Subject: Re: [xsl] Problems matching end-of-line character From: David Carlisle <davidc@xxxxxxxxx> Date: Wed, 10 Aug 2005 23:59:38 +0100 |
> Specifically whats the difference > between a character reference, and an entity reference? semantically one references an entity (something that os declared with an <!ENTITY declaration (like EOL in your case) and the other refernces a character by unicode number, these aren't declared anywhere, they are just core syntax. syntactically an entity reference is & followed by a name folowed by a semi colon, a character reference is & followed by a # follwed be either a decimal or hex number followed by ;. The important thing here is when the references get replaced by the objects they reference. If you go <!ENTITY foo "&bar;"> then the replacement text of foo is &bar; (that is, 5 characters). when &foo; is used it is replaced by those characters and parsing restarts from the start of the replacement text, so at that point &bar; is parsed as an entity reference and replaced by its definition. (s it's not an error to refer to an undefined entity in an entity definition if that entity is never referenced. If bar is not defined that is not an error unless &foo; is used. Conversely <!ENTITY foo " "> character references are expanded inline, the replacement text of foo is the single character with number 10. in the case of white space normalisation in attributes, character references play a special role to quote the white space, but entity references play no role at all they are expanded before the normalisation starts. more involved examples of the interplay of this timing difference in http://www.w3.org/TR/REC-xml/#sec-entexpand David ________________________________________________________________________ This e-mail has been scanned for all viruses by Star. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk ________________________________________________________________________
Current Thread |
---|
|
<- Previous | Index | Next -> |
---|---|---|
Re: [xsl] Problems matching end-of-, Kenneth Stephen | Thread | [xsl] Opening with different, jeb501 |
Re: [xsl] Problems matching end-of-, Kenneth Stephen | Date | Re: [xsl] Joining sibling elements, Mukul Gandhi |
Month |