Stricter regexps for highlighting `foo' in docstrings

Previously, the regexp was greedy, so we would erroneously highlight:

`foo `bar'

as a single symbol. Fixes #87.

3 files changed, 22 insertions, 5 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 94b4aa2..6c4d1b0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,15 +2,17 @@
 
 Added imenu support! You can now navigate between headings with imenu.
 
-Helpful now correctly handles \= escapes in docstrings.
+Better handling of docstrings:
+
+* Correctly handle \= escapes
+* Quoted keywords are now highlighted
+* Correctly highlight docstrings that contain standalone `` ` ``
 
 Added disassemble buttons to byte-code functions in symbol properties.
 
 Fixed an issue with the prompt when setting variables to symbol
 values.
 
-Quoted keywords in docstrings are now highlighted.
-
 Smarter handling of keybindings:
 
 * Consider all keymaps, not just `foo-mode-map`.
diff --git a/helpful.el b/helpful.el
index 39ebd32..7d78a38 100644
--- a/helpful.el
+++ b/helpful.el
@@ -545,7 +545,10 @@ blank line afterwards."
   (replace-regexp-in-string
    ;; Replace all text of the form `foo'.
    (rx "`"
-       (group ":" symbol-start (+? anything) symbol-end)
+       (group ":"
+              symbol-start
+              (+? (or (syntax word) (syntax symbol)))
+              symbol-end)
        "'")
    (lambda (it)
      (propertize (match-string 1 it)
@@ -557,7 +560,7 @@ blank line afterwards."
   "Convert symbol references in docstrings to buttons."
   (replace-regexp-in-string
    ;; Replace all text of the form `foo'.
-   (rx "`" symbol-start (+? anything) symbol-end "'")
+   (rx "`" symbol-start (+? (not (any "`" "'"))) symbol-end "'")
    (lambda (it)
      (let* ((sym-name
              (s-chop-prefix "`" (s-chop-suffix "'" it)))
diff --git a/test/unit-test.el b/test/unit-test.el
index db75500..2579316 100644
--- a/test/unit-test.el
+++ b/test/unit-test.el
@@ -27,6 +27,18 @@
     (helpful--docstring #'test-foo t)
     "Docstring here.")))
 
+(ert-deftest helpful--docstring-symbol ()
+  "Correctly handle quotes around symbols."
+  ;; We should replace quoted symbols with links, so the punctuation
+  ;; should not be in the output.
+  (let* ((formatted-docstring (helpful--format-docstring "`message'")))
+    (should
+     (equal formatted-docstring "message")))
+  ;; We should handle stray backquotes.
+  (let* ((formatted-docstring (helpful--format-docstring "`foo `message'")))
+    (should
+     (equal formatted-docstring "`foo message"))))
+
 (ert-deftest helpful--docstring-unescape ()
   "Discard \\=\\= in docstrings."
   (let* ((docstring (helpful--docstring #'apply t))