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;;; thingatpt.el --- get the `thing' at point
;; Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 2000,
;; 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
;; Free Software Foundation, Inc.
;; Author: Mike Williams <mikew@gopher.dosli.govt.nz>
;; Maintainer: FSF
;; Keywords: extensions, matching, mouse
;; Created: Thu Mar 28 13:48:23 1991
;; 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/>.
;;; Commentary:
;; This file provides routines for getting the "thing" at the location of
;; point, whatever that "thing" happens to be. The "thing" is defined by
;; its beginning and end positions in the buffer.
;;
;; The function bounds-of-thing-at-point finds the beginning and end
;; positions by moving first forward to the end of the "thing", and then
;; backwards to the beginning. By default, it uses the corresponding
;; forward-"thing" operator (eg. forward-word, forward-line).
;;
;; Special cases are allowed for using properties associated with the named
;; "thing":
;;
;; forward-op Function to call to skip forward over a "thing" (or
;; with a negative argument, backward).
;;
;; beginning-op Function to call to skip to the beginning of a "thing".
;; end-op Function to call to skip to the end of a "thing".
;;
;; Reliance on existing operators means that many `things' can be accessed
;; without further code: eg.
;; (thing-at-point 'line)
;; (thing-at-point 'page)
;;; Code:
(provide 'thingatpt)
;; Basic movement
;;;###autoload
(defun forward-thing (thing &optional n)
"Move forward to the end of the Nth next THING."
(let ((forward-op (or (get thing 'forward-op)
(intern-soft (format "forward-%s" thing)))))
(if (functionp forward-op)
(funcall forward-op (or n 1))
(error "Can't determine how to move over a %s" thing))))
;; General routines
;;;###autoload
(defun bounds-of-thing-at-point (thing)
"Determine the start and end buffer locations for the THING at point.
THING is a symbol which specifies the kind of syntactic entity you want.
Possibilities include `symbol', `list', `sexp', `defun', `filename', `url',
`email', `word', `sentence', `whitespace', `line', `page' and others.
See the file `thingatpt.el' for documentation on how to define
a symbol as a valid THING.
The value is a cons cell (START . END) giving the start and end positions
of the textual entity that was found."
(if (get thing 'bounds-of-thing-at-point)
(funcall (get thing 'bounds-of-thing-at-point))
(let ((orig (point)))
(condition-case nil
(save-excursion
;; Try moving forward, then back.
(funcall ;; First move to end.
(or (get thing 'end-op)
(lambda () (forward-thing thing 1))))
(funcall ;; Then move to beg.
(or (get thing 'beginning-op)
(lambda () (forward-thing thing -1))))
(let ((beg (point)))
(if (not (and beg (> beg orig)))
;; If that brings us all the way back to ORIG,
;; it worked. But END may not be the real end.
;; So find the real end that corresponds to BEG.
(let ((real-end
(progn
(funcall
(or (get thing 'end-op)
(lambda () (forward-thing thing 1))))
(point))))
(if (and beg real-end (<= beg orig) (<= orig real-end))
(cons beg real-end)))
(goto-char orig)
;; Try a second time, moving backward first and then forward,
;; so that we can find a thing that ends at ORIG.
(funcall ;; First, move to beg.
(or (get thing 'beginning-op)
(lambda () (forward-thing thing -1))))
(funcall ;; Then move to end.
(or (get thing 'end-op)
(lambda () (forward-thing thing 1))))
(let ((end (point))
(real-beg
(progn
(funcall
(or (get thing 'beginning-op)
(lambda () (forward-thing thing -1))))
(point))))
(if (and real-beg end (<= real-beg orig) (<= orig end))
(cons real-beg end))))))
(error nil)))))
;;;###autoload
(defun thing-at-point (thing)
"Return the THING at point.
THING is a symbol which specifies the kind of syntactic entity you want.
Possibilities include `symbol', `list', `sexp', `defun', `filename', `url',
`email', `word', `sentence', `whitespace', `line', `page' and others.
See the file `thingatpt.el' for documentation on how to define
a symbol as a valid THING."
(if (get thing 'thing-at-point)
(funcall (get thing 'thing-at-point))
(let ((bounds (bounds-of-thing-at-point thing)))
(if bounds
(buffer-substring (car bounds) (cdr bounds))))))
;; Go to beginning/end
(defun beginning-of-thing (thing)
(let ((bounds (bounds-of-thing-at-point thing)))
(or bounds (error "No %s here" thing))
(goto-char (car bounds))))
(defun end-of-thing (thing)
(let ((bounds (bounds-of-thing-at-point thing)))
(or bounds (error "No %s here" thing))
(goto-char (cdr bounds))))
;; Special cases
;; Lines
;; bolp will be false when you click on the last line in the buffer
;; and it has no final newline.
(put 'line 'beginning-op
(lambda () (if (bolp) (forward-line -1) (beginning-of-line))))
;; Sexps
(defun in-string-p ()
(let ((orig (point)))
(save-excursion
(beginning-of-defun)
(nth 3 (parse-partial-sexp (point) orig)))))
(defun end-of-sexp ()
(let ((char-syntax (char-syntax (char-after))))
(if (or (eq char-syntax ?\))
(and (eq char-syntax ?\") (in-string-p)))
(forward-char 1)
(forward-sexp 1))))
(put 'sexp 'end-op 'end-of-sexp)
(defun beginning-of-sexp ()
(let ((char-syntax (char-syntax (char-before))))
(if (or (eq char-syntax ?\()
(and (eq char-syntax ?\") (in-string-p)))
(forward-char -1)
(forward-sexp -1))))
(put 'sexp 'beginning-op 'beginning-of-sexp)
;; Lists
(put 'list 'bounds-of-thing-at-point 'thing-at-point-bounds-of-list-at-point)
(defun thing-at-point-bounds-of-list-at-point ()
(save-excursion
(let ((opoint (point))
(beg (condition-case nil
(progn (up-list -1)
(point))
(error nil))))
(condition-case nil
(if beg
(progn (forward-sexp)
(cons beg (point)))
;; Are we are at the beginning of a top-level sexp?
(forward-sexp)
(let ((end (point)))
(backward-sexp)
(if (>= opoint (point))
(cons opoint end))))
(error nil)))))
;; Filenames and URLs www.com/foo%32bar
(defvar thing-at-point-file-name-chars "-~/[:alnum:]_.${}#%,:"
"Characters allowable in filenames.")
(put 'filename 'end-op
(lambda ()
(re-search-forward (concat "\\=[" thing-at-point-file-name-chars "]*")
nil t)))
(put 'filename 'beginning-op
(lambda ()
(if (re-search-backward (concat "[^" thing-at-point-file-name-chars "]")
nil t)
(forward-char)
(goto-char (point-min)))))
(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.")
(defvar thing-at-point-short-url-regexp
(concat "[-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''.")
(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) .")
(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)))))
(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)))))
;; The normal thingatpt mechanism doesn't work for complex regexps.
;; This should work for almost any regexp wherever we are in the
;; match. To do a perfect job for any arbitrary regexp would mean
;; testing every position before point. Regexp searches won't find
;; matches that straddle the start position so we search forwards once
;; and then back repeatedly and then back up a char at a time.
(defun thing-at-point-looking-at (regexp)
"Return non-nil if point is in or just after a match for REGEXP.
Set the match data from the earliest such match ending at or after
point."
(save-excursion
(let ((old-point (point)) match)
(and (looking-at regexp)
(>= (match-end 0) old-point)
(setq match (point)))
;; Search back repeatedly from end of next match.
;; This may fail if next match ends before this match does.
(re-search-forward regexp nil 'limit)
(while (and (re-search-backward regexp nil t)
(or (> (match-beginning 0) old-point)
(and (looking-at regexp) ; Extend match-end past search start
(>= (match-end 0) old-point)
(setq match (point))))))
(if (not match) nil
(goto-char match)
;; Back up a char at a time in case search skipped
;; intermediate match straddling search start pos.
(while (and (not (bobp))
(progn (backward-char 1) (looking-at regexp))
(>= (match-end 0) old-point)
(setq match (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]+>?"
"A regular expression probably matching an email address.
This does not match the real name portion, only the address, optionally
with angle brackets.")
;; Haven't set 'forward-op on 'email nor defined 'forward-email' because
;; not sure they're actually needed, and URL seems to skip them too.
;; Note that (end-of-thing 'email) and (beginning-of-thing 'email)
;; work automagically, though.
(put 'email 'bounds-of-thing-at-point
(lambda ()
(let ((thing (thing-at-point-looking-at thing-at-point-email-regexp)))
(if thing
(let ((beginning (match-beginning 0))
(end (match-end 0)))
(cons beginning end))))))
(put 'email 'thing-at-point
(lambda ()
(let ((boundary-pair (bounds-of-thing-at-point 'email)))
(if boundary-pair
(buffer-substring-no-properties
(car boundary-pair) (cdr boundary-pair))))))
;; Whitespace
(defun forward-whitespace (arg)
(interactive "p")
(if (natnump arg)
(re-search-forward "[ \t]+\\|\n" nil 'move arg)
(while (< arg 0)
(if (re-search-backward "[ \t]+\\|\n" nil 'move)
(or (eq (char-after (match-beginning 0)) 10)
(skip-chars-backward " \t")))
(setq arg (1+ arg)))))
;; Buffer
(put 'buffer 'end-op (lambda () (goto-char (point-max))))
(put 'buffer 'beginning-op (lambda () (goto-char (point-min))))
;; Symbols
(defun forward-symbol (arg)
(interactive "p")
(if (natnump arg)
(re-search-forward "\\(\\sw\\|\\s_\\)+" nil 'move arg)
(while (< arg 0)
(if (re-search-backward "\\(\\sw\\|\\s_\\)+" nil 'move)
(skip-syntax-backward "w_"))
(setq arg (1+ arg)))))
;; Syntax blocks
(defun forward-same-syntax (&optional arg)
(interactive "p")
(while (< arg 0)
(skip-syntax-backward
(char-to-string (char-syntax (char-before))))
(setq arg (1+ arg)))
(while (> arg 0)
(skip-syntax-forward (char-to-string (char-syntax (char-after))))
(setq arg (1- arg))))
;; Aliases
(defun word-at-point () (thing-at-point 'word))
(defun sentence-at-point () (thing-at-point 'sentence))
(defun read-from-whole-string (str)
"Read a Lisp expression from STR.
Signal an error if the entire string was not used."
(let* ((read-data (read-from-string str))
(more-left
(condition-case nil
;; The call to `ignore' suppresses a compiler warning.
(progn (ignore (read-from-string (substring str (cdr read-data))))
t)
(end-of-file nil))))
(if more-left
(error "Can't read whole string")
(car read-data))))
(defun form-at-point (&optional thing pred)
(let ((sexp (condition-case nil
(read-from-whole-string (thing-at-point (or thing 'sexp)))
(error nil))))
(if (or (not pred) (funcall pred sexp)) sexp)))
;;;###autoload
(defun sexp-at-point ()
"Return the sexp at point, or nil if none is found."
(form-at-point 'sexp))
;;;###autoload
(defun symbol-at-point ()
"Return the symbol at point, or nil if none is found."
(let ((thing (thing-at-point 'symbol)))
(if thing (intern thing))))
;;;###autoload
(defun number-at-point ()
"Return the number at point, or nil if none is found."
(form-at-point 'sexp 'numberp))
;;;###autoload
(defun list-at-point ()
"Return the Lisp list at point, or nil if none is found."
(form-at-point 'list 'listp))
;; arch-tag: bb65a163-dae2-4055-aedc-fe11f497f698
;;; thingatpt.el ends here