if xpath|perl-code command-block [ elsif command-block ]* [ else command-block ]
Execute command-block if a given xpath or perl-code expression evaluates to a non-emtpty node-list, true boolean-value, non-zero number or non-empty literal. If the first test fails, check all possibly following elsif conditions and execute the corresponding command-block for the first one of them which is true. If none of them succeeds, execute the else command-block (if any).
Example 18. Display node type
def node_type %n {
foreach (%n) {
if ( . = self::* ) { # XPath trick to check if . is an element
echo 'element';
} elsif ( . = ../@* ) { # XPath trick to check if . is an attribute
echo 'attribute';
} elsif ( . = ../processing-instruction() ) {
echo 'pi';
} elsif ( . = ../text() ) {
echo 'text';
} elsif ( . = ../comment() ) {
echo 'comment'
} else { # well, this should not happen, but anyway, ...
echo 'unknown-type';
}
}
}