refactor: avoid parsing document twice for figure numbers

renderer/referenced_token.py

@@ -3,15 +3,16 @@ from mistletoe.block_token import BlockToken
 
 
 class ReferencedToken(BlockToken):
-    line_number: int = -1
-    marker: str = None
-    label: str = None
-
     def __init__(self, marker: str):
-        self.marker = marker
-
-        if marker not in mistletoe.token._root_node.references:
-            self.label = len(mistletoe.token._root_node.references) + 1
-            mistletoe.token._root_node.references[marker] = self.label
+        if marker != "":
+            self.marker = marker
+            references = mistletoe.token._root_node.references
+            if marker not in references:
+                label = str(len(references) + 1)
+                references[marker] = label
+            else:
+                label = references[marker]
+            self.label = label
         else:
-            self.label = mistletoe._root_node.references[marker]
+            self.marker = None
+            self.label = None