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iso-2022 HTML -> XML

From: Tomohisa Yazaki <yazaki@doi.cs.keio.ac.jp>
Date: Thu, 02 Sep 1999 20:24:44 +0900
Message-Id: <199909021124.UAA00318@chitose.doi.ics.keio.ac.jp>
To: html-tidy@w3.org
I came across some problems when I tried to use Java port of
Tidy(version 26th July 1999) in order to translate japanese HTML
documents to XML documents and parse them using IBM's XML4J(SAX and
DOM parser).

  (1) JTidy allows an XML document to have comments which include
 "--". In XML documents, `the string "--" (double-hyphen) must not occur
 within comments', while in HTML documents `authors should avoid putting
 two or more adjacent hyphens inside comments'.

  (2) Attribute values defined in lower case in DTD are not folded to
 lower case. For example,
        <IMG SRC = image.gif ALT = MYGIF ALIGN=BOTTOM >
 is mapped to 
        <img src="image.gif" alt="MYGIF" align="BOTTOM" />.
 It should be mapped to
        <img src="image.gif" alt="MYGIF" align="bottom" />

  (3) An XML declaration does not have an encoding declaration even if
 Tidy's character encoding option(-iso2022, -latin1 ...) is specified.
 Consequently, XML processors assume that the document is encoded in
 UTF-8 and complain that the document includes invalid characters.

I have made a patch to fix these problems.

For the first problem, I added cleanComment() method to
Clean.java. This method accepts a Node object and removes all comment
nodes which include "--". To make this patch work, I fixed a bug that
doctype.next.prev is not set in setXHTMLDocType() and fixDocType() in
Lexer.java. Removing the whole comment is a rough way, replacing "--"
to something else may be a better way.

For the second problem, the patched code get corresponding Attribute
object from AttributeTable.attrs and check if its attrchk field is not
null. When it is not null, attribute value is folded to lower
case. Attribute values which are not supported in AttrCheckImpl.java
are not corrected.

For the third problem, I added some lines to fixXMLPI() to append an
encoding declaration according to configuration.CharEncoding . I don't
know what encoding name is suitable when configuration.CharEnconding
is RAW. Currently "ANSI_X3.4-1968"(ASCII) is assigned. When
configuration.CharEncoding is ISO2022, "ISO-2022-JP" is appended. To
treat ISO-2022 encoding family properly, language-specific encoding
name of ISO-2022 family(ISO-2022-KR, ISO-2022-CN...) should be
appended. This encoding name could be determined by a user option or
auto-identifying character encoding. I'm not familiar with
auto-identifying ISO-2022 character encoding, but I guess counting
escape sequences is likely to be a solution. Unfortunately, plain
"ISO-2022" is not included in IANA's character sets list[1], which is
referred by XML specification, therefore XML processors might tend to
reject plain "ISO-2022" as encoding name.(In fact, IBM's XML4J doesn't
accept "ISO-2022", though it accepts "ISO-2022-JP")

I'm not sure this patch does not harm original JTidy's function, but
it seems to be working properly for my own purpose.


By the way, after applying this patch to JTidy, the XML processor
still complains as follows.

[Warning] transitional.dtd:340:51: Warning: attribute "xml:space" is
recommended to be declared as "xml:space (default|preserve) #IMPLIED".
[Warning] transitional.dtd:351:51: Warning: attribute "xml:space" is
recommended to be declared as "xml:space (default|preserve) #IMPLIED".
[Warning] transitional.dtd:570:49: Warning: attribute "xml:space" is
recommended to be declared as "xml:space (default|preserve) #IMPLIED".
[Error] index.xml:4:43: Invalid value, "http://www.w3.org/TR/xhtml1",
specified for attribute, "xmlns". (default value:
"http://www.w3.org/TR/xhtml1/transitional")

I don't know about namespaces in XML, so I don't know how to treat
these warnings.

Thank you for reading and sorry for my terrible English.

[1] http://www.isi.edu/in-notes/iana/assignments/character-sets

--
Tomohisa Yazaki
Doi Laboratory, Department of Computer Science,
Graduate School of Science and Technology Keio University
yazaki@doi.cs.keio.ac.jp
PGP Finger Print : 0B 4B 86 1A 39 C9 5F 87  A8 76 1D D8 BB 61 D0 2E



diff -rc5 26jul1999/org/w3c/tidy.orig/Clean.java 26jul1999/org/w3c/tidy/Clean.java
*** 26jul1999/org/w3c/tidy.orig/Clean.java	Sat Jul 31 10:28:12 1999
--- 26jul1999/org/w3c/tidy/Clean.java	Tue Aug 31 20:09:13 1999
***************
*** 1195,1200 ****
--- 1195,1238 ----
  
              node = node.next;
          }
      }
  
+     /* remove comments which include "--" */
+     public static void cleanComment(Node node)
+     {
+         while (node != null)
+         {
+             if (node.type == Node.CommentTag)
+             {
+ 	      for(int i = node.start; i < node.end - 1; i++)
+ 		if(node.textarray[i] == '-') {
+ 		  if(node.textarray[i+1] == '-') {
+ 		    Node parent;
+ 		    
+ 		    parent = node.parent;
+ 		    
+ 		    if (parent.last == node)
+ 		      parent.last = node.prev;
+ 		    
+ 		    if (parent.content == node)
+ 		      parent.content = node.next;
+ 		    
+ 		    if (node.prev != null)
+ 		      node.prev.next = node.next;
+ 		    
+ 		    if (node.next != null)
+ 		      node.next.prev = node.prev;
+ 		    
+ 		    break;
+ 		  }
+ 		}
+             }
+ 
+             if (node.content != null)
+                cleanComment(node.content);
+ 
+             node = node.next;
+         }
+     }
+ 
  }
diff -rc5 26jul1999/org/w3c/tidy.orig/Lexer.java 26jul1999/org/w3c/tidy/Lexer.java
*** 26jul1999/org/w3c/tidy.orig/Lexer.java	Sat Jul 31 10:29:24 1999
--- 26jul1999/org/w3c/tidy/Lexer.java	Tue Aug 31 20:11:07 1999
***************
*** 568,577 ****
--- 568,578 ----
  
          if (doctype == null)
          {
              doctype = new Node(Node.DocTypeTag, null, 0, 0);
              doctype.next = root.content;
+ 	    doctype.next.prev = doctype;
              root.content = doctype;
          }
  
          if (configuration.docTypeMode == Configuration.DOCTYPE_USER &&
              configuration.docTypeStr != null)
***************
*** 716,725 ****
--- 717,727 ----
  
          if (doctype == null)
          {
              doctype = new Node(Node.DocTypeTag, null, 0, 0);
              doctype.next = root.content;
+ 	    doctype.next.prev = doctype;
              root.content = doctype;
          }
  
          this.txtstart = this.lexsize;
          this.txtend = this.lexsize;
***************
*** 781,793 ****
              xml.next = root.content;
          }
      
          root.content = xml;
  
          this.txtstart = this.lexsize;
          this.txtend = this.lexsize;
!         addStringLiteral("xml version=\"1.0\"");
          this.txtend = this.lexsize;
  
          xml.start = this.txtstart;
          xml.end = this.txtend;
          return false;
--- 783,811 ----
              xml.next = root.content;
          }
      
          root.content = xml;
  
+ 	String encName = "";
+ 	switch(configuration.CharEncoding) {
+ 	case Configuration.RAW:
+ 	case Configuration.ASCII:
+ 	  encName = "ANSI_X3.4-1968";
+ 	case Configuration.LATIN1:
+ 	  encName = "ISO_8859-1:1987";
+ 	  break;
+ 	case Configuration.UTF8:
+ 	  encName = "UTF-8";
+ 	  break;
+ 	case Configuration.ISO2022:
+ 	  encName = "ISO-2022-JP";
+ 	  break;
+ 	}
+ 
          this.txtstart = this.lexsize;
          this.txtend = this.lexsize;
!         addStringLiteral("xml version=\"1.0\" encoding=\"" + encName + "\"");
          this.txtend = this.lexsize;
  
          xml.start = this.txtstart;
          xml.end = this.txtend;
          return false;
***************
*** 1974,1985 ****
                  c = ' ';
  
                  if (lastc == ' ')
                      continue;
              }
!             else if (foldCase && (map & UPPERCASE) != 0)
                  c += (int)('a' - 'A');
  
              addCharToLexer(c);
          }
  
          if (quotewarning > 10 && seen_gt)
--- 1992,2013 ----
                  c = ' ';
  
                  if (lastc == ' ')
                      continue;
              }
!             else {
! 	      if(configuration.XmlOut) {
! 		Attribute attrib =
! 		  AttributeTable.getDefaultAttributeTable().lookup(name);
! 		if(attrib != null)
! 		  if(attrib.attrchk != null)
! 		    foldCase = true;
! 	      }
! 	      
! 	      if (foldCase && (map & UPPERCASE) != 0)
                  c += (int)('a' - 'A');
+ 	    }
  
              addCharToLexer(c);
          }
  
          if (quotewarning > 10 && seen_gt)
diff -rc5 26jul1999/org/w3c/tidy.orig/Tidy.java 26jul1999/org/w3c/tidy/Tidy.java
*** 26jul1999/org/w3c/tidy.orig/Tidy.java	Sat Jul 31 06:11:54 1999
--- 26jul1999/org/w3c/tidy/Tidy.java	Fri Aug 27 20:43:10 1999
***************
*** 789,798 ****
--- 789,802 ----
  
                  /* ensure presence of initial <?XML version="1.0"?> */
                  if (configuration.XmlOut && configuration.XmlPi)
                      lexer.fixXMLPI(node);
  
+ 		/* remove illegal XML comment tags */
+ 		if (configuration.XmlOut)
+ 		  Clean.cleanComment(node);
+ 
                  if(node.content != null)
                  {
                      Report.reportVersion(errout, "InputStream", lexer.HTMLVersionName());
                      Report.reportNumWarnings(errout, lexer);
                  }
***************
*** 1065,1074 ****
--- 1069,1082 ----
                      }
  
                      /* ensure presence of initial <?XML version="1.0"?> */
                      if (configuration.XmlOut && configuration.XmlPi)
                          lexer.fixXMLPI(node);
+ 
+ 		    /* remove illegal XML comment tags */
+ 		    if (configuration.XmlOut)
+ 		      Clean.cleanComment(node);
  
                      totalwarnings += lexer.warnings;
                      totalerrors += lexer.errors;
  
                      if(node.content != null)
Received on Thursday, 2 September 1999 07:24:50 GMT

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