xsl:character-map
Defines a named character map for use during serialization.
Category: declaration
Content: (
xsl:output-character*
)
Permitted parent elements:
xsl:package
; xsl:stylesheet
; xsl:transform
Attributes
|
|
|
The name of the character map, which can be
referenced from the |
|
|
|
Character maps may be assembled
from other character maps using the |
Notes on the Saxon implementation
Using character maps may be expensive at run-time. Saxon currently makes no special attempts to optimize their use: if character maps are used, then every character that is output will be looked up in a hash table to see if there is a replacement string.
Details
The xsl:character-map element contains a set of xsl:output-character
elements each of which defines the output representation of a given Unicode
character. The character is specified using the character
attribute, the string which is to replace this character on serialization is
specified using the string attribute. Both attributes are
mandatory.
The replacement string is output as is, even if it contains special
(markup) characters. So, for example, you can define
<xsl:output-character character=" "
string=" "/> to ensure that NBSP characters are output
using the entity reference .
Character maps allow you to produce output that is not well-formed XML, and they
thus provide a replacement facility for disable-output-escaping. A
useful technique is to use characters in the Unicode private use area (xE000 to
xF8FF) as characters which, if present in the result tree, will be mapped to
special strings on output. For example, if you want to generate a proprietary
XML-like format that uses tags such as <!IF>,
<!THEN>, and <!ELSE>, then you could
map these to the three characters xE000, xE001, xE002 (which you could in turn
define as entities so they can be written symbolically in your stylesheet or
source document).
Character maps are preferred to disable-output-escaping because they
do not rely on an intimate interface between the transformation engine and the
serializer, and they do not distort the data model. The special characters can
happily be stored in a DOM, passed across the SAX interface, or manipulated in
any other way, before finally being rendered by the serializer.