helpful

commit 9778c0d988d1b7dcc48e7b22b53d80be53451ff5
parent 3698c95359fa45b38f65f08bfa350996f1e91af8
Author: Wilfred Hughes <me@wilfred.me.uk>
Date:   Sat, 16 Dec 2017 12:30:32 +0000

Propertize references to Info nodes

Closes #32

Diffstat:
M
CHANGELOG.md
 | 
2
+-
M
README.md
 | 
3
++-
M
helpful.el
 | 
28
++++++++++++++++++++++++++++

3 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # v0.5
 
-No changes yet.
+Ensure docstring references to Info nodes are converted to buttons.
 
 # v0.4
 
diff --git a/README.md b/README.md
@@ -60,7 +60,8 @@ Helpful will show you where a function is being called!
 Docstrings in helpful:
 
 * Highlight the summary (the first sentence)
-* Include cross-references
+* Include cross-references to other functions/variables
+* Linkify references to Info nodes
 * Hide superfluous punctuation
 
 ![screenshot](screenshots/helpful_view_in_manual.png)
diff --git a/helpful.el b/helpful.el
@@ -348,6 +348,16 @@ or disable if already enabled."
   (let ((sym (button-get button 'symbol)))
     (helpful-symbol sym)))
 
+(define-button-type 'helpful-info-button
+  'action #'helpful--info
+  'info-node nil
+  'follow-link t
+  'help-echo "View this Info node")
+
+(defun helpful--info (button)
+  "Describe the symbol that this BUTTON represents."
+  (info (button-get button 'info-node)))
+
 (defun helpful--split-first-line (docstring)
   "If the first line is a standalone sentence, ensure we have a
 blank line afterwards."
@@ -382,12 +392,30 @@ blank line afterwards."
    docstring
    t t))
 
+(defun helpful--propertize-info (docstring)
+  "Convert info references in docstrings to buttons."
+  (replace-regexp-in-string
+   ;; Replace all text of the form `foo'.
+   (rx "Info node `" (group (+ (not (in "'")))) "'")
+   (lambda (it)
+     ;; info-node has the form "(cl)Loop Facility".
+     (let ((info-node (match-string 1 it)))
+       (concat
+        "Info node "
+        (make-text-button
+         info-node nil
+         :type 'helpful-info-button
+         'info-node info-node))))
+   docstring
+   t t))
+
 ;; TODO: fix upstream Emacs bug that means `-map' is not highlighted
 ;; in the docstring for `--map'.
 (defun helpful--format-docstring (docstring)
   "Replace cross-references with links in DOCSTRING."
   (-> docstring
       (helpful--split-first-line)
+      (helpful--propertize-info)
       (helpful--propertize-symbols)
       (s-trim)))