foo: <tmpl_if true>foo</tmpl_if>.
bar: <tmpl_if true>bar</tmpl_if>.
black: <tmpl_if true>dark<tmpl_else>light</tmpl_if>.
white: <tmpl_if false>dark<tmpl_else>light</tmpl_if>.

<tmpl_unless undef>sam was here.</tmpl_unless>
<tmpl_unless false_loop>sam wuz here.</tmpl_unless>

bing: <tmpl_if true_loop>bong</tmpl_if>.
bing: <tmpl_if false_loop>boom</tmpl_if>.

<tmpl_loop true_loop><tmpl_var var></tmpl_loop>
<tmpl_loop false_loop><tmpl_var var></tmpl_loop>

<tmpl_loop values>
  <tmpl_if even>
     <tmpl_var value> is even
  <tmpl_else>
     <tmpl_var value> is odd
  </tmpl_if>
</tmpl_loop>