grammar: add support of underscore keyword...

...to ref the parent container

Closes #5

examples/chess.d2

@@ -1,12 +1,7 @@
 # Actors
 hans: Hans Niemann
 
-defendants: |md
-  # Defendants
-
-  hello world
-| {
-  shape: text
+defendants: {
   mc: Magnus Carlsen
   playmagnus: Play Magnus Group
   chesscom: Chess.com

flake.lock

@@ -32,16 +32,16 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1686737040,
-        "narHash": "sha256-R+JicNaI9mcxodtHkci894txjt4IMsfOnlAarA/r0xQ=",
+        "lastModified": 1686736559,
+        "narHash": "sha256-YyUSVoOKIDAscTx7IZhF9x3qgZ9dPNF19fKk+4c5irc=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "6d1d80a232a355a65dc4d3bfea1f108e8dac1340",
+        "rev": "ddf4688dc7aeb14e8a3c549cb6aa6337f187a884",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
+        "ref": "nixos-23.05",
         "repo": "nixpkgs",
         "type": "github"
       }

flake.nix

@@ -1,6 +1,6 @@
 {
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05";
     flake-utils.url = "github:numtide/flake-utils";
     tools.url = "git+https://git.pleshevski.ru/mynix/tools";
   };

grammar.js

@@ -188,7 +188,7 @@ module.exports = grammar({
         )
       ),
 
-    shape_key: ($) => choice($.string, $._identifier),
+    shape_key: ($) => choice($.keyword_underscore, $.string, $._identifier),
 
     _identifier: ($) =>
       seq(
@@ -348,6 +348,7 @@ module.exports = grammar({
     _connection_arrowhead_attr_key: ($) =>
       choice("source-arrowhead", "target-arrowhead"),
 
+    keyword_underscore: (_) => "_",
     keyword_classes: (_) => "classes",
     keyword_class: (_) => "class",
     keyword_style: (_) => "style",

queries/highlights.scm

@@ -4,12 +4,15 @@
 (shape_key) @variable
 (attr_key) @property
 (reserved) @error
+(class_name) @constant
+
 [
   (keyword_style)
   (keyword_classes)
   (keyword_class)
 ] @keyword
-(class_name) @constant
+
+(keyword_underscore) @keyword.return
 
 ; Literals
 ;-------------------------------------------------------------------------------
@@ -27,9 +30,11 @@
 ; Comments
 ;-------------------------------------------------------------------------------
 
-(language) @comment
-(line_comment) @comment.line
-(block_comment) @comment.block
+[
+  (language)
+  (line_comment)
+  (block_comment)
+] @comment
 
 ; Punctiation
 ;-------------------------------------------------------------------------------

src/grammar.json

@@ -853,6 +853,10 @@
     "shape_key": {
       "type": "CHOICE",
       "members": [
+        {
+          "type": "SYMBOL",
+          "name": "keyword_underscore"
+        },
         {
           "type": "SYMBOL",
           "name": "string"
@@ -1818,6 +1822,10 @@
         }
       ]
     },
+    "keyword_underscore": {
+      "type": "STRING",
+      "value": "_"
+    },
     "keyword_classes": {
       "type": "STRING",
       "value": "classes"

src/node-types.json

@@ -186,6 +186,10 @@
           "type": "escape_sequence",
           "named": true
         },
+        {
+          "type": "keyword_underscore",
+          "named": true
+        },
         {
           "type": "string",
           "named": true
@@ -314,6 +318,10 @@
           "type": "escape_sequence",
           "named": true
         },
+        {
+          "type": "keyword_underscore",
+          "named": true
+        },
         {
           "type": "string",
           "named": true
@@ -392,6 +400,10 @@
           "type": "escape_sequence",
           "named": true
         },
+        {
+          "type": "keyword_underscore",
+          "named": true
+        },
         {
           "type": "string",
           "named": true
@@ -612,6 +624,10 @@
     "type": "keyword_style",
     "named": true
   },
+  {
+    "type": "keyword_underscore",
+    "named": true
+  },
   {
     "type": "label",
     "named": false

test/corpus/container.txt

@@ -267,3 +267,25 @@ primty: Primitive types {
     )
   )
 )
+
+================================================================================
+Declare a container with a references to the parent container
+================================================================================
+container: {
+  _.foo: baz
+}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (container
+    (container_key)
+    (block
+      (container
+        (container_key (keyword_underscore))
+        (dot)
+        (shape (shape_key) (label))
+      )
+    )
+  )
+)

test/corpus/shape.txt

@@ -278,3 +278,13 @@ bar
   (block_comment)
   (shape (shape_key))
 )
+
+================================================================================
+Declare a shape with a parent container reference
+================================================================================
+_
+--------------------------------------------------------------------------------
+
+(source_file
+  (shape (shape_key (keyword_underscore)))
+)

test/highlight/shape.d2

@@ -33,6 +33,12 @@ foo: Foo Bar {
   bar.baz
   # <- string.special
   #   ^ variable
+
+  _.foo.style.fill: "#8800aa"
+  # <- keyword.return
+  # ^ variable
+  #     ^ keyword
+  #           ^ property
 }
 # <- punctuation.bracket