The IMPORT tag, which must be placed inside a
        RULES tag, loads all rules defined in a given ruleset
        into the current ruleset; in other words, it has the same effect as
        copying and pasting the imported ruleset.
The only required attribute DELEGATE must be
        set to the name of a ruleset. To import a ruleset defined in the current
        mode, just specify its name. To import a ruleset defined in another
        mode, specify a name of the form
        mode::ruleset
One quirk is that the definition of the imported ruleset is not
        copied to the location of the IMPORT tag, but rather
        to the end of the containing ruleset. This has implications with
        rule-ordering; see the section called “Rule Ordering Requirements”.
Here is an example from the PHP mode, which extends the inline JavaScript highlighting to support embedded PHP:
   <RULES SET="JAVASCRIPT+PHP">
   <SPAN TYPE="MARKUP" DELEGATE="php::PHP">
       <BEGIN><?php</BEGIN>
       <END>?></END>
   </SPAN>
   <SPAN TYPE="MARKUP" DELEGATE="php::PHP">
       <BEGIN><?</BEGIN>
       <END>?></END>
   </SPAN>
   <SPAN TYPE="MARKUP" DELEGATE="php::PHP">
       <BEGIN><%=</BEGIN>
       <END>%></END>
   </SPAN>
   <IMPORT DELEGATE="javascript::MAIN"/>
</RULES>