SAXONICA

Saxon Documentation
Full Contents
About Saxon
Changes in this Release
Conditions of Use
Using XSLT 2.0
Using XQuery
Handling Source Documents
XML Schema Processing
The XPath API
Saxon on .NET
Extensibility
Saxon Extensions
| Introduction
| EXSLT Extensions
| Extension attributes (XSLT only)
| Additional serialization parameters
| Extension functions
» | Extension instructions
Sample Saxon Applications
The Saxon SQL Extension
XSLT Elements
XPath 2.0 Expression Syntax
Function Library
Standards Conformance

# saxon:doctype

The `saxon:doctype` instruction is used to insert a document type declaration into the current output file. It should be instantiated before the first element in the output file is written. It must be used only when writing a final result tree (not a temporary tree) and only when writing text nodes. The reason for these restrictions is that saxon:doctype writes directly to the serialized output stream (internally it uses disable-output-escaping to achieve this). It is not possible to represent a doctype declaration as a node on a temporary tree.

The `saxon:doctype` instruction takes no attributes. The content of the element is a template-body that is instantiated to create an XML document that represents the DTD to be generated; this XML document is then serialized using a special output method that produces DTD syntax rather than XML syntax.

If this element is present the `doctype-system` and `doctype-public` attributes of `xsl:output` should not be present. Also, the `standalone` attribute of `xsl:output` should not be used. This is because the DOCTYPE declaration generated by `saxon:doctype` is output as a text node using disable-output-escaping, and thus appears to the serializer as a document that is not well-formed; the use of `standalone` with such documents is prohibited by the W3C serialization specification.

The generated XML document uses the following elements, where the namespace prefix "dtd" is used for the namespace URI "http://saxon.sf.net/dtd":

dtd:doctype | Represents the document type declaration. This is always the top-level element. The element may contain dtd:element, dtd:attlist, dtd:entity, and dtd:notation elements. It may have the following attributes: name (mandatory) The name of the document type system The system ID public The public ID
dtd:element | Represents an element type declaration. This is always a child of dtd:doctype. The element is always empty. It may have the following attributes: name (mandatory) The name of the element type content (mandatory) The content model, exactly as it appears in a DTD, for example content="(#PCDATA)" or content="( a | b | c)*"
dtd:attlist | Represents an attribute list declaration. This is always a child of dtd:doctype. The element will generally have one or more dtd:attribute children. It may have the following attributes: element (mandatory) The name of the element type
dtd:attribute | >Represents an attribute declaration within an attribute list. This is always a child of dtd:attlist. The element will always be empty. It may have the following attributes: name (mandatory) The name of the attribute type (mandatory) The type of the attribute, exactly as it appears in a DTD, for example type="ID" or type="( red | green | blue)" value (mandatory) The default value of the attribute, exactly as it appears in a DTD, for example value="#REQUIRED" or value="#FIXED 'blue'"
dtd:entity | Represents an entity declaration. This is always a child of dtd:doctype. The element may be empty, or it may have content. The content is a template body, which is instantiated to define the value of an internal parsed entity. Note that this value includes the delimiting quotes. The xsl:entity element may have the following attributes: name (mandatory) The name of the entity system The system identifier public The public identifier parameter Set to "yes" for a parameter entity notation The name of a notation, for an unparsed entity
dtd:notation | Represents a notation declaration. This is always a child of dtd:doctype. The element will always be empty. It may have the following attributes: name (mandatory) The name of the notation system The system identifier public The public identifier

Note that Saxon will perform only minimal validation on the DTD being generated; it will output the components requested but will not check that this generates well-formed XML, let alone that the output document instance is valid according to this DTD.

Example:

    <xsl:template match="/">
      <saxon:doctype xsl:extension-element-prefixes="saxon">
      <dtd:doctype name="booklist"
            xmlns:dtd="http://saxon.sf.net/dtd" xsl:exclude-result-prefixes="dtd">
        <dtd:element name="booklist" content="(book)*"/>
        <dtd:element name="book" content="EMPTY"/>
        <dtd:attlist element="book">
          <dtd:attribute name="isbn" type="ID" value="#REQUIRED"/>
          <dtd:attribute name="title" type="CDATA" value="#IMPLIED"/>
        </dtd:attlist>
        <dtd:entity name="blurb">'A <i>cool</i> book with &gt; 200 pictures!'</dtd:entity>
        <dtd:entity name="cover" system="cover.gif" notation="GIF"/>
        <dtd:notation name="GIF" system="http://gif.org/"/>
      </dtd:doctype>
      </saxon:doctype>
      <xsl:apply-templates/>
    </xsl:template>

Although not shown in this example, there is nothing to stop the DTD being generated as the output of a transformation, using instructions such as `xsl:value-of` and `xsl:call-template`. It is also possible to use `xsl:text` with `disable-output-escaping="yes"` to output DTD constructs not covered by this syntax, for example conditional sections and references to parameter entities.

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