xemacs-beta: lisp/format.el comparison

comparison lisp/format.el @ 209:41ff10fd062f r20-4b3

Import from CVS: tag r20-4b3

author	cvs
date	Mon, 13 Aug 2007 10:04:58 +0200
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children	1f0dabaa0855

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+:41ff10fd062f
+;;; format.el --- read and save files in multiple formats
+;; Copyright (c) 1994, 1995, 1997 Free Software Foundation
+;; Author: Boris Goldowsky <boris@gnu.ai.mit.edu>
+;; Keywords: extensions, dumped
+;; This file is part of XEmacs.
+;; XEmacs 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 2, or (at your option)
+;; any later version.
+;; XEmacs 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 XEmacs; see the file COPYING.  If not, write to the Free
+;; Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+;; 02111-1307, USA.
+;;; Synched up with: Emacs/Mule zeta.
+;;; Commentary:
+;; This file is dumped with XEmacs.
+;; This file defines a unified mechanism for saving & loading files stored
+;; in different formats.  `format-alist' contains information that directs
+;; Emacs to call an encoding or decoding function when reading or writing
+;; files that match certain conditions.
+;;
+;; When a file is visited, its format is determined by matching the
+;; beginning of the file against regular expressions stored in
+;; `format-alist'.  If this fails, you can manually translate the buffer
+;; using `format-decode-buffer'.  In either case, the formats used are
+;; listed in the variable `buffer-file-format', and become the default
+;; format for saving the buffer.  To save a buffer in a different format,
+;; change this variable, or use `format-write-file'.
+;;
+;; Auto-save files are normally created in the same format as the visited
+;; file, but the variable `auto-save-file-format' can be set to a
+;; particularly fast or otherwise preferred format to be used for
+;; auto-saving (or nil to do no encoding on auto-save files, but then you
+;; risk losing any text-properties in the buffer).
+;;
+;; You can manually translate a buffer into or out of a particular format
+;; with the functions `format-encode-buffer' and `format-decode-buffer'.
+;; To translate just the region use the functions `format-encode-region'
+;; and `format-decode-region'.
+;;
+;; You can define a new format by writing the encoding and decoding
+;; functions, and adding an entry to `format-alist'.  See enriched.el for
+;; an example of how to implement a file format.  There are various
+;; functions defined in this file that may be useful for writing the
+;; encoding and decoding functions:
+;;  * `format-annotate-region' and `format-deannotate-region' allow a
+;;     single alist of information to be used for encoding and decoding.
+;;     The alist defines a correspondence between strings in the file
+;;     ("annotations") and text-properties in the buffer.
+;;  * `format-replace-strings' is similarly useful for doing simple
+;;     string->string translations in a reversible manner.
+;;; Code:
+(put 'buffer-file-format 'permanent-local t)
+(defvar format-alist
+'((image/jpeg "JPEG image" "\377\330\377\340\000\020JFIF"
+		image-decode-jpeg nil t image-mode)
+(image/gif "GIF image" "GIF8[79]"
+	       image-decode-gif nil t image-mode)
+(image/png "Portable Network Graphics" "\211PNG"
+	       image-decode-png nil t image-mode)
+(image/x-xpm "XPM image" "/\\* XPM \\*/"
+		 image-decode-xpm nil t image-mode)
+(text/enriched "Extended MIME text/enriched format."
+		   "Content-[Tt]ype:[ \t]*text/enriched"
+		   enriched-decode enriched-encode t enriched-mode)
+(text/richtext "Extended MIME obsolete text/richtext format."
+		   "Content-[Tt]ype:[ \t]*text/richtext"
+		   richtext-decode richtext-encode t enriched-mode)
+(plain "Standard ASCII format, no text properties."
+	   ;; Plain only exists so that there is an obvious neutral choice in
+	   ;; the completion list.
+	   nil nil nil nil nil))
+"List of information about understood file formats.
+Elements are of the form \(NAME DOC-STR REGEXP FROM-FN TO-FN MODIFY MODE-FN).
+NAME    is a symbol, which is stored in `buffer-file-format'.
+DOC-STR should be a single line providing more information about the
+format.  It is currently unused, but in the future will be shown to
+the user if they ask for more information.
+REGEXP  is a regular expression to match against the beginning of the file;
+it should match only files in that format.
+FROM-FN is called to decode files in that format; it gets two args, BEGIN
+and END, and can make any modifications it likes, returning the new
+end.  It must make sure that the beginning of the file no longer
+matches REGEXP, or else it will get called again.
+TO-FN   is called to encode a region into that format; it is passed three
+arguments: BEGIN, END, and BUFFER.  BUFFER is the original buffer that
+the data being written came from, which the function could use, for
+example, to find the values of local variables.  TO-FN should either
+return a list of annotations like `write-region-annotate-functions',
+or modify the region and return the new end.
+MODIFY, if non-nil, means the TO-FN wants to modify the region.  If nil,
+TO-FN will not make any changes but will instead return a list of
+annotations.
+MODE-FN, if specified, is called when visiting a file with that format.")
+;;; Basic Functions (called from Lisp)
+(defun format-annotate-function (format from to)
+"Returns annotations for writing region as FORMAT.
+FORMAT is a symbol naming one of the formats defined in `format-alist',
+it must be a single symbol, not a list like `buffer-file-format'.
+FROM and TO delimit the region to be operated on in the current buffer.
+This function works like a function on `write-region-annotate-functions':
+it either returns a list of annotations, or returns with a different buffer
+current, which contains the modified text to write.
+For most purposes, consider using `format-encode-region' instead."
+;; This function is called by write-region (actually build-annotations)
+;; for each element of buffer-file-format.
+(let* ((info (assq format format-alist))
+	 (to-fn  (nth 4 info))
+	 (modify (nth 5 info)))
+(if to-fn
+	(if modify
+	    ;; To-function wants to modify region.  Copy to safe place.
+	    (let ((copy-buf (get-buffer-create " *Format Temp*")))
+	      (copy-to-buffer copy-buf from to)
+	      (set-buffer copy-buf)
+	      (format-insert-annotations write-region-annotations-so-far from)
+	      (funcall to-fn (point-min) (point-max))
+	      nil)
+	  ;; Otherwise just call function, it will return annotations.
+	  (funcall to-fn from to)))))
+(defun format-decode (format length &optional visit-flag)
+;; This function is called by insert-file-contents whenever a file is read.
+"Decode text from any known FORMAT.
+FORMAT is a symbol appearing in `format-alist' or a list of such symbols,
+or nil, in which case this function tries to guess the format of the data by
+matching against the regular expressions in `format-alist'.  After a match is
+found and the region decoded, the alist is searched again from the beginning
+for another match.
+Second arg LENGTH is the number of characters following point to operate on.
+If optional third arg VISIT-FLAG is true, set `buffer-file-format'
+to the list of formats used, and call any mode functions defined for those
+formats.
+Returns the new length of the decoded region.
+For most purposes, consider using `format-decode-region' instead."
+(let ((mod (buffer-modified-p))
+	(begin (point))
+	(end (+ (point) length)))
+(if (null format)
+	;; Figure out which format it is in, remember list in `format'.
+	(let ((try format-alist))
+	  (while try
+	    (let* ((f (car try))
+		   (regexp (nth 2 f))
+		   (p (point)))
+	      (if (and regexp (looking-at regexp)
+		       (< (match-end 0) (+ begin length)))
+		  (progn
+		    (setq format (cons (car f) format))
+		    ;; Decode it
+		    (if (nth 3 f) (setq end (funcall (nth 3 f) begin end)))
+		    ;; Call visit function if required
+		    (if (and visit-flag (nth 6 f)) (funcall (nth 6 f) 1))
+		    ;; Safeguard against either of the functions changing pt.
+		    (goto-char p)
+		    ;; Rewind list to look for another format
+		    (setq try format-alist))
+		(setq try (cdr try))))))
+;; Deal with given format(s)
+(or (listp format) (setq format (list format)))
+(let ((do format) f)
+	(while do
+	  (or (setq f (assq (car do) format-alist))
+	      (error "Unknown format" (car do)))
+	  ;; Decode:
+	  (if (nth 3 f) (setq end (funcall (nth 3 f) begin end)))
+	  ;; Call visit function if required
+	  (if (and visit-flag (nth 6 f)) (funcall (nth 6 f) 1))
+	  (setq do (cdr do)))))
+(if visit-flag
+	(setq buffer-file-format format))
+(set-buffer-modified-p mod)
+;; Return new length of region
+(- end begin)))
+;;;
+;;; Interactive functions & entry points
+;;;
+(defun format-decode-buffer (&optional format)
+"Translate the buffer from some FORMAT.
+If the format is not specified, this function attempts to guess.
+`buffer-file-format' is set to the format used, and any mode-functions
+for the format are called."
+(interactive
+(list (format-read "Translate buffer from format (default: guess): ")))
+(save-excursion
+(goto-char (point-min))
+(format-decode format (buffer-size) t)))
+(defun format-decode-region (from to &optional format)
+"Decode the region from some format.
+Arg FORMAT is optional; if omitted the format will be determined by looking
+for identifying regular expressions at the beginning of the region."
+(interactive
+(list (region-beginning) (region-end)
+	 (format-read "Translate region from format (default: guess): ")))
+(save-excursion
+(goto-char from)
+(format-decode format (- to from) nil)))
+(defun format-encode-buffer (&optional format)
+"Translate the buffer into FORMAT.
+FORMAT defaults to `buffer-file-format'.  It is a symbol naming one of the
+formats defined in `format-alist', or a list of such symbols."
+(interactive
+(list (format-read (format "Translate buffer to format (default %s): "
+			      buffer-file-format))))
+(format-encode-region (point-min) (point-max) format))
+(defun format-encode-region (beg end &optional format)
+"Translate the region into some FORMAT.
+FORMAT defaults to `buffer-file-format', it is a symbol naming
+one of the formats defined in `format-alist', or a list of such symbols."
+(interactive
+(list (region-beginning) (region-end)
+	(format-read (format "Translate region to format (default %s): "
+			     buffer-file-format))))
+(if (null format)    (setq format buffer-file-format))
+(if (symbolp format) (setq format (list format)))
+(save-excursion
+(goto-char end)
+(let ( ; (cur-buf (current-buffer))
+	 (end (point-marker)))
+(while format
+(let* ((info (assq (car format) format-alist))
+	      (to-fn  (nth 4 info))
+	      (modify (nth 5 info))
+	      ;; result
+	      )
+	 (if to-fn
+	     (if modify
+		 (setq end (funcall to-fn beg end (current-buffer)))
+	       (format-insert-annotations
+		(funcall to-fn beg end (current-buffer)))))
+	 (setq format (cdr format)))))))
+(defun format-write-file (filename format)
+"Write current buffer into a FILE using some FORMAT.
+Makes buffer visit that file and sets the format as the default for future
+saves.  If the buffer is already visiting a file, you can specify a directory
+name as FILE, to write a file of the same old name in that directory."
+(interactive
+;; Same interactive spec as write-file, plus format question.
+(let* ((file (if buffer-file-name
+		    (read-file-name "Write file: "
+				    nil nil nil nil)
+		  (read-file-name "Write file: "
+				  (cdr (assq 'default-directory
+					     (buffer-local-variables)))
+				  nil nil (buffer-name))))
+	  (fmt (format-read (format "Write file `%s' in format: "
+				    (file-name-nondirectory file)))))
+(list file fmt)))
+(setq buffer-file-format format)
+(write-file filename))
+(defun format-find-file (filename format)
+"Find the file FILE using data format FORMAT.
+If FORMAT is nil then do not do any format conversion."
+(interactive
+;; Same interactive spec as write-file, plus format question.
+(let* ((file (read-file-name "Find file: "))
+	  (fmt (format-read (format "Read file `%s' in format: "
+				    (file-name-nondirectory file)))))
+(list file fmt)))
+(let ((format-alist nil))
+(find-file filename))
+(if format
+(format-decode-buffer format)))
+(defun format-insert-file (filename format &optional beg end)
+"Insert the contents of file FILE using data format FORMAT.
+If FORMAT is nil then do not do any format conversion.
+The optional third and fourth arguments BEG and END specify
+the part of the file to read.
+The return value is like the value of `insert-file-contents':
+a list (ABSOLUTE-FILE-NAME . SIZE)."
+(interactive
+;; Same interactive spec as write-file, plus format question.
+(let* ((file (read-file-name "Find file: "))
+	  (fmt (format-read (format "Read file `%s' in format: "
+				    (file-name-nondirectory file)))))
+(list file fmt)))
+(let (value size)
+(let ((format-alist nil))
+(setq value (insert-file-contents filename nil beg end))
+(setq size (nth 1 value)))
+(if format
+	(setq size (format-decode format size)
+	      value (cons (car value) size)))
+value))
+(defun format-read (&optional prompt)
+"Read and return the name of a format.
+Return value is a list, like `buffer-file-format'; it may be nil.
+Formats are defined in `format-alist'.  Optional arg is the PROMPT to use."
+(let* ((table (mapcar (lambda (x) (list (symbol-name (car x))))
+			format-alist))
+	 (ans (completing-read (or prompt "Format: ") table nil t)))
+(if (not (equal "" ans)) (list (intern ans)))))
+;;;
+;;; Below are some functions that may be useful in writing encoding and
+;;; decoding functions for use in format-alist.
+;;;
+(defun format-replace-strings (alist &optional reverse beg end)
+"Do multiple replacements on the buffer.
+ALIST is a list of (from . to) pairs, which should be proper arguments to
+`search-forward' and `replace-match' respectively.
+Optional 2nd arg REVERSE, if non-nil, means the pairs are (to . from), so that
+you can use the same list in both directions if it contains only literal
+strings.
+Optional args BEGIN and END specify a region of the buffer to operate on."
+(save-excursion
+(save-restriction
+(or beg (setq beg (point-min)))
+(if end (narrow-to-region (point-min) end))
+(while alist
+	(let ((from (if reverse (cdr (car alist)) (car (car alist))))
+	      (to   (if reverse (car (cdr alist)) (cdr (car alist)))))
+	  (goto-char beg)
+	  (while (search-forward from nil t)
+	    (goto-char (match-beginning 0))
+	    (insert to)
+	    (set-text-properties (- (point) (length to)) (point)
+				 (text-properties-at (point)))
+	    (delete-region (point) (+ (point) (- (match-end 0)
+						 (match-beginning 0)))))
+	  (setq alist (cdr alist)))))))
+;;; Some list-manipulation functions that we need.
+(defun format-delq-cons (cons list)
+"Remove the given CONS from LIST by side effect,
+and return the new LIST.  Since CONS could be the first element
+of LIST, write `\(setq foo \(format-delq-cons element foo))' to be sure of
+changing the value of `foo'."
+(if (eq cons list)
+(cdr list)
+(let ((p list))
+(while (not (eq (cdr p) cons))
+	(if (null p) (error "format-delq-cons: not an element."))
+	(setq p (cdr p)))
+;; Now (cdr p) is the cons to delete
+(setcdr p (cdr cons))
+list)))
+(defun format-make-relatively-unique (a b)
+"Delete common elements of lists A and B, return as pair.
+Compares using `equal'."
+(let* ((acopy (copy-sequence a))
+	 (bcopy (copy-sequence b))
+	 (tail acopy))
+(while tail
+(let ((dup (member (car tail) bcopy))
+	    (next (cdr tail)))
+	(if dup (setq acopy (format-delq-cons tail acopy)
+		      bcopy (format-delq-cons dup  bcopy)))
+	(setq tail next)))
+(cons acopy bcopy)))
+(defun format-common-tail (a b)
+"Given two lists that have a common tail, return it.
+Compares with `equal', and returns the part of A that is equal to the
+equivalent part of B.  If even the last items of the two are not equal,
+returns nil."
+(let ((la (length a))
+	(lb (length b)))
+;; Make sure they are the same length
+(if (> la lb)
+	(setq a (nthcdr (- la lb) a))
+(setq b (nthcdr (- lb la) b))))
+(while (not (equal a b))
+(setq a (cdr a)
+	  b (cdr b)))
+a)
+(defun format-reorder (items order)
+"Arrange ITEMS to following partial ORDER.
+Elements of ITEMS equal to elements of ORDER will be rearranged to follow the
+ORDER.  Unmatched items will go last."
+(if order
+(let ((item (member (car order) items)))
+	(if item
+	    (cons (car item)
+		  (format-reorder (format-delq-cons item items)
+			   (cdr order)))
+	  (format-reorder items (cdr order))))
+items))
+(put 'face 'format-list-valued t)	; These text-properties take values
+(put 'unknown 'format-list-valued t)	; that are lists, the elements of which
+					; should be considered separately.
+					; See format-deannotate-region and
+					; format-annotate-region.
+;;;
+;;; Decoding
+;;;
+(defun format-deannotate-region (from to translations next-fn)
+"Translate annotations in the region into text properties.
+This sets text properties between FROM to TO as directed by the
+TRANSLATIONS and NEXT-FN arguments.
+NEXT-FN is a function that searches forward from point for an annotation.
+It should return a list of 4 elements: \(BEGIN END NAME POSITIVE).  BEGIN and
+END are buffer positions bounding the annotation, NAME is the name searched
+for in TRANSLATIONS, and POSITIVE should be non-nil if this annotation marks
+the beginning of a region with some property, or nil if it ends the region.
+NEXT-FN should return nil if there are no annotations after point.
+The basic format of the TRANSLATIONS argument is described in the
+documentation for the `format-annotate-region' function.  There are some
+additional things to keep in mind for decoding, though:
+When an annotation is found, the TRANSLATIONS list is searched for a
+text-property name and value that corresponds to that annotation.  If the
+text-property has several annotations associated with it, it will be used only
+if the other annotations are also in effect at that point.  The first match
+found whose annotations are all present is used.
+The text property thus determined is set to the value over the region between
+the opening and closing annotations.  However, if the text-property name has a
+non-nil `format-list-valued' property, then the value will be consed onto the
+surrounding value of the property, rather than replacing that value.
+There are some special symbols that can be used in the \"property\" slot of
+the TRANSLATIONS list: PARAMETER and FUNCTION \(spelled in uppercase).
+Annotations listed under the pseudo-property PARAMETER are considered to be
+arguments of the immediately surrounding annotation; the text between the
+opening and closing parameter annotations is deleted from the buffer but saved
+as a string.  The surrounding annotation should be listed under the
+pseudo-property FUNCTION.  Instead of inserting a text-property for this
+annotation, the function listed in the VALUE slot is called to make whatever
+changes are appropriate.  The function's first two arguments are the START and
+END locations, and the rest of the arguments are any PARAMETERs found in that
+region.
+Any annotations that are found by NEXT-FN but not defined by TRANSLATIONS
+are saved as values of the `unknown' text-property \(which is list-valued).
+The TRANSLATIONS list should usually contain an entry of the form
+\(unknown \(nil format-annotate-value))
+to write these unknown annotations back into the file."
+(save-excursion
+(save-restriction
+(narrow-to-region (point-min) to)
+(goto-char from)
+(let (next open-ans todo
+		 ;; loc
+		 unknown-ans)
+	(while (setq next (funcall next-fn))
+	  (let* ((loc      (nth 0 next))
+		 (end      (nth 1 next))
+		 (name     (nth 2 next))
+		 (positive (nth 3 next))
+		 (found    nil))
+	    ;; Delete the annotation
+	    (delete-region loc end)
+	    (if positive
+		;; Positive annotations are stacked, remembering location
+		(setq open-ans (cons (list name loc) open-ans))
+	      ;; It is a negative annotation:
+	      ;; Close the top annotation & add its text property.
+	      ;; If the file's nesting is messed up, the close might not match
+	      ;; the top thing on the open-annotations stack.
+	      ;; If no matching annotation is open, just ignore the close.
+	      (if (not (assoc name open-ans))
+		  (message "Extra closing annotation (%s) in file" name)
+	      ;; If one is open, but not on the top of the stack, close
+	      ;; the things in between as well.  Set `found' when the real
+	      ;; one is closed.
+		(while (not found)
+		  (let* ((top (car open-ans)) ; first on stack: should match.
+			 (top-name (car top))
+			 (start (car (cdr top))) ; location of start
+			 (params (cdr (cdr top))) ; parameters
+			 (aalist translations)
+			 (matched nil))
+		    (if (equal name top-name)
+			(setq found t)
+		      (message "Improper nesting in file."))
+		    ;; Look through property names in TRANSLATIONS
+		    (while aalist
+		      (let ((prop (car (car aalist)))
+			    (alist (cdr (car aalist))))
+			;; And look through values for each property
+			(while alist
+			  (let ((value (car (car alist)))
+				(ans (cdr (car alist))))
+			    (if (member top-name ans)
+				;; This annotation is listed, but still have to
+				;; check if multiple annotations are satisfied
+				(if (member 'nil (mapcar
+						  (lambda (r)
+						    (assoc r open-ans))
+						  ans))
+				    nil	; multiple ans not satisfied
+				  ;; Yes, all set.
+				  ;; If there are multiple annotations going
+				  ;; into one text property, adjust the
+				  ;; begin points of the other annotations
+				  ;; so that we don't get double marking.
+				  (let ((to-reset ans)
+					this-one)
+				    (while to-reset
+				      (setq this-one
+					    (assoc (car to-reset)
+						   (cdr open-ans)))
+				      (if this-one
+					  (setcar (cdr this-one) loc))
+				      (setq to-reset (cdr to-reset))))
+				  ;; Set loop variables to nil so loop
+				  ;; will exit.
+				  (setq alist nil aalist nil matched t
+					;; pop annotation off stack.
+					open-ans (cdr open-ans))
+				  (cond
+				   ;; Check for pseudo-properties
+				   ((eq prop 'PARAMETER)
+				    ;; This is a parameter of the top open ann:
+				    ;; delete text and use as arg.
+				    (if open-ans
+					;; (If nothing open, discard).
+					(setq open-ans
+					      (cons (append (car open-ans)
+							    (list
+							     (buffer-substring
+							      start loc)))
+						    (cdr open-ans))))
+				    (delete-region start loc))
+				   ((eq prop 'FUNCTION)
+				    ;; Not a property, but a function to call.
+				    (let ((rtn (apply value start loc params)))
+				      (if rtn (setq todo (cons rtn todo)))))
+				   (t
+				    ;; Normal property/value pair
+				    (setq todo
+					  (cons (list start loc prop value)
+						todo)))))))
+			  (setq alist (cdr alist))))
+		      (setq aalist (cdr aalist)))
+		    (if matched
+			nil
+		      ;; Didn't find any match for the annotation:
+		      ;; Store as value of text-property `unknown'.
+		      (setq open-ans (cdr open-ans))
+		      (setq todo (cons (list start loc 'unknown top-name)
+				       todo))
+		      (setq unknown-ans (cons name unknown-ans)))))))))
+	;; Once entire file has been scanned, add the properties.
+	(while todo
+	  (let* ((item (car todo))
+		 (from (nth 0 item))
+		 (to   (nth 1 item))
+		 (prop (nth 2 item))
+		 (val  (nth 3 item)))
+	    (put-text-property
+	       from to prop
+	       (cond ((numberp val) ; add to ambient value if numeric
+		      (+ val (or (get-text-property from prop) 0)))
+		     ((get prop 'format-list-valued) ; value gets consed onto
+						     ; list-valued properties
+		      (let ((prev (get-text-property from prop)))
+			(cons val (if (listp prev) prev (list prev)))))
+		     (t val)))) ; normally, just set to val.
+	  (setq todo (cdr todo)))
+	(if unknown-ans
+	    (message "Unknown annotations: %s" unknown-ans))))))
+;;;
+;;; Encoding
+;;;
+(defun format-insert-annotations (list &optional offset)
+"Apply list of annotations to buffer as `write-region' would.
+Inserts each element of the given LIST of buffer annotations at its
+appropriate place.  Use second arg OFFSET if the annotations' locations are
+not relative to the beginning of the buffer: annotations will be inserted
+at their location-OFFSET+1 \(ie, the offset is treated as the character number
+of the first character in the buffer)."
+(if (not offset)
+(setq offset 0)
+(setq offset (1- offset)))
+(let ((l (reverse list)))
+(while l
+(goto-char (- (car (car l)) offset))
+(insert (cdr (car l)))
+(setq l (cdr l)))))
+(defun format-annotate-value (old new)
+"Return OLD and NEW as a \(close . open) annotation pair.
+Useful as a default function for TRANSLATIONS alist when the value of the text
+property is the name of the annotation that you want to use, as it is for the
+`unknown' text property."
+(cons (if old (list old))
+	(if new (list new))))
+(defun format-annotate-region (from to trans format-fn ignore)
+"Generate annotations for text properties in the region.
+Searches for changes between FROM and TO, and describes them with a list of
+annotations as defined by alist TRANSLATIONS and FORMAT-FN.  IGNORE lists text
+properties not to consider; any text properties that are neither ignored nor
+listed in TRANSLATIONS are warned about.
+If you actually want to modify the region, give the return value of this
+function to `format-insert-annotations'.
+Format of the TRANSLATIONS argument:
+Each element is a list whose car is a PROPERTY, and the following
+elements are VALUES of that property followed by the names of zero or more
+ANNOTATIONS.  Whenever the property takes on that value, the annotations
+\(as formatted by FORMAT-FN) are inserted into the file.
+When the property stops having that value, the matching negated annotation
+will be inserted \(it may actually be closed earlier and reopened, if
+necessary, to keep proper nesting).
+If the property's value is a list, then each element of the list is dealt with
+separately.
+If a VALUE is numeric, then it is assumed that there is a single annotation
+and each occurrence of it increments the value of the property by that number.
+Thus, given the entry \(left-margin \(4 \"indent\")), if the left margin
+changes from 4 to 12, two <indent> annotations will be generated.
+If the VALUE is nil, then instead of annotations, a function should be
+specified.  This function is used as a default: it is called for all
+transitions not explicitly listed in the table.  The function is called with
+two arguments, the OLD and NEW values of the property.  It should return
+lists of annotations like `format-annotate-location' does.
+The same structure can be used in reverse for reading files."
+(let ((all-ans nil)    ; All annotations - becomes return value
+	(open-ans nil)   ; Annotations not yet closed
+	(loc nil)	 ; Current location
+	(not-found nil)) ; Properties that couldn't be saved
+(while (or (null loc)
+	       (and (setq loc (next-property-change loc nil to))
+		    (< loc to)))
+(or loc (setq loc from))
+(let* ((ans (format-annotate-location loc (= loc from) ignore trans))
+	     (neg-ans (format-reorder (aref ans 0) open-ans))
+	     (pos-ans (aref ans 1))
+	     (ignored (aref ans 2)))
+	(setq not-found (append ignored not-found)
+	      ignore    (append ignored ignore))
+	;; First do the negative (closing) annotations
+	(while neg-ans
+	  ;; Check if it's missing.  This can happen (eg, a numeric property
+	  ;; going negative can generate closing annotations before there are
+	  ;; any open).  Warn user & ignore.
+	  (if (not (member (car neg-ans) open-ans))
+	      (message "Can't close %s: not open." (car neg-ans))
+	    (while (not (equal (car neg-ans) (car open-ans)))
+	      ;; To close anno. N, need to first close ans 1 to N-1,
+	      ;; remembering to re-open them later.
+	      (setq pos-ans (cons (car open-ans) pos-ans))
+	      (setq all-ans
+		    (cons (cons loc (funcall format-fn (car open-ans) nil))
+			  all-ans))
+	      (setq open-ans (cdr open-ans)))
+	    ;; Now remove the one we're really interested in from open list.
+	    (setq open-ans (cdr open-ans))
+	    ;; And put the closing annotation here.
+	    (setq all-ans
+		  (cons (cons loc (funcall format-fn (car neg-ans) nil))
+			all-ans)))
+	  (setq neg-ans (cdr neg-ans)))
+	;; Now deal with positive (opening) annotations
+	(let ( ; (p pos-ans)
+	      )
+	  (while pos-ans
+	    (setq open-ans (cons (car pos-ans) open-ans))
+	    (setq all-ans
+		  (cons (cons loc (funcall format-fn (car pos-ans) t))
+			all-ans))
+	    (setq pos-ans (cdr pos-ans))))))
+;; Close any annotations still open
+(while open-ans
+(setq all-ans
+	    (cons (cons to (funcall format-fn (car open-ans) nil))
+		  all-ans))
+(setq open-ans (cdr open-ans)))
+(if not-found
+	(message "These text properties could not be saved:\n    %s"
+		 not-found))
+(nreverse all-ans)))
+;;; Internal functions for format-annotate-region.
+(defun format-annotate-location (loc all ignore trans)
+"Return annotation(s) needed at LOCATION.
+This includes any properties that change between LOC-1 and LOC.
+If ALL is true, don't look at previous location, but generate annotations for
+all non-nil properties.
+Third argument IGNORE is a list of text-properties not to consider.
+Return value is a vector of 3 elements:
+1. List of names of the annotations to close
+2. List of the names of annotations to open.
+3. List of properties that were ignored or couldn't be annotated."
+(let* ((prev-loc (1- loc))
+	 (before-plist (if all nil (text-properties-at prev-loc)))
+	 (after-plist (text-properties-at loc))
+	 p negatives positives prop props not-found)
+;; make list of all property names involved
+(setq p before-plist)
+(while p
+(if (not (memq (car p) props))
+	  (setq props (cons (car p) props)))
+(setq p (cdr (cdr p))))
+(setq p after-plist)
+(while p
+(if (not (memq (car p) props))
+	  (setq props (cons (car p) props)))
+(setq p (cdr (cdr p))))
+(while props
+(setq prop (car props)
+	    props (cdr props))
+(if (memq prop ignore)
+	  nil  ; If it's been ignored before, ignore it now.
+	(let ((before (if all nil (car (cdr (memq prop before-plist)))))
+	      (after (car (cdr (memq prop after-plist)))))
+	  (if (equal before after)
+	      nil ; no change; ignore
+	    (let ((result (format-annotate-single-property-change
+			   prop before after trans)))
+	      (if (not result)
+		  (setq not-found (cons prop not-found))
+		(setq negatives (nconc negatives (car result))
+		      positives (nconc positives (cdr result)))))))))
+(vector negatives positives not-found)))
+(defun format-annotate-single-property-change (prop old new trans)
+"Return annotations for PROPERTY changing from OLD to NEW.
+These are searched for in the TRANSLATIONS alist.
+If NEW does not appear in the list, but there is a default function, then that
+function is called.
+Annotations to open and to close are returned as a dotted pair."
+(let ((prop-alist (cdr (assoc prop trans)))
+	;; default
+	)
+(if (not prop-alist)
+	nil
+;; If property is numeric, nil means 0
+(cond ((and (numberp old) (null new))
+	     (setq new 0))
+	    ((and (numberp new) (null old))
+	     (setq old 0)))
+;; If either old or new is a list, have to treat both that way.
+(if (or (consp old) (consp new))
+	  (let* ((old (if (listp old) old (list old)))
+		 (new (if (listp new) new (list new)))
+		 ;; (tail (format-common-tail old new))
+		 close open)
+	    (while old
+	      (setq close
+		    (append (car (format-annotate-atomic-property-change
+				  prop-alist (car old) nil))
+			    close)
+		    old (cdr old)))
+	    (while new
+	      (setq open
+		    (append (cdr (format-annotate-atomic-property-change
+				  prop-alist nil (car new)))
+			    open)
+		    new (cdr new)))
+	    (format-make-relatively-unique close open))
+	(format-annotate-atomic-property-change prop-alist old new)))))
+(defun format-annotate-atomic-property-change (prop-alist old new)
+"Internal function annotate a single property change.
+PROP-ALIST is the relevant segment of a TRANSLATIONS list.
+OLD and NEW are the values."
+(cond
+;; Numerical annotation - use difference
+((and (numberp old) (numberp new))
+(let* ((entry (progn
+		    (while (and (car (car prop-alist))
+				(not (numberp (car (car prop-alist)))))
+		      (setq prop-alist (cdr prop-alist)))
+		    (car prop-alist)))
+	   (increment (car (car prop-alist)))
+	   (n (ceiling (/ (float (- new old)) (float increment))))
+	   (anno (car (cdr (car prop-alist)))))
+(if (> n 0)
+	  (cons nil (make-list n anno))
+	(cons (make-list (- n) anno) nil))))
+;; Standard annotation
+(t (let ((close (and old (cdr (assoc old prop-alist))))
+	    (open  (and new (cdr (assoc new prop-alist)))))
+	(if (or close open)
+	    (format-make-relatively-unique close open)
+	  ;; Call "Default" function, if any
+	  (let ((default (assq nil prop-alist)))
+	    (if default
+		(funcall (car (cdr default)) old new))))))))
+;;; format.el ends here

Mercurial > hg > xemacs-beta

comparison lisp/format.el @ 209:41ff10fd062f r20-4b3