refactor: extract renderer classes to separate files

Split the renderer module into focused single-responsibility files
for better maintainability and clearer code organization.

Changes:
- Extract `MDRender` class to `renderer/md_render.py`
- Extract `RenderNode` class to `renderer/render_node.py`
- Extract `render_with_features()` to `renderer/dispatch.py`
- Simplify `renderer/__init__.py` to re-export public API

Author: drmingdrmer

md2zhihu/__init__.py

@@ -24,8 +24,8 @@
 from .parser import FrontMatter
 from .parser import ParserConfig
 from .parser import load_external_refs
-from .renderer import MDRender
 from .renderer import RenderNode
+from .renderer.md_render import MDRender
 from .utils import add_paragraph_end
 from .utils import asset_fn
 from .utils import escape

md2zhihu/renderer/__init__.py

@@ -1,244 +1,4 @@
 """Renderer classes for md2zhihu"""
 
-import pprint
-from typing import List
-from typing import Optional
-
-from ..utils import add_paragraph_end
-from ..utils import indent
-from ..utils import msg
-from ..utils import strip_paragraph_end
-
-
-class MDRender(object):
-    # platform specific renderer
-
-    def __init__(self, conf, features: dict):
-        self.conf = conf
-        self.features = features
-
-    def render_node(self, rnode):
-        """
-        Render a AST node into lines of text
-
-        Args:
-            rnode is a RenderNode instance
-        """
-
-        n = rnode.node
-        typ = n["type"]
-
-        #  customized renderers:
-
-        lines = render_with_features(self, rnode, self.features)
-        if lines is not None:
-            return lines
-        else:
-            # can not render, continue with default handler
-            pass
-
-        # default renderers:
-
-        if typ == "thematic_break":
-            return ["---", ""]
-
-        if typ == "paragraph":
-            lines = self.render(rnode)
-            return "".join(lines).split("\n") + [""]
-
-        if typ == "text":
-            return [n["text"]]
-
-        if typ == "strong":
-            lines = self.render(rnode)
-            lines[0] = "**" + lines[0]
-            lines[-1] = lines[-1] + "**"
-            return lines
-
-        if typ == "math_block":
-            return ["$$", n["text"], "$$"]
-
-        if typ == "math_inline":
-            return ["$$ " + n["text"].strip() + " $$"]
-
-        if typ == "table":
-            return self.render(rnode) + [""]
-
-        if typ == "table_head":
-            alignmap = {
-                "left": ":--",
-                "right": "--:",
-                "center": ":-:",
-                None: "---",
-            }
-            lines = self.render(rnode)
-            aligns = [alignmap[x["align"]] for x in n["children"]]
-            aligns = "| " + " | ".join(aligns) + " |"
-            return ["| " + " | ".join(lines) + " |", aligns]
-
-        if typ == "table_cell":
-            lines = self.render(rnode)
-            return ["".join(lines)]
-
-        if typ == "table_body":
-            return self.render(rnode)
-
-        if typ == "table_row":
-            lines = self.render(rnode)
-            return ["| " + " | ".join(lines) + " |"]
-
-        if typ == "block_code":
-            # remove the last \n
-            return ["```" + (n["info"] or "")] + n["text"][:-1].split("\n") + ["```", ""]
-
-        if typ == "codespan":
-            return [("`" + n["text"] + "`")]
-
-        if typ == "image":
-            if n["title"] is None:
-                return ["![{alt}]({src})".format(**n)]
-            else:
-                return ["![{alt}]({src} {title})".format(**n)]
-
-        if typ == "list":
-            lines = self.render(rnode)
-            return add_paragraph_end(lines)
-
-        if typ == "list_item":
-            lines = self.render(rnode)
-
-            # parent is a `list` node
-            parent = rnode.parent
-            assert parent.node["type"] == "list"
-
-            head = "-   "
-            if parent.node["ordered"]:
-                head = "1.  "
-
-            lines[0] = head + lines[0]
-            lines = lines[0:1] + [indent(x) for x in lines[1:]]
-            return lines
-
-        if typ == "block_text":
-            lines = self.render(rnode)
-            return "".join(lines).split("\n")
-
-        if typ == "block_quote":
-            lines = self.render(rnode)
-            lines = strip_paragraph_end(lines)
-            lines = ["> " + x for x in lines]
-            return lines + [""]
-
-        if typ == "newline":
-            return [""]
-
-        if typ == "block_html":
-            return add_paragraph_end([n["text"]])
-
-        if typ == "link":
-            #  TODO title
-            lines = self.render(rnode)
-            lines[0] = "[" + lines[0]
-            lines[-1] = lines[-1] + "](" + n["link"] + ")"
-
-            return lines
-
-        if typ == "heading":
-            lines = self.render(rnode)
-            lines[0] = "#" * n["level"] + " " + lines[0]
-            return lines + [""]
-
-        if typ == "strikethrough":
-            lines = self.render(rnode)
-            lines[0] = "~~" + lines[0]
-            lines[-1] = lines[-1] + "~~"
-            return lines
-
-        if typ == "emphasis":
-            lines = self.render(rnode)
-            lines[0] = "*" + lines[0]
-            lines[-1] = lines[-1] + "*"
-            return lines
-
-        if typ == "inline_html":
-            return [n["text"]]
-
-        if typ == "linebreak":
-            return ["  \n"]
-
-        print(typ, n.keys())
-        pprint.pprint(n)
-        return ["***:" + typ]
-
-    def render(self, rnode) -> List[str]:
-        rst = []
-        for n in rnode.node["children"]:
-            child = rnode.new_child(n)
-            lines = self.render_node(child)
-            rst.extend(lines)
-
-        return rst
-
-    def msg(self, *args):
-        msg(*args)
-
-
-class RenderNode(object):
-    """
-    RenderNode is a container of current ast-node and parent
-    """
-
-    def __init__(self, n, parent=None):
-        """
-        :param n: ast node: a normal dictionary such as {'type': 'text' ... }
-        :param parent: parent RenderNode
-        """
-        self.node = n
-
-        self.level = 0
-
-        # parent RenderNode
-        self.parent = parent
-
-    def new_child(self, n):
-        c = RenderNode(n, parent=self)
-        c.level = self.level + 1
-        return c
-
-    def to_str(self):
-        t = "{}".format(self.node.get("type"))
-        if self.parent is None:
-            return t
-
-        return self.parent.to_str() + " -> " + t
-
-
-#  features: {typ:action(), typ2:{subtyp:action()}}
-def render_with_features(mdrender, rnode: RenderNode, features=None) -> Optional[List[str]]:
-    if features is None:
-        features = {}
-
-    n = rnode.node
-
-    node_type = n["type"]
-
-    if node_type not in features:
-        if "*" in features:
-            return features["*"](mdrender, rnode)
-        else:
-            return None
-
-    type_handler = features[node_type]
-    if callable(type_handler):
-        return type_handler(mdrender, rnode)
-
-    #  subtype is info, the type after "```"
-    lang = n["info"] or ""
-
-    if lang in type_handler:
-        return type_handler[lang](mdrender, rnode)
-
-    if "*" in type_handler:
-        return type_handler["*"](mdrender, rnode)
-
-    return None
+from .md_render import MDRender
+from .render_node import RenderNode

md2zhihu/renderer/dispatch.py

@@ -0,0 +1,35 @@
+from typing import List
+from typing import Optional
+
+from .render_node import RenderNode
+
+
+#  features: {typ:action(), typ2:{subtyp:action()}}
+def render_with_features(mdrender, rnode: RenderNode, features=None) -> Optional[List[str]]:
+    if features is None:
+        features = {}
+
+    n = rnode.node
+
+    node_type = n["type"]
+
+    if node_type not in features:
+        if "*" in features:
+            return features["*"](mdrender, rnode)
+        else:
+            return None
+
+    type_handler = features[node_type]
+    if callable(type_handler):
+        return type_handler(mdrender, rnode)
+
+    #  subtype is info, the type after "```"
+    lang = n["info"] or ""
+
+    if lang in type_handler:
+        return type_handler[lang](mdrender, rnode)
+
+    if "*" in type_handler:
+        return type_handler["*"](mdrender, rnode)
+
+    return None