A way of including or excluding sections in the DTD is to use conditional sections. Conditional sections are of most use when linked to a parameter entity reference, and may only be used in an external DTD subset. The two conditional section statements are IGNORE and INCLUDE.

<![ IGNORE [

markup declarations

]]>

<![ INCLUDE [

markup declarations

]]>

<!ENTITY % draft "INCLUDE">
<!ENTITY % final "IGNORE">
<![%draft;[
<!ELEMENT book (title,author,summary)>
]]>
<![%final;[
<!ELEMENT book (comments*,title,author,summary)>
]]>
<!ELEMENT comments (#PCDATA)>
<!ELEMENT title (#PCDATA)>
<!ELEMENT author (#PCDATA)>
<!ELEMENT summary (#PCDATA)>

Rules:

• Conditional sections may only be used in external DTD subsets.
• Conditional sections must wrap around entire declarations.

Note:

• The IGNORE declaration takes precedence over INCLUDE. If an IGNORE statement is nested inside an INCLUDE statement, the contents of the IGNORE statement will still be ignored.

XML Guide TOC

XML Declaration
DOCTYPE Declaration & DTDs
ELEMENT Type Declaration
ATTLIST Declaration
ENTITY Declaration
NOTATION Declaration
CDATA Section
Processing Instruction
Conditional Section
Comments

Glossary