
--- a/README.md
+++ b/README.md
@@ -345,6 +345,7 @@ We are looking for maintainers to add more parsers and to write query files for
 - [x] [twig](https://github.com/gbprod/tree-sitter-twig) (maintained by @gbprod)
 - [x] [typescript](https://github.com/tree-sitter/tree-sitter-typescript) (maintained by @steelsojka)
 - [x] [ungrammar](https://github.com/Philipp-M/tree-sitter-ungrammar) (maintained by @Philipp-M, @amaanq)
+- [x] [usd](https://github.com/ColinKennedy/tree-sitter-usd) (maintained by @ColinKennedy)
 - [x] [uxn tal](https://github.com/amaanq/tree-sitter-uxntal) (maintained by @amaanq)
 - [x] [v](https://github.com/vlang/vls) (maintained by @kkharji)
 - [x] [vala](https://github.com/vala-lang/tree-sitter-vala) (maintained by @Prince781)
diff --git a/lua/nvim-treesitter/parsers.lua b/lua/nvim-treesitter/parsers.lua
index c4ed3d720..8cd86213a 100644
--- a/lua/nvim-treesitter/parsers.lua
+++ b/lua/nvim-treesitter/parsers.lua
@@ -1522,6 +1522,14 @@ list.ungrammar = {
   maintainers = { "@Philipp-M", "@amaanq" },
 }
 
+list.usd = {
+  install_info = {
+    url = "https://github.com/ColinKennedy/tree-sitter-usd",
+    files = { "src/parser.c" },
+  },
+  maintainers = { "@ColinKennedy" },
+}
+
 list.uxntal = {
   install_info = {
     url = "https://github.com/amaanq/tree-sitter-uxntal",
diff --git a/queries/usd/folds.scm b/queries/usd/folds.scm
new file mode 100644
index 000000000..c4815bd07
--- /dev/null
+++ b/queries/usd/folds.scm
@@ -0,0 +1,3 @@
+[
+  (block)
+] @fold
diff --git a/queries/usd/highlights.scm b/queries/usd/highlights.scm
new file mode 100644
index 000000000..73968a647
--- /dev/null
+++ b/queries/usd/highlights.scm
@@ -0,0 +1,181 @@
+(None) @constant.builtin
+(asset_path) @text.uri
+(attribute_property) @property
+(bool) @boolean
+(comment) @comment @spell
+(custom) @function.builtin
+(float) @float
+(integer) @number
+(orderer) @function.call
+(prim_path) @string.special
+(relationship_type) @type
+(string) @string
+(uniform) @function.builtin
+(variant_set_definition) @keyword
+
+;; Prefer namespace highlighting, if any.
+;;
+;; e.g. `rel fizz` - `fizz` uses `@identifier`
+;; e.g. `rel foo:bar:fizz` - `foo` and `bar` use `@namespace` and `fizz` uses `@identifier`
+;;
+(identifier) @variable
+(namespace_identifier) @namespace
+(namespace_identifier
+  (identifier) @namespace
+)
+
+[
+  "class"
+  "def"
+  "over"
+] @keyword.function
+
+["(" ")" "[" "]" "{" "}"] @punctuation.bracket
+[":" ";" "."] @punctuation.delimiter
+
+[
+  "="
+] @operator
+
+(attribute_type) @type
+(
+ ;; Reference: https://openusd.org/release/api/sdf_page_front.html
+ (attribute_type) @type.builtin
+ (#any-of? @type.builtin
+  ;; Scalar types
+  "asset" "asset[]"
+  "bool" "bool[]"
+  "double" "double[]"
+  "float" "float[]"
+  "half" "half[]"
+  "int" "int[]"
+  "int64" "int64[]"
+  "string" "string[]"
+  "timecode" "timecode[]"
+  "token" "token[]"
+  "uchar" "uchar[]"
+  "uint" "uint[]"
+  "uint64" "uint64[]"
+
+  ;; Dimensioned Types
+  "double2" "double2[]"
+  "double3" "double3[]"
+  "double4" "double4[]"
+  "float2" "float2[]"
+  "float3" "float3[]"
+  "float4" "float4[]"
+  "half2" "half2[]"
+  "half3" "half3[]"
+  "half4" "half4[]"
+  "int2" "int2[]"
+  "int3" "int3[]"
+  "int4" "int4[]"
+  "matrix2d" "matrix2d[]"
+  "matrix3d" "matrix3d[]"
+  "matrix4d" "matrix4d[]"
+  "quatd" "quatd[]"
+  "quatf" "quatf[]"
+  "quath" "quath[]"
+
+  ;; Extra Types
+  "color3f" "color3f[]"
+  "normal3f" "normal3f[]"
+  "point3f" "point3f[]"
+  "texCoord2f" "texCoord2f[]"
+  "vector3d" "vector3d[]"
+  "vector3f" "vector3f[]"
+  "vector3h" "vector3h[]"
+
+  "dictionary"
+
+  ;; Deprecated Types
+  "EdgeIndex" "EdgeIndex[]"
+  "FaceIndex" "FaceIndex[]"
+  "Matrix4d" "Matrix4d[]"
+  "PointIndex" "PointIndex[]"
+  "PointFloat" "PointFloat[]"
+  "Transform" "Transform[]"
+  "Vec3f" "Vec3f[]"
+ )
+)
+
+(
+ (identifier) @keyword
+ (#any-of? @keyword
+
+  ;; Reference: https://openusd.org/release/api/sdf_page_front.html
+  ;; LIVRPS names
+  "inherits"
+  "payload"
+  "references"
+  "specializes"
+  "variantSets"
+  "variants"
+
+  ; assetInfo names
+  "assetInfo"
+  "identifier"
+  "name"
+  "payloadAssetDependencies"
+  "version"
+
+  ;; clips names
+  "clips"
+
+  "active"
+  "assetPaths"
+  "manifestAssetPath"
+  "primPath"
+  "templateAssetPath"
+  "templateEndTime"
+  "templateStartTime"
+  "templateStride"
+  "times"
+
+  ;; customData names
+  "customData"
+
+  "apiSchemaAutoApplyTo"
+  "apiSchemaOverridePropertyNames"
+  "className"
+  "extraPlugInfo"
+  "isUsdShadeContainer"
+  "libraryName"
+  "providesUsdShadeConnectableAPIBehavior"
+  "requiresUsdShadeEncapsulation"
+  "skipCodeGeneration"
+
+  ;; Layer metadata names
+  "colorConfiguration"
+  "colorManagementSystem"
+  "customLayerData"
+  "defaultPrim"
+  "doc"
+  "endTimeCode"
+  "framesPerSecond"
+  "owner"
+  "startTimeCode"
+  "subLayers"
+
+  ;; Prim metadata
+  "instanceable"
+ )
+)
+
+;; Common attribute metadata
+(
+ (layer_offset
+  (identifier) @keyword
+  (#any-of? @keyword
+
+   "offset"
+   "scale"
+  )
+ )
+)
+
+;; Docstrings in USD
+(metadata
+ (comment)*
+ (string) @comment.documentation
+)
diff --git a/queries/usd/indents.scm b/queries/usd/indents.scm
new file mode 100644
index 000000000..4af153034
--- /dev/null
+++ b/queries/usd/indents.scm
@@ -0,0 +1,26 @@
+[
+  (block)  ; The {}s in `def "foo" { ... Attributes / Prims here ... }`
+  (dictionary)  ; The {}s in `dictionary foo = { string "foo" = "bar" }`
+  (list)
+  (list_proxy)  ; [@foo.usda@, @bar.usda@]
+  (metadata)  ; ( anything = "goes-here" )
+  (prim_paths)  ; [</foo>, <../bar>]
+  (timeSamples)  ; The {}s in `int value.timeSamples = { 0: 1, -10: 10, ... }`
+  (tuple)
+  (variant_set_definition)  ; The {}s in `variantSet "foo" = { "vr1" { ... } "vr2" { ... } }`
+] @indent.begin
+
+(block "}" @indent.end)
+(dictionary "}" @indent.end)
+(list "]" @indent.end)
+(list_proxy "]" @indent.end)
+(metadata ")" @indent.end)
+(timeSamples "}" @indent.end)
+(tuple ")" @indent.end)
+(variant_set_definition "}" @indent.end)
+
+[
+  ")"
+  "]"
+  "}"
+] @indent.branch
diff --git a/queries/usd/locals.scm b/queries/usd/locals.scm
new file mode 100644
index 000000000..4e7e97b5f
--- /dev/null
+++ b/queries/usd/locals.scm
@@ -0,0 +1,4 @@
+[
+  (block)
+  (metadata)
+] @scope
diff --git a/scripts/minimal_init.lua b/scripts/minimal_init.lua
index e47b6701a..356745b61 100644
--- a/scripts/minimal_init.lua
+++ b/scripts/minimal_init.lua
@@ -5,6 +5,7 @@ vim.cmd [[runtime! plugin/nvim-treesitter.lua]]
 vim.cmd [[au BufRead,BufNewFile *.conf set filetype=hocon]]
 vim.cmd [[au BufRead,BufNewFile *.gleam set filetype=gleam]]
 vim.cmd [[au BufRead,BufNewFile *.ncl set filetype=nickel]]
+vim.cmd [[au BufRead,BufNewFile *.usd,*.usda set filetype=usd]]
 
 vim.o.swapfile = false
 vim.bo.swapfile = false
diff --git a/tests/indent/usd/prim.usd b/tests/indent/usd/prim.usd
new file mode 100644
index 000000000..4bfbff955
--- /dev/null
+++ b/tests/indent/usd/prim.usd
@@ -0,0 +1,6 @@
+#usda 1.0
+
+def "foo" (
+)
+{
+}
diff --git a/tests/indent/usd_spec.lua b/tests/indent/usd_spec.lua
new file mode 100644
index 000000000..c4e8198aa
--- /dev/null
+++ b/tests/indent/usd_spec.lua
@@ -0,0 +1,21 @@
+local Runner = require("tests.indent.common").Runner
+
+local run = Runner:new(it, "tests/indent/usd", {
+  tabstop = 4,
+  shiftwidth = 4,
+  softtabstop = 4,
+  expandtab = true,
+})
+
+describe("indent USD:", function()
+  describe("whole file:", function()
+    run:whole_file(".", {
+      expected_failures = {},
+    })
+  end)
+
+  describe("new line:", function()
+    run:new_line("prim.usd", { on_line = 3, text = "active = false", indent = 4 })
+    run:new_line("prim.usd", { on_line = 5, text = "custom int foo = 10", indent = 4 })
+  end)
+end)
diff --git a/tests/query/highlights/usd/prims.usda b/tests/query/highlights/usd/prims.usda
new file mode 100644
index 000000000..eeac67d74
--- /dev/null
+++ b/tests/query/highlights/usd/prims.usda
@@ -0,0 +1,118 @@
+def Xform "cube" (
+    assetInfo = {
+    # <- keyword
+        asset[] payloadAssetDependencies = [@fizz.usd@, @buzz.usd@]
+        # <- type
+        #       ^ keyword
+        #                                   ^ text.uri
+        #                                               ^ text.uri
+    }
+)
+{
+}
+
+def "root" (
+    add references = @foo.usda@</Model> (offset = 1; scale = 2.0)
+                      # <- text.uri
+                      #        ^ string.special
+                      #                  ^ keyword
+                      #                           ^ number
+                      #                            ^ punctuation.delimiter
+                      #                              ^ keyword
+                      #                                      ^ float
+)
+{
+}
+
+def "World"
+{
+    over "points" (
+        clips = {
+        # <- keyword
+            dictionary default = {
+            # <- type
+            #          ^ variable
+                double2[] times = [(101, 101), (102, 102)]
+                # <- type
+                #         ^ keyword
+                #                   ^ number
+            }
+        }
+    )
+    {
+    }
+}
+
+def Xform "torch_2" (
+    payload = @./torch.usda@
+    kind = "model"
+)
+{
+    // Pre-published light list
+    # <- comment
+    rel lightList = [ <light> ]  # inline comment
+    #                            ^ comment
+    token lightList:cacheBehavior = "consumeAndContinue"
+
+    double3 xformOp:translate = (1, 0, 0.5)
+    uniform token[] xformOpOrder = ["xformOp:translate"]
+}
+
+def "foo" (
+  "some comment"
+  # <- comment.documentation
+)
+{
+}
+
+def "foo" (
+  # inline comment
+  "actual in-description comment"
+  # <- comment.documentation
+)
+{
+}
+
+def "foo" (
+    add references = @foo.usda@
+    # <- function.call
+    append references = @foo.usda@
+    # <- function.call
+    delete references = @foo.usda@
+    # <- function.call
+    reorder references = [@foo.usda@]
+    # <- function.call
+
+    references = [@foo.usda@]  # explicit
+)
+{
+}
+
+over "Parent" (
+    prepend references = [</InternalRef>, @./ref.usda@</RefParent>]
+    # <- function.call
+    #       ^ keyword
+    #                     ^ string.special
+    #                                     ^ text.uri
+    #                                                 ^ string.special
+)
+{
+}
+
+def "foo"
+{
+    float value.timeSamples = {
+    # <- type
+    #     ^ variable
+    #           ^ property
+      -414: 14.4
+      # <- number
+      #     ^ float
+      10: 201.0,
+      # <- number
+      #   ^ float
+      10.123: 201.0123,
+      # <- float
+      #       ^ float
+    }
+}
diff --git a/tests/query/highlights/usd/properties.usda b/tests/query/highlights/usd/properties.usda
new file mode 100644
index 000000000..67df8a623
--- /dev/null
+++ b/tests/query/highlights/usd/properties.usda
@@ -0,0 +1,21 @@
+dictionary foo = {}
+# <- type
+half[] foo = [2, 1, 2]
+# <- type
+string foo = "something"
+# <- type
+timecode time = 1.0
+# <- type
+token[] purpose = ["default", "render"]
+# <- type
+
+rel material:binding:collection:Erasers = None
+# <- type
+#   ^ namespace
+#           ^ punctuation.delimiter
+#            ^ namespace
+#                   ^ punctuation.delimiter
+#                    ^ namespace
+#                              ^ punctuation.delimiter
+#                               ^ variable
+#                                         ^ constant.builtin
diff --git a/tests/query/highlights/usd/subLayers.usda b/tests/query/highlights/usd/subLayers.usda
new file mode 100644
index 000000000..b4dfa6298
--- /dev/null
+++ b/tests/query/highlights/usd/subLayers.usda
@@ -0,0 +1,9 @@
+#usda 1.0
+(
+    subLayers = [
+    # <- keyword
+        @./model_sub.usda@ (offset = 1)
+        # <- text.uri
+        #                   ^ keyword
+    ]
+)