other related fall backs are;
- aforementioned emptyMessage
- aforementioned The content of the
<$view>widget is displayed if the field or property is missing or empty.- searching for “The content of” reveals how this works in other widgets
- if using the $fill and $slot widgets mention is made of " The TranscludeWidget uses the special slot
ts-missingto specify the content to be rendered if the transclusion target is not defined (i.e. a missing tiddler or a missing field). - The empty $list widget
- Even the $link widget has a degree of fall back behaviour you may otherwise think of as defaults.
We can also mention the fact that if we transclude a transclusion, transclusion “attempts to wikify” the transclusion, and one part of wikification is transclusion, and this will keep occurring to an arbitrary depth.
- This means you could end up transcluding the first transclusion and end up in an infinite loop. There is some protection built in for such cases, but is wise to avoid such cases which can result in infinite loops.
- But judicious use can provide a very powerful design pattern, and helps you reuse code or content effectively only ever having one copy, and this is effectively used by many including the core.
- Keep in mind your macros and procedures could contain transclusions, or items with a fall back and be the cause of a loop.
- If you find you need to use the $wikify widget you may be better using a transclusion or even a function to cause evaluation of underlying wiki text or TiddlyWiki script or filters to occur before the final render.