command->command_name_NCName'(' [argument]* ')' ';'argument->XPath_expression|XML_template
Invokes command called command_name_NCName with specified arguments.
Predefined commands are documented in Chapter 3, Predefined commands. A user may define her own commands using macro.
Examples:
set-variable("next",
following-sibling::node()[1][self::text() and
starts-with(., "
")]);
delete-text("^\n", "", $next);
replace(<g:envelope>{translate(., " ", " ")}</g:envelope>);
unwrap-element();