From 5066ff2437390dc5b7709a548cf7347060f13f1a Mon Sep 17 00:00:00 2001
From: Amy Gale Ruth Bowersox <amy@erbosoft.com>
Date: Fri, 2 Aug 2024 23:55:22 -0600
Subject: [PATCH] added comment stripper preprocessor

---
 src/dragonglass/mparse.py | 53 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/src/dragonglass/mparse.py b/src/dragonglass/mparse.py
index 55e2a0d..96f0a86 100644
--- a/src/dragonglass/mparse.py
+++ b/src/dragonglass/mparse.py
@@ -28,9 +28,14 @@ GENERICIMAGE_PATTERN = r'!\[(.*?)\]\((.*?)\)'
 OBSLINK_PATTERN = r'\[\[(.*?)\]\]'
 GENERICLINK_PATTERN = r'\[(.*?)\]\((.*?)\)'
 
+# Inline footnote reference pattern.
 INLINE_FOOTNOTE_REF_PREFIX = STX + "erbosoft_fnref:"
 INLINE_FOOTNOTE_REF_PATTERN = INLINE_FOOTNOTE_REF_PREFIX + "{}" + ETX
 
+# Obsidian comment marker
+COMMENT_MARKER = '%%'
+
+
 def is_proper_url(s: str) -> bool:
     """
     Checks to see if a string is a "proper" URL.
@@ -322,6 +327,53 @@ class ObsidianInlines(Extension):
         md.inlinePatterns.register(SimpleTagInlineProcessor(r'()\=\=(.*?)\=\=', 'ins'), 'highlight', PRIO_BASE + 1)
 
 
+class ObsidianComments(Extension):
+    """An extension that removes Obsidian-style comments."""
+    class CommentStripper(Preprocessor):
+        """The actual preprocessor that removes comments."""
+        def run(self, lines: list[str]) -> list[str]:
+            """
+            Removes the comments from the array of lines.
+
+            Args:
+                lines (list[str]): The Markdown liens read in.
+
+            Returns:
+                list[str]: The Markdown lines after the comments have been removed.
+            """
+            newlines: list[str] = []
+            in_comment = False
+            defer_in_comment = False
+            for line in lines:
+                arr = line.split(COMMENT_MARKER)
+                if in_comment:
+                    arr.pop(0)
+                    in_comment = False
+                if len(arr) % 2 == 0:
+                    defer_in_comment = True
+                    if len(arr) > 0:
+                        arr.pop()
+                if not in_comment:
+                    i = len(arr) - 2
+                    while i >= 0:
+                        arr.pop(i)
+                        i -= 2
+                    newlines.append(''.join(arr))
+                    if defer_in_comment:
+                        in_comment = True
+                        defer_in_comment = False
+            return newlines
+
+    def extendMarkdown(self, md: markdown.Markdown) -> None:  # noqa: N802
+        """
+        Registers the comment remover with the Markdown parser.
+
+        Args:
+            md (markdown.Markdown): The Markdown parser to register the comment remover with.
+        """
+        md.preprocessors.register(ObsidianComments.CommentStripper(md), 'comments-multi', PRIO_BASE + 1)
+
+
 class ObsidianStyleFootnotes(FootnoteExtension):
     """
     An extension of the standard Markdown processor footnote extension to support Obsidian-style inline footnotes
@@ -452,6 +504,7 @@ def create_markdown_parser(context: Context) -> markdown.Markdown:
         markdown.Markdown: The new Markdown parser.
     """
     return markdown.Markdown(extensions=[MetaStripper(),
+                                         ObsidianComments(),
                                          ObsidianStyleFootnotes(SUPERSCRIPT_TEXT='[{}]', SEPARATOR='-'),
                                          ObsidianImages(context),
                                          ObsidianLinks(context),