diff options
author | Gerd Moellmann <gerd@gnu.org> | 2000-07-19 15:52:13 +0000 |
---|---|---|
committer | Gerd Moellmann <gerd@gnu.org> | 2000-07-19 15:52:13 +0000 |
commit | 5953e4d63af5ab87ac22fe2387d8c222fa1db007 (patch) | |
tree | 40a6c77639d5d87b2c6df7aba33b5496ac02861d /lisp/xml.el | |
parent | 29bf0ccb34fe70dec5af6352dcb4482c9bddc2dc (diff) | |
download | emacs-5953e4d63af5ab87ac22fe2387d8c222fa1db007.tar.gz |
*** empty log message ***
Diffstat (limited to 'lisp/xml.el')
-rw-r--r-- | lisp/xml.el | 508 |
1 files changed, 508 insertions, 0 deletions
diff --git a/lisp/xml.el b/lisp/xml.el new file mode 100644 index 00000000000..11b731634a0 --- /dev/null +++ b/lisp/xml.el @@ -0,0 +1,508 @@ +;; @(#) xml.el --- XML parser + +;; Copyright (C) 2000 Free Software Foundation, Inc. + +;; Author: Emmanuel Briot <briot@gnat.com> +;; Maintainer: Emmanuel Briot <briot@gnat.com> +;; Keywords: xml + +;; 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 2, 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; see the file COPYING. If not, write to the +;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, +;; Boston, MA 02111-1307, USA. + +;;; Commentary: + +;; This file contains a full XML parser. It parses a file, and returns a list +;; that can be used internally by any other lisp file. +;; See some example in todo.el + +;;; FILE FORMAT + +;; It does not parse the DTD, if present in the XML file, but knows how to +;; ignore it. The XML file is assumed to be well-formed. In case of error, the +;; parsing stops and the XML file is shown where the parsing stopped. +;; +;; It also knows how to ignore comments, as well as the special ?xml? tag +;; in the XML file. +;; +;; The XML file should have the following format: +;; <node1 attr1="name1" attr2="name2" ...> value +;; <node2 attr3="name3" attr4="name4"> value2 </node2> +;; <node3 attr5="name5" attr6="name6"> value3 </node3> +;; </node1> +;; Of course, the name of the nodes and attributes can be anything. There can +;; be any number of attributes (or none), as well as any number of children +;; below the nodes. +;; +;; There can be only top level node, but with any number of children below. + +;;; LIST FORMAT + +;; The functions `xml-parse-file' and `xml-parse-tag' return a list with +;; the following format: +;; +;; xml-list ::= (node node ...) +;; node ::= (tag_name attribute-list . child_node_list) +;; child_node_list ::= child_node child_node ... +;; child_node ::= node | string +;; tag_name ::= string +;; attribute_list ::= (("attribute" . "value") ("attribute" . "value") ...) +;; | nil +;; string ::= "..." +;; +;; Since XML is case insensitive, tag_name is always converted to lower-cases. +;; tag_name is then converted to a symbol (this is not a string, so that the +;; list takes less space in memory and is faster to traverse). +;; +;; Some macros are provided to ease the parsing of this list + +;;; Code: + +;;******************************************************************* +;;** +;;** Macros to parse the list +;;** +;;******************************************************************* + +(defmacro xml-node-name (node) + "Return the tag associated with NODE. +The tag is a lower-case symbol." + (list 'car node)) + +(defmacro xml-node-attributes (node) + "Return the list of attributes of NODE. +The list can be nil." + (list 'nth 1 node)) + +(defmacro xml-node-children (node) + "Return the list of children of NODE. +This is a list of nodes, and it can be nil." + (list 'cddr node)) + +(defun xml-get-children (node child-name) + "Return the children of NODE whose tag is CHILD-NAME. +CHILD-NAME should be a lower case symbol." + (let ((children (xml-node-children node)) + match) + (while children + (if (car children) + (if (equal (xml-node-name (car children)) child-name) + (set 'match (append match (list (car children)))))) + (set 'children (cdr children))) + match)) + +(defun xml-get-attribute (node attribute) + "Get from NODE the value of ATTRIBUTE. +An empty string is returned if the attribute was not found." + (if (xml-node-attributes node) + (let ((value (assoc attribute (xml-node-attributes node)))) + (if value + (cdr value) + "")) + "")) + +;;******************************************************************* +;;** +;;** Creating the list +;;** +;;******************************************************************* + +(defun xml-parse-file (file &optional parse-dtd) + "Parse the well-formed XML FILE. +Returns the top node with all its children. +If PARSE-DTD is non-nil, the DTD is parsed rather than skipped." + (find-file file) + (let ((xml (xml-parse-region (point-min) + (point-max) + (current-buffer) + parse-dtd))) + (kill-buffer (current-buffer)) + xml)) + +(defun xml-parse-region (beg end &optional buffer parse-dtd) + "Parse the region from BEG to END in BUFFER. +If BUFFER is nil, it defaults to the current buffer. +Returns the XML list for the region, or raises an error if the region +is not a well-formed XML file. +If PARSE-DTD is non-nil, the DTD is parsed rather than skipped, +and returned as the first element of the list" + (let (xml result dtd) + (save-excursion + (if buffer + (set-buffer buffer)) + (goto-char beg) + (while (< (point) end) + (if (search-forward "<" end t) + (progn + (forward-char -1) + (if (null xml) + (progn + (set 'result (xml-parse-tag end parse-dtd)) + (cond + ((listp (car result)) + (set 'dtd (car result)) + (add-to-list 'xml (cdr result))) + (t + (add-to-list 'xml result)))) + + ;; translation of rule [1] of XML specifications + (error "XML files can have only one toplevel tag."))) + (goto-char end))) + (if parse-dtd + (cons dtd (reverse xml)) + (reverse xml))))) + + +(defun xml-parse-tag (end &optional parse-dtd) + "Parse the tag that is just in front of point. +The end tag must be found before the position END in the current buffer. +If PARSE-DTD is non-nil, the DTD of the document, if any, is parsed and +returned as the first element in the list. +Returns one of: + - a list : the matching node + - nil : the point is not looking at a tag. + - a cons cell: the first element is the DTD, the second is the node" + (cond + ;; Processing instructions (like the <?xml version="1.0"?> tag at the + ;; beginning of a document) + ((looking-at "<\\?") + (search-forward "?>" end) + (skip-chars-forward " \t\n") + (xml-parse-tag end)) + ;; Character data (CDATA) sections, in which no tag should be interpreted + ((looking-at "<!\\[CDATA\\[") + (let ((pos (match-end 0))) + (unless (search-forward "]]>" end t) + (error "CDATA section does not end anywhere in the document")) + (buffer-substring-no-properties pos (match-beginning 0)))) + ;; DTD for the document + ((looking-at "<!DOCTYPE") + (let (dtd) + (if parse-dtd + (set 'dtd (xml-parse-dtd end)) + (xml-skip-dtd end)) + (skip-chars-forward " \t\n") + (if dtd + (cons dtd (xml-parse-tag end)) + (xml-parse-tag end)))) + ;; skip comments + ((looking-at "<!--") + (search-forward "-->" end) + (skip-chars-forward " \t\n") + (xml-parse-tag end)) + ;; end tag + ((looking-at "</") + '()) + ;; opening tag + ((looking-at "<\\([^/> \t]+\\)") + (let* ((node-name (match-string 1)) + (children (list (intern (downcase node-name)))) + pos) + (goto-char (match-end 1)) + + ;; parses the attribute list + (set 'children (append children (list (xml-parse-attlist end)))) + + ;; is this an empty element ? + (if (looking-at "/>") + (progn + (forward-char 2) + (skip-chars-forward " \t\n") + (append children '(""))) + + ;; is this a valid start tag ? + (if (= (char-after) ?>) + (progn + (forward-char 1) + (skip-chars-forward " \t\n") + (while (not (looking-at (concat "</" node-name ">"))) + (cond + ((looking-at "</") + (error (concat + "XML: invalid syntax -- invalid end tag (expecting " + node-name + ")"))) + ((= (char-after) ?<) + (set 'children (append children (list (xml-parse-tag end))))) + (t + (set 'pos (point)) + (search-forward "<" end) + (forward-char -1) + (let ((string (buffer-substring-no-properties pos (point))) + (pos 0)) + + ;; Clean up the string (no newline characters) + ;; Not done, since as per XML specifications, the XML processor + ;; should always pass the whole string to the application. + ;; (while (string-match "\\s +" string pos) + ;; (set 'string (replace-match " " t t string)) + ;; (set 'pos (1+ (match-beginning 0)))) + + (set 'children (append children + (list (xml-substitute-special string)))))))) + (goto-char (match-end 0)) + (skip-chars-forward " \t\n") + (if (> (point) end) + (error "XML: End tag for %s not found before end of region." + node-name)) + children + ) + + ;; This was an invalid start tag + (error "XML: Invalid attribute list") + )))) + )) + +(defun xml-parse-attlist (end) + "Return the attribute-list that point is looking at. +The search for attributes end at the position END in the current buffer. +Leaves the point on the first non-blank character after the tag." + (let ((attlist '()) + name) + (skip-chars-forward " \t\n") + (while (looking-at "\\([a-zA-Z_:][a-zA-Z0-9.-_:]*\\)[ \t\n]*=[ \t\n]*") + (set 'name (intern (downcase (match-string 1)))) + (goto-char (match-end 0)) + + ;; Do we have a string between quotes (or double-quotes), + ;; or a simple word ? + (unless (looking-at "\"\\([^\"]+\\)\"") + (unless (looking-at "'\\([^\"]+\\)'") + (error "XML: Attribute values must be given between quotes."))) + + ;; Each attribute must be unique within a given element + (if (assoc name attlist) + (error "XML: each attribute must be unique within an element.")) + + (set 'attlist (append attlist + (list (cons name (match-string 1))))) + (goto-char (match-end 0)) + (skip-chars-forward " \t\n") + (if (> (point) end) + (error "XML: end of attribute list not found before end of region.")) + ) + attlist + )) + +;;******************************************************************* +;;** +;;** The DTD (document type declaration) +;;** The following functions know how to skip or parse the DTD of +;;** a document +;;** +;;******************************************************************* + +(defun xml-skip-dtd (end) + "Skip the DTD that point is looking at. +The DTD must end before the position END in the current buffer. +The point must be just before the starting tag of the DTD. +This follows the rule [28] in the XML specifications." + (forward-char (length "<!DOCTYPE")) + (if (looking-at "[ \t\n]*>") + (error "XML: invalid DTD (excepting name of the document)")) + (condition-case nil + (progn + (forward-word 1) ;; name of the document + (skip-chars-forward " \t\n") + (if (looking-at "\\[") + (re-search-forward "\\][ \t\n]*>" end) + (search-forward ">" end))) + (error (error "XML: No end to the DTD")))) + +(defun xml-parse-dtd (end) + "Parse the DTD that point is looking at. +The DTD must end before the position END in the current buffer." + (let (dtd type element end-pos) + (forward-char (length "<!DOCTYPE")) + (skip-chars-forward " \t\n") + (if (looking-at ">") + (error "XML: invalid DTD (excepting name of the document)")) + + ;; Get the name of the document + (looking-at "\\sw+") + (set 'dtd (list 'dtd (match-string-no-properties 0))) + (goto-char (match-end 0)) + + (skip-chars-forward " \t\n") + + ;; External DTDs => don't know how to handle them yet + (if (looking-at "SYSTEM") + (error "XML: Don't know how to handle external DTDs.")) + + (if (not (= (char-after) ?\[)) + (error "XML: Unknown declaration in the DTD.")) + + ;; Parse the rest of the DTD + (forward-char 1) + (while (and (not (looking-at "[ \t\n]*\\]")) + (<= (point) end)) + (cond + + ;; Translation of rule [45] of XML specifications + ((looking-at + "[\t \n]*<!ELEMENT[ \t\n]+\\([a-zA-Z0-9.%;]+\\)[ \t\n]+\\([^>]+\\)>") + + (setq element (intern (downcase (match-string-no-properties 1))) + type (match-string-no-properties 2)) + (set 'end-pos (match-end 0)) + + ;; Translation of rule [46] of XML specifications + (cond + ((string-match "^EMPTY[ \t\n]*$" type) ;; empty declaration + (set 'type 'empty)) + ((string-match "^ANY[ \t\n]*$" type) ;; any type of contents + (set 'type 'any)) + ((string-match "^(\\(.*\\))[ \t\n]*$" type) ;; children ([47]) + (set 'type (xml-parse-elem-type (match-string-no-properties 1 type)))) + ((string-match "^%[^;]+;[ \t\n]*$" type) ;; substitution + nil) + (t + (error "XML: Invalid element type in the DTD"))) + + ;; rule [45]: the element declaration must be unique + (if (assoc element dtd) + (error "XML: elements declaration must be unique in a DTD (<%s>)." + (symbol-name element))) + + ;; Store the element in the DTD + (set 'dtd (append dtd (list (list element type)))) + (goto-char end-pos) + ) + + + (t + (error "XML: Invalid DTD item")) + ) + ) + + ;; Skip the end of the DTD + (search-forward ">" end) + dtd + )) + + +(defun xml-parse-elem-type (string) + "Convert a STRING for an element type into an elisp structure." + + (let (elem modifier) + (if (string-match "(\\([^)]+\\))\\([+*?]?\\)" string) + (progn + (setq elem (match-string 1 string) + modifier (match-string 2 string)) + (if (string-match "|" elem) + (set 'elem (append '(choice) + (mapcar 'xml-parse-elem-type + (split-string elem "|")))) + (if (string-match "," elem) + (set 'elem (append '(seq) + (mapcar 'xml-parse-elem-type + (split-string elem ",")))) + ))) + (if (string-match "[ \t\n]*\\([^+*?]+\\)\\([+*?]?\\)" string) + (setq elem (match-string 1 string) + modifier (match-string 2 string)))) + + (if (and (stringp elem) + (string= elem "#PCDATA")) + (set 'elem 'pcdata)) + + (cond + ((string= modifier "+") + (list '+ elem)) + ((string= modifier "*") + (list '* elem)) + ((string= modifier "?") + (list '? elem)) + (t + elem)))) + + +;;******************************************************************* +;;** +;;** Substituting special XML sequences +;;** +;;******************************************************************* + +(defun xml-substitute-special (string) + "Return STRING, after subsituting special XML sequences." + (while (string-match "&" string) + (set 'string (replace-match "&" t nil string))) + (while (string-match "<" string) + (set 'string (replace-match "<" t nil string))) + (while (string-match ">" string) + (set 'string (replace-match ">" t nil string))) + (while (string-match "'" string) + (set 'string (replace-match "'" t nil string))) + (while (string-match """ string) + (set 'string (replace-match "\"" t nil string))) + string) + +;;******************************************************************* +;;** +;;** Printing a tree. +;;** This function is intended mainly for debugging purposes. +;;** +;;******************************************************************* + +(defun xml-debug-print (xml) + (while xml + (xml-debug-print-internal (car xml) "") + (set 'xml (cdr xml))) + ) + +(defun xml-debug-print-internal (xml &optional indent-string) + "Outputs the XML tree in the current buffer. +The first line indented with INDENT-STRING." + (let ((tree xml) + attlist) + (unless indent-string + (set 'indent-string "")) + + (insert indent-string "<" (symbol-name (xml-node-name tree))) + + ;; output the attribute list + (set 'attlist (xml-node-attributes tree)) + (while attlist + (insert " ") + (insert (symbol-name (caar attlist)) "=\"" (cdar attlist) "\"") + (set 'attlist (cdr attlist))) + + (insert ">") + + (set 'tree (xml-node-children tree)) + + ;; output the children + (while tree + (cond + ((listp (car tree)) + (insert "\n") + (xml-debug-print-internal (car tree) (concat indent-string " ")) + ) + ((stringp (car tree)) + (insert (car tree)) + ) + (t + (error "Invalid XML tree"))) + (set 'tree (cdr tree)) + ) + + (insert "\n" indent-string + "</" (symbol-name (xml-node-name xml)) ">") + )) + +(provide 'xml) + +;;; xml.el ends here |