Rewrite emphasis handling

docs/changelog.md

@@ -20,6 +20,7 @@ See the [Contributing Guide](contributing.md) for details.
   performance for repeated inline patterns (#1619).
 * Officially support Python 3.15 and drop support for Python 3.10
 * Walk backtick runs in `BacktickInlineProcessor` without a regex (#1620).
+* Complete rework of emphasis handling to imporove nested emphasis handling better (#1632).
 
 ### Fixed
 

docs/extensions/api.md

@@ -349,7 +349,7 @@ Here are some convenience functions and other examples:
 
 | Class                                                                                | Kind      | Description                                                   |
 | -------------------------------------------------------------------------------------|-----------|---------------------------------------------------------------|
-| [`AsteriskProcessor`][markdown.inlinepatterns.AsteriskProcessor]                     | built-in  | Emphasis processor for handling strong and em matches inside asterisks |
+| [`DelimiterProcessor`][markdown.inlinepatterns.DelimiterProcessor]                    | built-in  | Emphasis processor for handling strong and em matches        |
 | [`WikiLinksInlineProcessor`][markdown.extensions.wikilinks.WikiLinksInlineProcessor] | extension | Link `[[article names]]` to wiki given in metadata            |
 | [`FootnoteInlineProcessor`][markdown.extensions.footnotes.FootnoteInlineProcessor]   | extension | Replaces footnote in text with link to footnote div at bottom |
 

markdown/core.py

@@ -20,6 +20,7 @@
 from __future__ import annotations
 
 import codecs
+import time
 import sys
 import logging
 import importlib
@@ -106,6 +107,7 @@ def __init__(self, **kwargs):
 
         """
 
+        self.last_run: float = 0.0
         self.tab_length: int = kwargs.get('tab_length', 4)
 
         self.ESCAPED_CHARS: list[str] = [
@@ -267,6 +269,7 @@ def reset(self) -> Markdown:
         Called once upon creation of a class instance. Should be called manually between calls
         to [`Markdown.convert`][markdown.Markdown.convert].
         """
+        self.last_run = time.time()
         self.htmlStash.reset()
         self.references.clear()
 

markdown/extensions/legacy_em.py

@@ -14,29 +14,7 @@
 from __future__ import annotations
 
 from . import Extension
-from ..inlinepatterns import UnderscoreProcessor, EmStrongItem, EM_STRONG2_RE, STRONG_EM2_RE
-import re
-
-# _emphasis_
-EMPHASIS_RE = r'(_)([^_]+)\1'
-
-# __strong__
-STRONG_RE = r'(_{2})(.+?)\1'
-
-# __strong_em___
-STRONG_EM_RE = r'(_)\1(?!\1)([^_]+?)\1(?!\1)(.+?)\1{3}'
-
-
-class LegacyUnderscoreProcessor(UnderscoreProcessor):
-    """Emphasis processor for handling strong and em matches inside underscores."""
-
-    PATTERNS = [
-        EmStrongItem(re.compile(EM_STRONG2_RE, re.DOTALL | re.UNICODE), 'double', 'strong,em'),
-        EmStrongItem(re.compile(STRONG_EM2_RE, re.DOTALL | re.UNICODE), 'double', 'em,strong'),
-        EmStrongItem(re.compile(STRONG_EM_RE, re.DOTALL | re.UNICODE), 'double2', 'strong,em'),
-        EmStrongItem(re.compile(STRONG_RE, re.DOTALL | re.UNICODE), 'single', 'strong'),
-        EmStrongItem(re.compile(EMPHASIS_RE, re.DOTALL | re.UNICODE), 'single', 'em')
-    ]
+from ..inlinepatterns import DelimiterProcessor
 
 
 class LegacyEmExtension(Extension):
@@ -45,13 +23,13 @@ class LegacyEmExtension(Extension):
     def extendMarkdown(self, md):
         """ Register the processor.
 
-        | Class Instance                                                | Registry                                                         | Name   | Priority |
-        | ------------------------------------------------------------- | ---------------------------------------------------------------- | ------ | :------: |
-        | [`LegacyUnderscoreProcessor`][markdown.extensions.legacy_em.LegacyUnderscoreProcessor] | [`inlinepatterns`][markdown.inlinepatterns.build_inlinepatterns] | `em_strong2` | `50` |
+        | Class Instance                                                     | Registry                                                         | Name         | Priority |
+        | ------------------------------------------------------------------ | ---------------------------------------------------------------- | ------------ | :------: |
+        | [`DelimiterProcessor`][markdown.inlinepatterns.DelimiterProcessor] | [`inlinepatterns`][markdown.inlinepatterns.build_inlinepatterns] | `em_strong2` | `50`     |
 
         """
-        # flake8: noqa: E501 48-50
-        md.inlinePatterns.register(LegacyUnderscoreProcessor(r'_'), 'em_strong2', 50)
+        # flake8: noqa: E501 27-29
+        md.inlinePatterns.register(DelimiterProcessor(r'_', 'strong,em', md), 'em_strong2', 50)
 
 
 def makeExtension(**kwargs):  # pragma: no cover