From 418d046a5cabcbf0e572e6236d018ced7a531e19 Mon Sep 17 00:00:00 2001
From: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Date: Tue, 27 Oct 2026 15:26:28 +0200
Subject: [PATCH] PEP 813: Add custom lexer

---
 pep_sphinx_extensions/lexers/pep813_lexer.py | 50 ++++++++++++++++++++
 peps/pep-0813.rst                            | 30 ++++--------
 2 files changed, 60 insertions(+), 20 deletions(-)
 create mode 100644 pep_sphinx_extensions/lexers/pep813_lexer.py

diff --git a/pep_sphinx_extensions/lexers/pep813_lexer.py b/pep_sphinx_extensions/lexers/pep813_lexer.py
new file mode 100644
index 00000000000..0a4bf2859ed
--- /dev/null
+++ b/pep_sphinx_extensions/lexers/pep813_lexer.py
@@ -0,0 +1,50 @@
+# This file is placed in the public domain or under the
+# CC0-1.0-Universal license, whichever is more permissive.
+
+"""Custom lexer for PEP 813."""
+
+# This lexer is most useful while PEP 813 is being discussed.
+# If it breaks in the future, it can be safely replaced by plain
+# Python or text lexers.
+
+from pygments.lexer import DelegatingLexer, inherit
+from pygments.lexers.python import (
+    PythonLexer,
+    PythonTracebackLexer,
+    _PythonConsoleLexerBase,
+)
+from pygments.token import Other, String
+
+
+class Py813Lexer(PythonLexer):
+    name = "py813"
+
+    tokens = {
+        "expr-inside-fstring": [
+            # The ``!p`` conversion, without a format specifier
+            (r"(=\s*)?(\!p)\}", String.Interpol, "#pop"),
+            # The ``!p`` conversion, with a format specifier
+            (r"(=\s*)?(\!p):", String.Interpol, "#pop"),
+            inherit,
+        ],
+    }
+
+
+class Py813ConsoleLexer(DelegatingLexer):
+    name = "py813-console"
+
+    def __init__(self, **options):
+        pylexer = Py813Lexer
+        tblexer = PythonTracebackLexer
+
+        class _ReplaceInnerCode(DelegatingLexer):
+            def __init__(self, **options):
+                super().__init__(
+                    pylexer, _PythonConsoleLexerBase, Other.Code, **options
+                )
+
+        super().__init__(tblexer, _ReplaceInnerCode, Other.Traceback, **options)
+
+
+def register():
+    return [Py813Lexer, Py813ConsoleLexer]
diff --git a/peps/pep-0813.rst b/peps/pep-0813.rst
index 74eee19bc12..5d115de6d92 100644
--- a/peps/pep-0813.rst
+++ b/peps/pep-0813.rst
@@ -476,8 +476,7 @@ processes the template decides what to do with it:
 
 For example:
 
-.. code-block:: pycon
-   :force:
+.. code-block:: py813-console
 
     >>> from string.templatelib import convert
     >>> basses = ['precision', 'jazz', 'stingray']
@@ -646,8 +645,7 @@ class:
 
 Now let's create a couple of instances and pretty print them:
 
-.. code-block:: pycon
-   :force:
+.. code-block:: py813-console
 
     >>> precision = Bass(4, 'split coil P', active=False)
     >>> stingray = Bass(5, 'humbucker', active=True)
@@ -662,8 +660,7 @@ Now let's create a couple of instances and pretty print them:
 
 For more complex objects, ``!p`` can help make debugging output more readable:
 
-.. code-block:: pycon
-   :force:
+.. code-block:: py813-console
 
     >>> import os
     >>> print(os.pathconf_names)
@@ -696,8 +693,7 @@ For more complex objects, ``!p`` can help make debugging output more readable:
 In f-strings, the ``!p`` conversion specifier also accepts a printer, such as a ``pprint.Printer`` with its
 own options:
 
-.. code-block:: pycon
-   :force:
+.. code-block:: py813-console
 
     >>> narrow = pprint.Printer(width=30)
     >>> print(f'{stingray!p:{narrow}}')
@@ -715,8 +711,7 @@ own options:
 
 A printer can also be a plain function that takes the object and returns its lines:
 
-.. code-block:: pycon
-   :force:
+.. code-block:: py813-console
 
     >>> def slappa(da: Bass) -> Iterator[str]:
     ...     yield 'All about that bass'
@@ -726,8 +721,7 @@ A printer can also be a plain function that takes the object and returns its lin
 
 Since tuples are read according to the current section, a positional tuple value needs nothing special:
 
-.. code-block:: pycon
-   :force:
+.. code-block:: py813-console
 
     >>> class Things:
     ...     def __pprint__(self):
@@ -753,8 +747,7 @@ Objects with a ``__pprint__()`` method wrap, however deeply they are nested:
             yield pprint.KWARGS
             yield 'children', self.children, []
 
-.. code-block:: pycon
-   :force:
+.. code-block:: py813-console
 
     >>> tree = Node('root', [Node('left', [Node('leaf')]), Node('right')])
     >>> print(f'{tree!p:{pprint.Printer(width=60)}}')
@@ -781,8 +774,7 @@ A ``Layout`` changes the brackets.  This class prints in the angular form that R
             yield 'pitch', self.pitch
             yield 'beats', self.beats, 1
 
-.. code-block:: pycon
-   :force:
+.. code-block:: py813-console
 
     >>> print(f"{Note('E', beats=2)!p}")
     <Note pitch='E' beats=2>
@@ -808,8 +800,7 @@ for each row:
 
 The default printer ignores the hint, so its output still agrees with ``repr()``:
 
-.. code-block:: pycon
-   :force:
+.. code-block:: py813-console
 
     >>> print(f"{Table(['Bass', 'Strings'], [['Precision', 4], ['Stingray', 5]])!p}")
     Table(headers=['Bass', 'Strings'], rows=[['Precision', 4], ['Stingray', 5]])
@@ -840,8 +831,7 @@ value it wraps degrades gracefully when it reaches a printer that doesn't know a
             yield pprint.DELEGATE
             yield self.value
 
-.. code-block:: pycon
-   :force:
+.. code-block:: py813-console
 
     >>> notes = [Note('E'), Emphasis(Note('A')), Note('D')]
     >>> print(f'{notes!p}')