Here's my tutorial example:
Preamble
<!-- this is the test on the manual page -->
Always issue this text.
<?if condition='html'>
Issue this text if 'condition=html' is given on the command line.
<?elif condition='pdf|ps'>
Issue this text if 'condition=pdf' or 'condition=ps'
is given on the command line.
<?else>
Otherwise issue this text.
<?fi>
Always issue this text.
<!-- this ends the test on the manual page -->
<?if condition='foo'>
Should display only if condition is foo
<?elif condition='baz'>
Should display only if condition is baz
<?else>
Should display only if condition is not foo and not baz
<?fi>
<?if not condition='bar'>
Should display only if condition is not bar
<?if cond2='on'>
This should be displayed only when cond2 is on.
<?fi>
<?else>
Should display only if condition is bar
<?fi>
Postamble.
I knew something bothered me about this, and the problem just smacked
me upside the head: