-- <?=$!variablename?> will output the variable "variablename" but not HTML-escaped
-- <?=s,$!variablename,My %s text?> will insert the variable "variablename" into the translated text but not HTML-escaped
-- <?=s,"some data",My %s text?> will insert "some data" into the translated text
-- <?=s,!"some data",My %s text?> will insert "some data" into the translated text literally (not HTML-escaped)
-
-- <? if($variable) { ?>
- Output/execute the text until "<? } ?>" only if $variable not null or Boolean.FALSE.
-
-- <? foreach($variable) { ?>
+- <? if($variable) { ?> ... <? } ?>
+ Output/execute the text until "<? } ?>" only if $variable is Boolean.TRUE (<=> !Boolean.FALSE) or not null.
+- <? if(...) { ?> ... <? } else { ?> ... <? } ?>
+
+- <? foreach($variable) { ?> ... <? } ?>