👌 IMPROVE: Add RendererProtocol typing

markdown_it/main.py

@@ -18,7 +18,7 @@
 from .parser_block import ParserBlock  # noqa F401
 from .parser_inline import ParserInline  # noqa F401
 from .rules_core.state_core import StateCore
-from .renderer import RendererHTML
+from .renderer import RendererHTML, RendererProtocol
 from .utils import AttrDict
 
 try:
@@ -42,7 +42,7 @@ def __init__(
         config: Union[str, Mapping] = "commonmark",
         options_update: Optional[Mapping] = None,
         *,
-        renderer_cls=RendererHTML,
+        renderer_cls: Callable[["MarkdownIt"], RendererProtocol] = RendererHTML,
     ):
         """Main parser class
 

markdown_it/renderer.py

@@ -6,13 +6,35 @@ class Renderer
 rules if you create plugin and adds new token types.
 """
 import inspect
-from typing import Optional, Sequence
+import sys
+from typing import (
+    Any,
+    ClassVar,
+    Mapping,
+    MutableMapping,
+    Optional,
+    Sequence,
+)
 
 from .common.utils import unescapeAll, escapeHtml
 from .token import Token
 
+if sys.version_info < (3, 8):
+    from typing_extensions import Protocol
+else:
+    from typing import Protocol
 
-class RendererHTML:
+
+class RendererProtocol(Protocol):
+    __output__: ClassVar[str]
+
+    def render(
+        self, tokens: Sequence[Token], options: Mapping[str, Any], env: MutableMapping
+    ) -> str:
+        ...
+
+
+class RendererHTML(RendererProtocol):
     """Contains render rules for tokens. Can be updated and extended.
 
     Example:

setup.py

@@ -40,7 +40,11 @@ def get_version():
     ],
     keywords="markdown lexer parser development",
     python_requires="~=3.6",
-    install_requires=["attrs>=19,<21", "mdit-py-plugins~=0.2.6"],
+    install_requires=[
+        "attrs>=19,<21",
+        "mdit-py-plugins~=0.2.6",
+        "typing_extensions>=3.7.4; python_version<'3.8'",
+    ],
     extras_require={
         "code_style": ["pre-commit==2.6"],
         "testing": [