Support wildcard nodes _ (#15)

Ref: - nvim-treesitter/nvim-treesitter#1405 (comment) - tree-sitter/tree-sitter#1253
tree-sitter-grammars · Jul 13, 2021 · 9a2ccff · 9a2ccff
1 parent bc753fa
commit 9a2ccff
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Showing 5 changed files with 3,125 additions and 2,262 deletions.
diff --git a/corpus/statements.txt b/corpus/statements.txt
@@ -24,8 +24,10 @@ Anonymous nodes
 (program
   (named_node
     name: (identifier))
-  (anonymous_node)
-  (anonymous_node))
+  (anonymous_node
+    name: (identifier))
+  (anonymous_node
+    name: (identifier)))
 
 ================================================================================
 Anonymous nodes (series)
@@ -37,8 +39,51 @@ Anonymous nodes (series)
 
 (program
   (grouping
-    (anonymous_node)
-    (anonymous_node)))
+    (anonymous_node
+      name: (identifier))
+    (anonymous_node
+      name: (identifier))))
+
+================================================================================
+Wildcard nodes
+================================================================================
+
+_ @wildcard
+
+(_) @wildcard
+
+(node _ @wildcard)
+
+(program
+  name: (_))
+
+(program
+  name: _)
+
+--------------------------------------------------------------------------------
+
+(program
+  (anonymous_node
+    (capture
+      (identifier)))
+  (named_node
+    (capture
+      (identifier)))
+  (named_node
+    (identifier)
+    (anonymous_node
+      (capture
+        (identifier))))
+  (named_node
+    (identifier)
+    (field_definition
+      (identifier)
+      (named_node)))
+  (named_node
+    (identifier)
+    (field_definition
+      (identifier)
+      (anonymous_node))))
 
 ================================================================================
 Field names
@@ -127,7 +172,8 @@ Groups
     (list
       (named_node
         name: (identifier))
-      (anonymous_node))))
+      (anonymous_node
+        name: (identifier)))))
 
 ================================================================================
 Captures
@@ -173,26 +219,26 @@ Lists
 
 (program
   (list
-    (anonymous_node)
-    (anonymous_node)
-    (anonymous_node)
+    (anonymous_node
+      name: (identifier))
+    (anonymous_node
+      name: (identifier))
+    (anonymous_node
+      name: (identifier))
     (capture
       name: (identifier)))
   (named_node
     name: (identifier)
     (list
       (field_definition
         name: (identifier)
-        (named_node
-          name: (identifier)))
+        (named_node))
       (field_definition
         name: (identifier)
-        (named_node
-          name: (identifier)))
+        (named_node))
       (field_definition
         name: (identifier)
         (named_node
-          name: (identifier)
           quantifier: (quantifier)))
       (capture
         name: (identifier)))
@@ -280,18 +326,23 @@ Immediate Child Operator
   (grouping
     (named_node
       name: (identifier))
-    (anonymous_node)
+    (anonymous_node
+      name: (identifier))
     (named_node
       name: (identifier)))
   (grouping
-    (anonymous_node)
-    (anonymous_node))
+    (anonymous_node
+      name: (identifier))
+    (anonymous_node
+      name: (identifier)))
   (grouping
     (named_node
       name: (identifier))
-    (anonymous_node))
+    (anonymous_node
+      name: (identifier)))
   (grouping
-    (anonymous_node)
+    (anonymous_node
+      name: (identifier))
     (named_node
       name: (identifier)))
   (grouping
@@ -300,7 +351,8 @@ Immediate Child Operator
     (list
       (named_node
         name: (identifier))
-      (anonymous_node))
+      (anonymous_node
+        name: (identifier)))
     (named_node
       name: (identifier)))
   (grouping
@@ -309,7 +361,8 @@ Immediate Child Operator
     (list
       (named_node
         name: (identifier))
-      (anonymous_node))
+      (anonymous_node
+        name: (identifier)))
     (named_node
       name: (identifier)))
   (grouping
@@ -318,7 +371,8 @@ Immediate Child Operator
     (list
       (named_node
         name: (identifier))
-      (anonymous_node))
+      (anonymous_node
+        name: (identifier)))
     (named_node
       name: (identifier)))
   (grouping
@@ -327,7 +381,8 @@ Immediate Child Operator
     (list
       (named_node
         name: (identifier))
-      (anonymous_node))
+      (anonymous_node
+        name: (identifier)))
     (list
       (named_node
         name: (identifier))))
@@ -337,7 +392,8 @@ Immediate Child Operator
     (list
       (named_node
         name: (identifier))
-      (anonymous_node))
+      (anonymous_node
+        name: (identifier)))
     (list
       (named_node
         name: (identifier))))
@@ -355,40 +411,48 @@ Immediate Child Operator
       name: (identifier)))
   (named_node
     name: (identifier)
-    (anonymous_node))
+    (anonymous_node
+      name: (identifier)))
   (named_node
     name: (identifier)
-    (anonymous_node))
+    (anonymous_node
+      name: (identifier)))
   (named_node
     name: (identifier)
-    (anonymous_node)
-    (anonymous_node))
+    (anonymous_node
+      name: (identifier))
+    (anonymous_node
+      name: (identifier)))
   (named_node
     name: (identifier)
     (named_node
       name: (identifier))
-    (anonymous_node)
+    (anonymous_node
+      name: (identifier))
     (named_node
       name: (identifier)))
   (named_node
     name: (identifier)
     (named_node
       name: (identifier))
-    (anonymous_node)
+    (anonymous_node
+      name: (identifier))
     (named_node
       name: (identifier)))
   (named_node
     name: (identifier)
     (named_node
       name: (identifier))
-    (anonymous_node)
+    (anonymous_node
+      name: (identifier))
     (named_node
       name: (identifier)))
   (named_node
     name: (identifier)
     (named_node
       name: (identifier))
-    (anonymous_node)
+    (anonymous_node
+      name: (identifier))
     (named_node
       name: (identifier)))
   (named_node

diff --git a/grammar.js b/grammar.js
@@ -4,6 +4,8 @@ const PREC = {
   // Prefer a string over a comment
   COMMENT: 1,
   STRING: 2,
+
+  WILDCARD_NODE: 1,
 };
 
 module.exports = grammar({
@@ -62,9 +64,10 @@ module.exports = grammar({
     quantifier: $ => choice("*", "+", "?"),
 
     identifier: $ => /[a-zA-Z0-9.\-_\$#]+/,
+    _node_identifier: $ => choice($.identifier, prec(PREC.WILDCARD_NODE, "_")),
     capture: $ => seq("@", field("name", $.identifier)),
     string: $ => $._string,
-    parameters: $ => repeat1(choice($.capture, $.string, $.identifier)),
+    parameters: $ => repeat1(choice($.capture, $.string, $._node_identifier)),
     comment: $ => token(prec(PREC.COMMENT, seq(";", /.*/))),
     list: $ => seq("[", repeat(choice($._definition, $.field_definition)), "]", quantifier($), captures($)),
 
@@ -76,11 +79,15 @@ module.exports = grammar({
       captures($),
     ),
 
-    anonymous_node: $ => seq($._string, quantifier($), captures($)),
+    anonymous_node: $ => seq(
+      field("name", choice(alias($._string, $.identifier), "_")),
+      quantifier($),
+      captures($),
+    ),
 
     named_node: $ => seq(
       "(",
-      field("name", $.identifier),
+      field("name", $._node_identifier),
       optional(
         seq(
           optional("."),

diff --git a/src/grammar.json b/src/grammar.json
@@ -204,6 +204,23 @@
       "type": "PATTERN",
       "value": "[a-zA-Z0-9.\\-_\\$#]+"
     },
+    "_node_identifier": {
+      "type": "CHOICE",
+      "members": [
+        {
+          "type": "SYMBOL",
+          "name": "identifier"
+        },
+        {
+          "type": "PREC",
+          "value": 1,
+          "content": {
+            "type": "STRING",
+            "value": "_"
+          }
+        }
+      ]
+    },
     "capture": {
       "type": "SEQ",
       "members": [
@@ -240,7 +257,7 @@
           },
           {
             "type": "SYMBOL",
-            "name": "identifier"
+            "name": "_node_identifier"
           }
         ]
       }
@@ -380,8 +397,26 @@
       "type": "SEQ",
       "members": [
         {
-          "type": "SYMBOL",
-          "name": "_string"
+          "type": "FIELD",
+          "name": "name",
+          "content": {
+            "type": "CHOICE",
+            "members": [
+              {
+                "type": "ALIAS",
+                "content": {
+                  "type": "SYMBOL",
+                  "name": "_string"
+                },
+                "named": true,
+                "value": "identifier"
+              },
+              {
+                "type": "STRING",
+                "value": "_"
+              }
+            ]
+          }
         },
         {
           "type": "CHOICE",
@@ -428,7 +463,7 @@
           "name": "name",
           "content": {
             "type": "SYMBOL",
-            "name": "identifier"
+            "name": "_node_identifier"
           }
         },
         {