diff --git a/grammar.js b/grammar.js
index 896042f..e8cb50b 100644
--- a/grammar.js
+++ b/grammar.js
@@ -69,6 +69,7 @@ module.exports = grammar({
     [$.class_list],
     [$.attr_value_list],
     [$._text_block_attrs],
+    [$._identifier],
   ],
 
   rules: {
@@ -93,12 +94,24 @@ module.exports = grammar({
 
     connection: ($) =>
       seq(
-        $._connection_path,
-        repeat1(seq($.arrow, $._connection_path)),
+        choice(
+          $._full_connection_path,
+          alias($._referencing_full_connection_path, $.referencing)
+        ),
         optional(seq($._colon, optional($.label))),
         optional(seq(alias($._connection_block, $.block)))
       ),
 
+    _referencing_full_connection_path: ($) =>
+      seq("(", $._full_connection_path, $._referencing_end, optional($.index)),
+
+    _referencing_end: ($) => token(prec(PREC.IDENTIFIER + 1, ")")),
+
+    index: ($) => seq("[", $.integer, "]"),
+
+    _full_connection_path: ($) =>
+      seq($._connection_path, repeat1(seq($.arrow, $._connection_path))),
+
     _connection_path: ($) =>
       seq(
         repeat(
@@ -201,11 +214,17 @@ module.exports = grammar({
         repeat(
           choice(
             $.escape_sequence,
-            token(prec(PREC.IDENTIFIER, /[\w\d'"$(),]+/)),
-            token(prec(PREC.IDENTIFIER, /( +|-)[\w\d'"$()]+/))
+            token(prec(PREC.IDENTIFIER, /[\w\d'"$(,]+/)),
+            token(prec(PREC.IDENTIFIER, /( +|-)[\w\d'"$(]+/)),
+            token(prec(PREC.IDENTIFIER, ")"))
+          )
+        ),
+        optional(
+          choice(
+            token(prec(PREC.IDENTIFIER, /[\w\d'"$(]+/)),
+            token(prec(PREC.IDENTIFIER + 1, ")"))
           )
         ),
-        optional(token(prec(PREC.IDENTIFIER, /[\w\d'"$()]+/))),
         optional($._dash)
       ),
 
diff --git a/src/grammar.json b/src/grammar.json
index 90a9fb0..e6a0560 100644
--- a/src/grammar.json
+++ b/src/grammar.json
@@ -69,24 +69,22 @@
       "type": "SEQ",
       "members": [
         {
-          "type": "SYMBOL",
-          "name": "_connection_path"
-        },
-        {
-          "type": "REPEAT1",
-          "content": {
-            "type": "SEQ",
-            "members": [
-              {
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "SYMBOL",
+              "name": "_full_connection_path"
+            },
+            {
+              "type": "ALIAS",
+              "content": {
                 "type": "SYMBOL",
-                "name": "arrow"
+                "name": "_referencing_full_connection_path"
               },
-              {
-                "type": "SYMBOL",
-                "name": "_connection_path"
-              }
-            ]
-          }
+              "named": true,
+              "value": "referencing"
+            }
+          ]
         },
         {
           "type": "CHOICE",
@@ -141,6 +139,88 @@
         }
       ]
     },
+    "_referencing_full_connection_path": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "("
+        },
+        {
+          "type": "SYMBOL",
+          "name": "_full_connection_path"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "_referencing_end"
+        },
+        {
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "SYMBOL",
+              "name": "index"
+            },
+            {
+              "type": "BLANK"
+            }
+          ]
+        }
+      ]
+    },
+    "_referencing_end": {
+      "type": "TOKEN",
+      "content": {
+        "type": "PREC",
+        "value": 1,
+        "content": {
+          "type": "STRING",
+          "value": ")"
+        }
+      }
+    },
+    "index": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "["
+        },
+        {
+          "type": "SYMBOL",
+          "name": "integer"
+        },
+        {
+          "type": "STRING",
+          "value": "]"
+        }
+      ]
+    },
+    "_full_connection_path": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "SYMBOL",
+          "name": "_connection_path"
+        },
+        {
+          "type": "REPEAT1",
+          "content": {
+            "type": "SEQ",
+            "members": [
+              {
+                "type": "SYMBOL",
+                "name": "arrow"
+              },
+              {
+                "type": "SYMBOL",
+                "name": "_connection_path"
+              }
+            ]
+          }
+        }
+      ]
+    },
     "_connection_path": {
       "type": "SEQ",
       "members": [
@@ -893,7 +973,7 @@
                   "value": 0,
                   "content": {
                     "type": "PATTERN",
-                    "value": "[\\w\\d'\"$(),]+"
+                    "value": "[\\w\\d'\"$(,]+"
                   }
                 }
               },
@@ -904,7 +984,18 @@
                   "value": 0,
                   "content": {
                     "type": "PATTERN",
-                    "value": "( +|-)[\\w\\d'\"$()]+"
+                    "value": "( +|-)[\\w\\d'\"$(]+"
+                  }
+                }
+              },
+              {
+                "type": "TOKEN",
+                "content": {
+                  "type": "PREC",
+                  "value": 0,
+                  "content": {
+                    "type": "STRING",
+                    "value": ")"
                   }
                 }
               }
@@ -915,15 +1006,31 @@
           "type": "CHOICE",
           "members": [
             {
-              "type": "TOKEN",
-              "content": {
-                "type": "PREC",
-                "value": 0,
-                "content": {
-                  "type": "PATTERN",
-                  "value": "[\\w\\d'\"$()]+"
+              "type": "CHOICE",
+              "members": [
+                {
+                  "type": "TOKEN",
+                  "content": {
+                    "type": "PREC",
+                    "value": 0,
+                    "content": {
+                      "type": "PATTERN",
+                      "value": "[\\w\\d'\"$(]+"
+                    }
+                  }
+                },
+                {
+                  "type": "TOKEN",
+                  "content": {
+                    "type": "PREC",
+                    "value": 1,
+                    "content": {
+                      "type": "STRING",
+                      "value": ")"
+                    }
+                  }
                 }
-              }
+              ]
             },
             {
               "type": "BLANK"
@@ -2287,6 +2394,9 @@
     ],
     [
       "_text_block_attrs"
+    ],
+    [
+      "_identifier"
     ]
   ],
   "precedences": [],
diff --git a/src/node-types.json b/src/node-types.json
index 307e03b..5193755 100644
--- a/src/node-types.json
+++ b/src/node-types.json
@@ -261,7 +261,7 @@
     "fields": {},
     "children": {
       "multiple": true,
-      "required": true,
+      "required": false,
       "types": [
         {
           "type": "arrow",
@@ -283,6 +283,10 @@
           "type": "label",
           "named": true
         },
+        {
+          "type": "referencing",
+          "named": true
+        },
         {
           "type": "shape_key",
           "named": true
@@ -348,6 +352,21 @@
       ]
     }
   },
+  {
+    "type": "index",
+    "named": true,
+    "fields": {},
+    "children": {
+      "multiple": false,
+      "required": true,
+      "types": [
+        {
+          "type": "integer",
+          "named": true
+        }
+      ]
+    }
+  },
   {
     "type": "label",
     "named": true,
@@ -367,6 +386,37 @@
       ]
     }
   },
+  {
+    "type": "referencing",
+    "named": true,
+    "fields": {},
+    "children": {
+      "multiple": true,
+      "required": false,
+      "types": [
+        {
+          "type": "arrow",
+          "named": true
+        },
+        {
+          "type": "container_key",
+          "named": true
+        },
+        {
+          "type": "dot",
+          "named": true
+        },
+        {
+          "type": "index",
+          "named": true
+        },
+        {
+          "type": "shape_key",
+          "named": true
+        }
+      ]
+    }
+  },
   {
     "type": "reserved",
     "named": true,
@@ -511,6 +561,14 @@
     "type": "'",
     "named": false
   },
+  {
+    "type": "(",
+    "named": false
+  },
+  {
+    "type": ")",
+    "named": false
+  },
   {
     "type": "3d",
     "named": false
diff --git a/src/parser.c b/src/parser.c
index be0e836..497b52a 100644
Binary files a/src/parser.c and b/src/parser.c differ
diff --git a/test/corpus/connection.txt b/test/corpus/connection.txt
index 205c0c0..4c68529 100644
--- a/test/corpus/connection.txt
+++ b/test/corpus/connection.txt
@@ -248,7 +248,7 @@ Connection with espaced key fragments
 
 
 ================================================================================
-Connection with espaced key fragments
+Diclare a connection with espaced key fragments
 ================================================================================
 \#hello\[\] -- \[world\]
 
@@ -268,3 +268,111 @@ Connection with espaced key fragments
     )
   )
 )
+
+================================================================================
+Declare a referencing connection 
+================================================================================
+(x() -> y())
+(x() -> y())[0]
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (connection
+    (referencing
+      (shape_key)
+      (arrow)
+      (shape_key)
+    )
+  )
+  (connection
+    (referencing
+      (shape_key)
+      (arrow)
+      (shape_key)
+      (index (integer))
+    )
+  )
+)
+
+================================================================================
+Declare a referencing connection with label
+================================================================================
+(x -> y): label
+(x -> y)[0]: label
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (connection
+    (referencing
+      (shape_key)
+      (arrow)
+      (shape_key)
+    )
+    (label)
+  )
+  (connection
+    (referencing
+      (shape_key)
+      (arrow)
+      (shape_key)
+      (index (integer))
+    )
+    (label)
+  )
+)
+
+================================================================================
+Declare a referencing connection with block
+================================================================================
+(x() -> y()): {
+  style.stroke: \#ff0000
+}
+(x -> y)[0]: {
+  style.stroke: \#ff0000
+}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (connection
+    (referencing
+      (shape_key)
+      (arrow)
+      (shape_key)
+    )
+    (block
+      (attribute
+        (keyword_style)
+        (dot)
+        (attribute
+          (attr_key)
+          (attr_value
+            (escape_sequence)
+          )
+        )
+      )
+    )
+  )
+  (connection
+    (referencing
+      (shape_key)
+      (arrow)
+      (shape_key)
+      (index (integer))
+    )
+    (block
+      (attribute
+        (keyword_style)
+        (dot)
+        (attribute
+          (attr_key)
+          (attr_value
+            (escape_sequence)
+          )
+        )
+      )
+    )
+  )
+)
diff --git a/tree-sitter-d2.wasm b/tree-sitter-d2.wasm
index bb6e05b..3efa1ad 100755
Binary files a/tree-sitter-d2.wasm and b/tree-sitter-d2.wasm differ