From 28a9a0390ec8e05c732410f0b0678466a7280b16 Mon Sep 17 00:00:00 2001
From: Shakthi Kannan <author@shakthimaan.com>
Date: Wed, 30 Dec 2015 11:50:20 +0530
Subject: [PATCH] Document Lisp mode fontification for strings after
 documentation

---
 etc/NEWS                     | 5 +++++
 lisp/emacs-lisp/lisp-mode.el | 8 ++++++++
 2 files changed, 13 insertions(+)

diff --git a/etc/NEWS b/etc/NEWS
index 2788f5c..2f33cdb 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -631,7 +631,12 @@ respectively, `show-paren-when-point-inside-paren' or
 `show-paren-when-point-in-periphery'.
 
 ** Lisp mode
+
+---
 *** Strings after `:documentation' are highlighted as docstrings.
+This enhances Lisp mode fontification to handle documentation of the
+form (:documentation "the doc string") used in Common Lisp code for
+CLOS class and slot documentation.
 
 ** Rectangle editing
 *** Rectangle Mark mode can have corners past EOL or in the middle of a TAB.
diff --git a/lisp/emacs-lisp/lisp-mode.el b/lisp/emacs-lisp/lisp-mode.el
index 9ce0dfd..231b33f 100644
--- a/lisp/emacs-lisp/lisp-mode.el
+++ b/lisp/emacs-lisp/lisp-mode.el
@@ -486,6 +486,9 @@ lisp-cl-font-lock-keywords
   "Default expressions to highlight in Lisp modes.")
 
 (defun lisp-string-in-doc-position-p (listbeg startpos)
+   "Return true if STARTPOS is a position inside a list where a
+docstring may occur.  LISTBEG is the position of the start of the
+innermost list containing STARTPOS."
   (let* ((firstsym (and listbeg
                         (save-excursion
                           (goto-char listbeg)
@@ -516,6 +519,9 @@ lisp-string-in-doc-position-p
                 (= (point) startpos))))))
 
 (defun lisp-string-after-doc-keyword-p (listbeg startpos)
+  "Return true if STARTPOS is a position inside a list right
+after a :documentation symbol.  LISTBEG is the position of the
+start of the innermost list containing STARTPOS."
   (and listbeg                          ; We are inside a Lisp form.
        (save-excursion
          (goto-char startpos)
@@ -524,6 +530,8 @@ lisp-string-after-doc-keyword-p
                   (looking-at ":documentation\\_>"))))))
 
 (defun lisp-font-lock-syntactic-face-function (state)
+  "Return the Lisp font lock syntactic face function for the
+position represented by STATE, a `parse-partial-sexp' state."
   (if (nth 3 state)
       ;; This might be a (doc)string or a |...| symbol.
       (let ((startpos (nth 8 state)))
-- 
2.1.4