Merge FFAP's URI-detection code into thingatpt.el.

* lisp/ffap.el: Require thingatpt.
(ffap-url-at-point): Delegate URI detection to thing-at-point.
All URI-valid characters are now recognized.
(ffap-string-at-point): Use use-region-p.
(ffap-url-regexp): Extra character is handled by thing-at-point.
(ffap-string-at-point-mode-alist): Allow parentheses.
(ffap-newsgroup-regexp, ffap-newsgroup-heads, ffap-newsgroup-p):
Convert to aliases; code moved to thingatpt.el.
(ffap-gnus-hook): Use setq-local.

* lisp/thingatpt.el: Rewrite the URL detection routines, absorbing some
code from ffap.el.
(thing-at-point-beginning-of-url-regexp): New var.
(thing-at-point-uri-schemes): Update list of URI schemes.
(thing-at-point-url-regexp): Variable deleted.
(thing-at-point-markedup-url-regexp): Disallow newlines.
(thing-at-point-newsgroup-regexp)
(thing-at-point-newsgroup-heads)
(thing-at-point-default-mail-uri-scheme): New variables.
(thing-at-point-bounds-of-url-at-point): Rewrite.  Use ffap's
method to find the possible bounds of the URI at point.  New
optional argument to find ill-formed URIs.
(thing-at-point-url-at-point): Rewrite.  New arguments for finding
ill-formed URIs.  Use thing-at-point-bounds-of-url-at-point, and
the scheme-adding heuristics from ffap-url-at-point.
(thing-at-point--bounds-of-well-formed-url): New function.  Do
parens matching to decide whether to include parens in the URI

* test/automated/thingatpt.el: New file.

Fixes: debbugs:5673

5 files changed, 362 insertions, 171 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index b43b7bc61d1..9a7a48b186a 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,34 @@
+2013-02-04  Chong Yidong  <cyd@gnu.org>
+
+        * thingatpt.el: Rewrite the URL detection routines, absorbing some
+        code from ffap.el.
+        (thing-at-point-beginning-of-url-regexp): New var.
+        (thing-at-point-uri-schemes): Update list of URI schemes.
+        (thing-at-point-url-regexp): Variable deleted.
+        (thing-at-point-markedup-url-regexp): Disallow newlines.
+        (thing-at-point-newsgroup-regexp)
+        (thing-at-point-newsgroup-heads)
+        (thing-at-point-default-mail-uri-scheme): New variables.
+        (thing-at-point-bounds-of-url-at-point): Rewrite.  Use ffap's
+        method to find the possible bounds of the URI at point.  New
+        optional argument to find ill-formed URIs.
+        (thing-at-point-url-at-point): Rewrite.  New arguments for finding
+        ill-formed URIs.  Use thing-at-point-bounds-of-url-at-point, and
+        the scheme-adding heuristics from ffap-url-at-point.
+        (thing-at-point--bounds-of-well-formed-url): New function.  Do
+        parens matching to decide whether to include parens in the URI
+        (Bug#9153).
+
+        * ffap.el: Require thingatpt.
+        (ffap-url-at-point): Delegate URI detection to thing-at-point.
+        All URI-valid characters are now recognized (Bug#5673).
+        (ffap-string-at-point): Use use-region-p.
+        (ffap-url-regexp): Extra character is handled by thing-at-point.
+        (ffap-string-at-point-mode-alist): Allow parentheses.
+        (ffap-newsgroup-regexp, ffap-newsgroup-heads, ffap-newsgroup-p):
+        Convert to aliases; code moved to thingatpt.el.
+        (ffap-gnus-hook): Use setq-local.
+
 2013-02-04  Glenn Morris  <rgm@gnu.org>
 
         * emacs-lisp/ert.el (ert--explain-format-atom):
diff --git a/lisp/ffap.el b/lisp/ffap.el
index c5b0784e5a2..0769469cbf2 100644
--- a/lisp/ffap.el
+++ b/lisp/ffap.el
@@ -106,6 +106,7 @@
 ;;; Code:
 
 (require 'url-parse)
+(require 'thingatpt)
 
 (define-obsolete-variable-alias 'ffap-version 'emacs-version "23.2")
 
@@ -178,16 +179,14 @@ Note this name may be omitted if it equals the default
   :group 'ffap)
 
 (defvar ffap-url-regexp
-  ;; Could just use `url-nonrelative-link' of w3, if loaded.
-  ;; This regexp is not exhaustive, it just matches common cases.
   (concat
    "\\("
    "news\\(post\\)?:\\|mailto:\\|file:" ; no host ok
    "\\|"
    "\\(ftp\\|https?\\|telnet\\|gopher\\|www\\|wais\\)://" ; needs host
-   "\\)."                               ; require one more character
-   )
-   "Regexp matching URLs.  Use nil to disable URL features in ffap.")
+   "\\)")
+  "Regexp matching the beginning of a URI, for FFAP.
+If the value is nil, disable URL-matching features in ffap.")
 
 (defcustom ffap-foo-at-bar-prefix "mailto"
   "Presumed URL prefix type of strings like \"<foo.9z@bar>\".
@@ -571,38 +570,9 @@ Looks at `ffap-ftp-default-user', returns \"\" for \"localhost\"."
    (ffap-ftp-regexp (ffap-host-to-filename mach))
    ))
 
-(defvar ffap-newsgroup-regexp "^[[:lower:]]+\\.[-+[:lower:]_0-9.]+$"
-  "Strings not matching this fail `ffap-newsgroup-p'.")
-(defvar ffap-newsgroup-heads            ; entirely inadequate
-  '("alt" "comp" "gnu" "misc" "news" "sci" "soc" "talk")
-  "Used by `ffap-newsgroup-p' if gnus is not running.")
-
-(defun ffap-newsgroup-p (string)
-  "Return STRING if it looks like a newsgroup name, else nil."
-  (and
-   (string-match ffap-newsgroup-regexp string)
-   (let ((htbs '(gnus-active-hashtb gnus-newsrc-hashtb gnus-killed-hashtb))
-         (heads ffap-newsgroup-heads)
-         htb ret)
-     (while htbs
-       (setq htb (car htbs) htbs (cdr htbs))
-       (condition-case nil
-           (progn
-             ;; errs: htb symbol may be unbound, or not a hash-table.
-             ;; gnus-gethash is just a macro for intern-soft.
-             (and (symbol-value htb)
-                  (intern-soft string (symbol-value htb))
-                  (setq ret string htbs nil))
-             ;; If we made it this far, gnus is running, so ignore "heads":
-             (setq heads nil))
-         (error nil)))
-     (or ret (not heads)
-         (let ((head (string-match "\\`\\([[:lower:]]+\\)\\." string)))
-           (and head (setq head (substring string 0 (match-end 1)))
-                (member head heads)
-                (setq ret string))))
-     ;; Is there ever a need to modify string as a newsgroup name?
-     ret)))
+(defvaralias 'ffap-newsgroup-regexp 'thing-at-point-newsgroup-regexp)
+(defvaralias 'ffap-newsgroup-heads  'thing-at-point-newsgroup-heads)
+(defalias 'ffap-newsgroup-p 'thing-at-point-newsgroup-p)
 
 (defsubst ffap-url-p (string)
   "If STRING looks like an URL, return it (maybe improved), else nil."
@@ -1017,7 +987,7 @@ If a given RFC isn't in these then `ffap-rfc-path' is offered."
     ;; * no commas (good for latex)
     (file "--:\\\\$+<>@-Z_[:alpha:]~*?" "<@" "@>;.,!:")
     ;; An url, or maybe a email/news message-id:
-    (url "--:=&?$+@-Z_[:alpha:]~#,%;*" "^[:alnum:]" ":;.,!?")
+    (url "--:=&?$+@-Z_[:alpha:]~#,%;*()!'" "^[0-9a-zA-Z]" ":;.,!?")
     ;; Find a string that does *not* contain a colon:
     (nocolon "--9$+<>@-Z_[:alpha:]~" "<@" "@>;.,!?")
     ;; A machine:
@@ -1031,7 +1001,7 @@ possibly a major-mode name, or one of the symbol
 Function `ffap-string-at-point' uses the data fields as follows:
 1. find a maximal string of CHARS around point,
 2. strip BEG chars before point from the beginning,
-3. Strip END chars after point from the end.")
+3. strip END chars after point from the end.")
 
 (defvar ffap-string-at-point nil
   ;; Added at suggestion of RHOGEE (for ff-paths), 7/24/95.
@@ -1050,22 +1020,22 @@ Sets the variable `ffap-string-at-point' and the variable
            (or (assq (or mode major-mode) ffap-string-at-point-mode-alist)
                (assq 'file ffap-string-at-point-mode-alist))))
          (pt (point))
-         (str
-          (if (and transient-mark-mode mark-active)
-              (buffer-substring
-               (setcar ffap-string-at-point-region (region-beginning))
-               (setcar (cdr ffap-string-at-point-region) (region-end)))
-            (buffer-substring
-             (save-excursion
-               (skip-chars-backward (car args))
-               (skip-chars-forward (nth 1 args) pt)
-               (setcar ffap-string-at-point-region (point)))
-             (save-excursion
-               (skip-chars-forward (car args))
-               (skip-chars-backward (nth 2 args) pt)
-               (setcar (cdr ffap-string-at-point-region) (point)))))))
-    (set-text-properties 0 (length str) nil str)
-    (setq ffap-string-at-point str)))
+         (beg (if (use-region-p)
+                  (region-beginning)
+                (save-excursion
+                  (skip-chars-backward (car args))
+                  (skip-chars-forward (nth 1 args) pt)
+                  (point))))
+         (end (if (use-region-p)
+                  (region-end)
+                (save-excursion
+                  (skip-chars-forward (car args))
+                  (skip-chars-backward (nth 2 args) pt)
+                  (point)))))
+    (setq ffap-string-at-point
+          (buffer-substring-no-properties
+           (setcar ffap-string-at-point-region beg)
+           (setcar (cdr ffap-string-at-point-region) end)))))
 
 (defun ffap-string-around ()
   ;; Sometimes useful to decide how to treat a string.
@@ -1098,35 +1068,15 @@ Assumes the buffer has not changed."
 
 (defun ffap-url-at-point ()
   "Return URL from around point if it exists, or nil."
-  ;; Could use w3's url-get-url-at-point instead.  Both handle "URL:",
-  ;; ignore non-relative links, trim punctuation.  The other will
-  ;; actually look back if point is in whitespace, but I would rather
-  ;; ffap be less aggressive in such situations.
   (when ffap-url-regexp
     (or (and (eq major-mode 'w3-mode) ; In a w3 buffer button?
              (w3-view-this-url t))
-        ;; Is there a reason not to strip trailing colon?
-        (let ((name (ffap-string-at-point 'url)))
-          (cond
-           ((string-match "^url:" name) (setq name (substring name 4)))
-           ((and (string-match "\\`[^:</>@]+@[^:</>@]+[[:alnum:]]\\'" name)
-                 ;; "foo@bar": could be "mailto" or "news" (a Message-ID).
-                 ;; Without "<>" it must be "mailto".  Otherwise could be
-                 ;; either, so consult `ffap-foo-at-bar-prefix'.
-                 (let ((prefix (if (and (equal (ffap-string-around) "<>")
-                                        ;; Expect some odd characters:
-                                        (string-match "[$.0-9].*[$.0-9].*@" name))
-                                   ;; Could be news:
-                                   ffap-foo-at-bar-prefix
-                                 "mailto")))
-                   (and prefix (setq name (concat prefix ":" name))))))
-           ((ffap-newsgroup-p name) (setq name (concat "news:" name)))
-           ((and (string-match "\\`[[:alnum:]]+\\'" name) ; <mic> <root> <nobody>
-                 (equal (ffap-string-around) "<>")
-                 ;;     (ffap-user-p name):
-                 (not (string-match "~" (expand-file-name (concat "~" name)))))
-            (setq name (concat "mailto:" name)))
-           ((ffap-url-p name)))))))
+        (let ((thing-at-point-beginning-of-url-regexp ffap-url-regexp)
+              (thing-at-point-default-mail-scheme ffap-foo-at-bar-prefix))
+          (thing-at-point-url-at-point t
+                                       (if (use-region-p)
+                                           (cons (region-beginning)
+                                                 (region-end))))))))
 
 (defvar ffap-gopher-regexp
   "^.*\\<\\(Type\\|Name\\|Path\\|Host\\|Port\\) *= *\\(.*\\) *$"
@@ -1763,7 +1713,8 @@ Only intended for interactive use."
 
 (defun ffap-gnus-hook ()
   "Bind `ffap-gnus-next' and `ffap-gnus-menu' to M-l and M-m, resp."
-  (set (make-local-variable 'ffap-foo-at-bar-prefix) "news") ; message-id's
+  ;; message-id's
+  (setq-local thing-at-point-default-mail-uri-scheme "news")
   ;; Note "l", "L", "m", "M" are taken:
   (local-set-key "\M-l" 'ffap-gnus-next)
   (local-set-key "\M-m" 'ffap-gnus-menu))
diff --git a/lisp/thingatpt.el b/lisp/thingatpt.el
index e1e3e8e1e46..9526cb76e74 100644
--- a/lisp/thingatpt.el
+++ b/lisp/thingatpt.el
@@ -232,7 +232,7 @@ The bounds of THING are determined by `bounds-of-thing-at-point'."
 (put 'defun 'end-op       'end-of-defun)
 (put 'defun 'forward-op   'end-of-defun)
 
-;;  Filenames and URLs  www.com/foo%32bar
+;;  Filenames
 
 (defvar thing-at-point-file-name-chars "-~/[:alnum:]_.${}#%,:"
   "Characters allowable in filenames.")
@@ -248,94 +248,224 @@ The bounds of THING are determined by `bounds-of-thing-at-point'."
            (forward-char)
          (goto-char (point-min)))))
 
+;;  URIs
+
+(defvar thing-at-point-beginning-of-url-regexp nil
+  "Regexp matching the beginning of a well-formed URI.
+If nil, construct the regexp from `thing-at-point-uri-schemes'.")
+
 (defvar thing-at-point-url-path-regexp
   "[^]\t\n \"'<>[^`{}]*[^]\t\n \"'<>[^`{}.,;]+"
-  "A regular expression probably matching the host and filename or e-mail part of a URL.")
+  "Regexp matching the host and filename or e-mail part of a URL.")
 
 (defvar thing-at-point-short-url-regexp
   (concat "[-A-Za-z0-9]+\\.[-A-Za-z0-9.]+" thing-at-point-url-path-regexp)
-  "A regular expression probably matching a URL without an access scheme.
-Hostname matching is stricter in this case than for
-``thing-at-point-url-regexp''.")
+  "Regexp matching a URI without a scheme component.")
 
 (defvar thing-at-point-uri-schemes
   ;; Officials from http://www.iana.org/assignments/uri-schemes.html
-  '("ftp://" "http://" "gopher://" "mailto:" "news:" "nntp:"
-    "telnet://" "wais://" "file:/" "prospero:" "z39.50s:" "z39.50r:"
-    "cid:" "mid:" "vemmi:" "service:" "imap:" "nfs:" "acap:" "rtsp:"
-    "tip:" "pop:" "data:" "dav:" "opaquelocktoken:" "sip:" "tel:" "fax:"
-    "modem:" "ldap:" "https://" "soap.beep:" "soap.beeps:" "urn:" "go:"
-    "afs:" "tn3270:" "mailserver:"
-    "crid:" "dict:" "dns:" "dtn:" "h323:" "im:" "info:" "ipp:"
-    "iris.beep:" "mtqp:" "mupdate:" "pres:" "sips:" "snmp:" "tag:"
-    "tftp:" "xmlrpc.beep:" "xmlrpc.beeps:" "xmpp:"
-  ;; Compatibility
-    "snews:" "irc:" "mms://" "mmsh://")
-  "Uniform Resource Identifier (URI) Schemes.")
-
-(defvar thing-at-point-url-regexp
-  (concat "\\<\\(" (mapconcat 'identity thing-at-point-uri-schemes "\\|") "\\)"
-          thing-at-point-url-path-regexp)
-  "A regular expression probably matching a complete URL.")
-
-(defvar thing-at-point-markedup-url-regexp
-  "<URL:[^>]+>"
-  "A regular expression matching a URL marked up per RFC1738.
-This may contain whitespace (including newlines) .")
+  '("aaa://" "about:" "acap://" "apt:" "bzr://" "bzr+ssh://"
+    "attachment:/" "chrome://" "cid:" "content://" "crid://" "cvs://"
+    "data:" "dav:" "dict://" "doi:" "dns:" "dtn:" "feed:" "file:/"
+    "finger://" "fish://" "ftp://" "geo:" "git://" "go:" "gopher://"
+    "h323:" "http://" "https://" "im:" "imap://" "info:" "ipp:"
+    "irc://" "irc6://" "ircs://" "iris.beep:" "jar:" "ldap://"
+    "ldaps://" "mailto:" "mid:"  "mtqp://" "mupdate://" "news:"
+    "nfs://" "nntp://" "opaquelocktoken:" "pop://" "pres:"
+    "resource://" "rmi://" "rsync://" "rtsp://" "rtspu://" "service:"
+    "sftp://" "sip:" "sips:" "smb://" "sms:" "snmp://" "soap.beep://"
+    "soap.beeps://" "ssh://" "svn://" "svn+ssh://" "tag:" "tel:"
+    "telnet://" "tftp://" "tip://" "tn3270://" "udp://" "urn:"
+    "uuid:" "vemmi://"  "webcal://" "xri://" "xmlrpc.beep://"
+    "xmlrpc.beeps://" "z39.50r://" "z39.50s://" "xmpp:"
+    ;; Compatibility
+    "fax:" "mms://" "mmsh://" "modem:" "prospero:" "snews:"
+    "wais://")
+  "List of URI schemes recognized by `thing-at-point-url-at-point'.
+Each string in this list should correspond to the start of a
+URI's scheme component, up to and including the trailing // if
+the scheme calls for that to be present.")
+
+(defvar thing-at-point-markedup-url-regexp "<URL:\\([^<>\n]+\\)>"
+  "Regexp matching a URL marked up per RFC1738.
+This kind of markup was formerly recommended as a way to indicate
+URIs, but as of RFC 3986 it is no longer recommended.
+Subexpression 1 should contain the delimited URL.")
+
+(defvar thing-at-point-newsgroup-regexp
+  "\\`[[:lower:]]+\\.[-+[:lower:]_0-9.]+\\'"
+  "Regexp matching a newsgroup name.")
+
+(defvar thing-at-point-newsgroup-heads
+  '("alt" "comp" "gnu" "misc" "news" "sci" "soc" "talk")
+  "Used by `thing-at-point-newsgroup-p' if gnus is not running.")
+
+(defvar thing-at-point-default-mail-uri-scheme "mailto"
+  "Default scheme for ill-formed URIs that look like <foo@example.com>.
+If nil, do not give such URIs a scheme.")
 
 (put 'url 'bounds-of-thing-at-point 'thing-at-point-bounds-of-url-at-point)
-(defun thing-at-point-bounds-of-url-at-point ()
-  (let ((strip (thing-at-point-looking-at
-                         thing-at-point-markedup-url-regexp))) ;; (url "") short
-    (if (or strip
-            (thing-at-point-looking-at thing-at-point-url-regexp)
-            ;; Access scheme omitted?
-            ;; (setq short (thing-at-point-looking-at
-            ;;           thing-at-point-short-url-regexp))
-            )
-        (let ((beginning (match-beginning 0))
-              (end (match-end 0)))
-          (when strip
-            (setq beginning (+ beginning 5))
-            (setq end (- end 1)))
-          (cons beginning end)))))
+
+(defun thing-at-point-bounds-of-url-at-point (&optional lax)
+  "Return a cons cell containing the start and end of the URI at point.
+Try to find a URI using `thing-at-point-markedup-url-regexp'.
+If that fails, try with `thing-at-point-beginning-of-url-regexp'.
+If that also fails, and optional argument LAX is non-nil, return
+the bounds of a possible ill-formed URI (one lacking a scheme)."
+  ;; Look for the old <URL:foo> markup.  If found, use it.
+  (or (thing-at-point--bounds-of-markedup-url)
+      ;; Otherwise, find the bounds within which a URI may exist.  The
+      ;; method is similar to `ffap-string-at-point'.  Note that URIs
+      ;; may contain parentheses but may not contain spaces (RFC3986).
+      (let* ((allowed-chars "--:=&?$+@-Z_[:alpha:]~#,%;*()!'")
+             (skip-before "^[0-9a-zA-Z]")
+             (skip-after  ":;.,!?")
+             (pt (point))
+             (beg (save-excursion
+                    (skip-chars-backward allowed-chars)
+                    (skip-chars-forward skip-before pt)
+                    (point)))
+             (end (save-excursion
+                    (skip-chars-forward allowed-chars)
+                    (skip-chars-backward skip-after pt)
+                    (point))))
+        (or (thing-at-point--bounds-of-well-formed-url beg end pt)
+            (if lax (cons beg end))))))
+
+(defun thing-at-point--bounds-of-markedup-url ()
+  (when thing-at-point-markedup-url-regexp
+    (let ((case-fold-search t)
+          (pt (point))
+          (beg (line-beginning-position))
+          (end (line-end-position))
+          found)
+      (save-excursion
+        (goto-char beg)
+        (while (and (not found)
+                    (<= (point) pt)
+                    (< (point) end))
+          (and (re-search-forward thing-at-point-markedup-url-regexp
+                                  end 1)
+               (> (point) pt)
+               (setq found t))))
+      (if found
+          (cons (match-beginning 1) (match-end 1))))))
+
+(defun thing-at-point--bounds-of-well-formed-url (beg end pt)
+  (save-excursion
+    (goto-char beg)
+    (let (url-beg paren-end regexp)
+      (save-restriction
+        (narrow-to-region beg end)
+        ;; The scheme component must either match at BEG, or have no
+        ;; other alphanumerical ASCII characters before it.
+        (setq regexp (concat "\\(?:\\`\\|[^a-zA-Z0-9]\\)\\("
+                             (or thing-at-point-beginning-of-url-regexp
+                                 (regexp-opt thing-at-point-uri-schemes))
+                             "\\)"))
+        (and (re-search-forward regexp end t)
+             ;; URI must have non-empty contents.
+             (< (point) end)
+             (setq url-beg (match-beginning 1))))
+      (when url-beg
+        ;; If there is an open paren before the URI, truncate to the
+        ;; matching close paren.
+        (and (> url-beg (point-min))
+             (eq (car-safe (syntax-after (1- url-beg))) 4)
+             (save-restriction
+               (narrow-to-region (1- url-beg) (min end (point-max)))
+               (setq paren-end (ignore-errors
+                                 (scan-lists (1- url-beg) 1 0))))
+             (not (blink-matching-check-mismatch (1- url-beg) paren-end))
+             (setq end (1- paren-end)))
+        (cons url-beg end)))))
 
 (put 'url 'thing-at-point 'thing-at-point-url-at-point)
-(defun thing-at-point-url-at-point ()
-  "Return the URL around or before point.
 
-Search backwards for the start of a URL ending at or after point.  If
-no URL found, return nil.  The access scheme will be prepended if
-absent: \"mailto:\" if the string contains \"@\", \"ftp://\" if it
-starts with \"ftp\" and not \"ftp:/\", or \"http://\" by default."
-
-  (let ((url "") short strip)
-    (if (or (setq strip (thing-at-point-looking-at
-                         thing-at-point-markedup-url-regexp))
-            (thing-at-point-looking-at thing-at-point-url-regexp)
-            ;; Access scheme omitted?
-            (setq short (thing-at-point-looking-at
-                         thing-at-point-short-url-regexp)))
-        (progn
-          (setq url (buffer-substring-no-properties (match-beginning 0)
-                                                    (match-end 0)))
-          (and strip (setq url (substring url 5 -1))) ; Drop "<URL:" & ">"
-          ;; strip whitespace
-          (while (string-match "[ \t\n\r]+" url)
-            (setq url (replace-match "" t t url)))
-          (and short (setq url (concat (cond ((string-match "^[a-zA-Z]+:" url)
-                                               ;; already has a URL scheme.
-                                               "")
-                                             ((string-match "@" url)
-                                              "mailto:")
-                                             ;; e.g. ftp.swiss... or ftp-swiss...
-                                             ((string-match "^ftp" url)
-                                              "ftp://")
-                                             (t "http://"))
-                                       url)))
-          (if (string-equal "" url)
-              nil
-            url)))))
+(defun thing-at-point-url-at-point (&optional lax bounds)
+  "Return the URL around or before point.
+If no URL is found, return nil.
+
+If optional argument LAX is non-nil, look for URLs that are not
+well-formed, such as foo@bar or <nobody>.
+
+If optional arguments BOUNDS are non-nil, it should be a cons
+cell of the form (START . END), containing the beginning and end
+positions of the URI.  Otherwise, these positions are detected
+automatically from the text around point.
+
+If the scheme component is absent, either because a URI delimited
+with <url:...> lacks one, or because an ill-formed URI was found
+with LAX or BEG and END, try to add a scheme in the returned URI.
+The scheme is chosen heuristically: \"mailto:\" if the address
+looks like an email address, \"ftp://\" if it starts with
+\"ftp\", etc."
+  (unless bounds
+    (setq bounds (thing-at-point-bounds-of-url-at-point lax)))
+  (when (and bounds (< (car bounds) (cdr bounds)))
+    (let ((str (buffer-substring-no-properties (car bounds) (cdr bounds))))
+      ;; If there is no scheme component, try to add one.
+      (unless (string-match "\\`[a-zA-Z][-a-zA-Z0-9+.]*:" str)
+        (or
+         ;; If the URI has the form <foo@bar>, treat it according to
+         ;; `thing-at-point-default-mail-uri-scheme'.  If there are
+         ;; no angle brackets, it must be mailto.
+         (when (string-match "\\`[^:</>@]+@[-.0-9=&?$+A-Z_a-z~#,%;*]" str)
+           (let ((scheme (if (and (eq (char-before (car bounds)) ?<)
+                                  (eq (char-after  (cdr bounds)) ?>))
+                             thing-at-point-default-mail-uri-scheme
+                           "mailto")))
+             (if scheme
+                 (setq str (concat scheme ":" str)))))
+         ;; If the string is like <FOO>, where FOO is an existing user
+         ;; name on the system, treat that as an email address.
+         (and (string-match "\\`[[:alnum:]]+\\'" str)
+              (eq (char-before (car bounds)) ?<)
+              (eq (char-after  (cdr bounds)) ?>)
+              (not (string-match "~" (expand-file-name (concat "~" str))))
+              (setq str (concat "mailto:" str)))
+         ;; If it looks like news.example.com, treat it as news.
+         (if (thing-at-point-newsgroup-p str)
+             (setq str (concat "news:" str)))
+         ;; If it looks like ftp.example.com. treat it as ftp.
+         (if (string-match "\\`ftp\\." str)
+             (setq str (concat "ftp://" str)))
+         ;; If it looks like www.example.com. treat it as http.
+         (if (string-match "\\`www\\." str)
+             (setq str (concat "http://" str)))
+         ;; Otherwise, it just isn't a URI.
+         (setq str nil)))
+      str)))
+
+(defun thing-at-point-newsgroup-p (string)
+  "Return STRING if it looks like a newsgroup name, else nil."
+  (and
+   (string-match thing-at-point-newsgroup-regexp string)
+   (let ((htbs '(gnus-active-hashtb gnus-newsrc-hashtb gnus-killed-hashtb))
+         (heads thing-at-point-newsgroup-heads)
+         htb ret)
+     (while htbs
+       (setq htb (car htbs) htbs (cdr htbs))
+       (condition-case nil
+           (progn
+             ;; errs: htb symbol may be unbound, or not a hash-table.
+             ;; gnus-gethash is just a macro for intern-soft.
+             (and (symbol-value htb)
+                  (intern-soft string (symbol-value htb))
+                  (setq ret string htbs nil))
+             ;; If we made it this far, gnus is running, so ignore "heads":
+             (setq heads nil))
+         (error nil)))
+     (or ret (not heads)
+         (let ((head (string-match "\\`\\([[:lower:]]+\\)\\." string)))
+           (and head (setq head (substring string 0 (match-end 1)))
+                (member head heads)
+                (setq ret string))))
+     ret)))
+
+(put 'url 'end-op (lambda () (end-of-thing 'url)))
+
+(put 'url 'beginning-op (lambda () (end-of-thing 'url)))
 
 ;; The normal thingatpt mechanism doesn't work for complex regexps.
 ;; This should work for almost any regexp wherever we are in the
@@ -372,19 +502,6 @@ point."
         (goto-char match)
         (looking-at regexp)))))
 
-(put 'url 'end-op
-     (lambda ()
-       (let ((bounds (thing-at-point-bounds-of-url-at-point)))
-         (if bounds
-             (goto-char (cdr bounds))
-           (error "No URL here")))))
-(put 'url 'beginning-op
-     (lambda ()
-       (let ((bounds (thing-at-point-bounds-of-url-at-point)))
-         (if bounds
-             (goto-char (car bounds))
-           (error "No URL here")))))
-
 ;;   Email addresses
 (defvar thing-at-point-email-regexp
   "<?[-+_.~a-zA-Z][-+_.~:a-zA-Z0-9]*@[-.a-zA-Z0-9]+>?"
diff --git a/test/ChangeLog b/test/ChangeLog
index 651453566f2..41bb1be190e 100644
--- a/test/ChangeLog
+++ b/test/ChangeLog
@@ -1,3 +1,7 @@
+2013-02-04  Chong Yidong  <cyd@gnu.org>
+
+        * automated/thingatpt.el: New file.
+
 2013-02-03  Chong Yidong  <cyd@gnu.org>
 
         * automated/files.el (file-test--do-local-variables-test): Avoid
diff --git a/test/automated/thingatpt.el b/test/automated/thingatpt.el
new file mode 100644
index 00000000000..f33a8f4b0e6
--- /dev/null
+++ b/test/automated/thingatpt.el
@@ -0,0 +1,88 @@
+;;; thingatpt.el --- tests for thing-at-point.
+
+;; Copyright (C) 2013 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Code:
+
+(require 'ert)
+
+(defvar thing-at-point-test-data
+  '(("http://1.gnu.org" 1  url "http://1.gnu.org")
+    ("http://2.gnu.org" 6 url "http://2.gnu.org")
+    ("http://3.gnu.org" 19 url "http://3.gnu.org")
+    ("https://4.gnu.org" 1  url "https://4.gnu.org")
+    ("bzr://savannah.gnu.org" 1 url "bzr://savannah.gnu.org")
+    ("A geo URI (geo:3.14159,-2.71828)." 12 url "geo:3.14159,-2.71828")
+    ("Visit http://5.gnu.org now." 5 url nil)
+    ("Visit http://6.gnu.org now." 7 url "http://6.gnu.org")
+    ("Visit http://7.gnu.org now." 22 url "http://7.gnu.org")
+    ("Visit http://8.gnu.org now." 22 url "http://8.gnu.org")
+    ("Visit http://9.gnu.org now." 24 url nil)
+    ;; Invalid URIs
+    ("<<<<" 2 url nil)
+    ("<>" 1 url nil)
+    ("<url:>" 1 url nil)
+    ("http://" 1 url nil)
+    ;; Invalid schema
+    ("foo://www.gnu.org" 1 url nil)
+    ("foohttp://www.gnu.org" 1 url nil)
+    ;; Non alphanumeric characters can be found in URIs
+    ("ftp://example.net/~foo!;#bar=baz&goo=bob" 3 url "ftp://example.net/~foo!;#bar=baz&goo=bob")
+    ("bzr+ssh://user@example.net:5/a%20d,5" 34 url "bzr+ssh://user@example.net:5/a%20d,5")
+    ;; <url:...> markup
+    ("Url: <url:foo://1.example.com>..." 8 url "foo://1.example.com")
+    ("Url: <url:foo://2.example.com>..." 30 url "foo://2.example.com")
+    ("Url: <url:foo://www.gnu.org/a bc>..." 20 url "foo://www.gnu.org/a bc")
+    ;; Hack used by thing-at-point: drop punctuation at end of URI.
+    ("Go to http://www.gnu.org, for details" 7 url "http://www.gnu.org")
+    ("Go to http://www.gnu.org." 24 url "http://www.gnu.org")
+    ;; Standard URI delimiters
+    ("Go to \"http://10.gnu.org\"." 8 url "http://10.gnu.org")
+    ("Go to \"http://11.gnu.org/\"." 26 url "http://11.gnu.org/")
+    ("Go to <http://12.gnu.org> now." 8 url "http://12.gnu.org")
+    ("Go to <http://13.gnu.org> now." 24 url "http://13.gnu.org")
+    ;; Parenthesis handling (non-standard)
+    ("http://example.com/a(b)c" 21 url "http://example.com/a(b)c")
+    ("http://example.com/a(b)" 21 url "http://example.com/a(b)")
+    ("(http://example.com/abc)" 2 url "http://example.com/abc")
+    ("This (http://example.com/a(b))" 7 url "http://example.com/a(b)")
+    ("This (http://example.com/a(b))" 30 url "http://example.com/a(b)")
+    ("This (http://example.com/a(b))" 5 url nil)
+    ("http://example.com/ab)c" 4 url "http://example.com/ab)c")
+    ;; URL markup, lacking schema
+    ("<url:foo@example.com>" 1 url "mailto:foo@example.com")
+    ("<url:ftp.example.net/abc/>" 1 url "ftp://ftp.example.net/abc/"))
+  "List of thing-at-point tests.
+Each list element should have the form
+
+  (STRING POS THING RESULT)
+
+where STRING is a string of buffer contents, POS is the value of
+point, THING is a symbol argument for `thing-at-point', and
+RESULT should be the result of calling `thing-at-point' from that
+position to retrieve THING.")
+
+(ert-deftest thing-at-point-tests ()
+  "Test the file-local variables implementation."
+  (dolist (test thing-at-point-test-data)
+    (with-temp-buffer
+      (insert (nth 0 test))
+      (goto-char (nth 1 test))
+      (should (equal (thing-at-point (nth 2 test)) (nth 3 test))))))
+
+;;; thingatpt.el ends here