So to transclude a tiddler through a template we can do this:
<$tiddler tiddler="contentTiddler">
<$transclude $tiddler="templateTiddler"/>
</$tiddler>
or
{{contentTiddler||templateTiddler}}
but what if the content I want is stuff that’s been defined in a variable?
The following doesn’t work but it kinda shows what I’m trying to do:
<$let content="literal stuff I want trancluded through the templateTiddler">
{{<<content>>||templateTiddler}}
</$let>
Hello @hoopyfrood
maybe this link Grok Tiddlywiki can help - Chapter 4 Transclusion
Update
I think this works
transclusion.json (373 Bytes)
Looks like @etardiff beat me to it. Mines probably wrong anyhow 
If your content is anything more complex than a literal value, you need to switch to filtered transclusion. The docs include an example of a template used to transclude filter results (spaces added below for clarity):
{{{ [tag[mechanism]] || TemplateTitle }}}
You can do the same with a single variable by using the filter syntax for variables:
{{{ [<content>] || TemplateTitle }}}
This short form can be convenient, but there are also alternatives:
<$tiddler tiddler=<<content>>> <!-- assuming <<content>> is a single title -->
<$transclude $tiddler="TemplateTitle"/>
</$tiddler>
For multiple titles, we can also rewrite the first example as a $list:
<$list filter="[tag[mechanism]]" template="TemplateTitle" />
or (taking advantage of the fact that $list widgets set the <<currentTiddler>> value for each result, by default)
<$list filter="[tag[mechanism]]">
<$transclude $tiddler="TemplateTitle" />
</$list>
or even
<$list filter="[tag[mechanism]]">
{{||TemplateTitle}} <!-- transcluding <<currentTiddler>> when the content tiddler isn't specified -->
</$list>
I tried those and it resulted in:
“Missing tiddler “literal value of the variable I wanted transcluded” – click to create”
I know there was a discussion about virtual tiddlers that I couldn’t really follow, is that something that could apply here? (using a not-real tiddler to hold a variable’s value that can be used in the $tiddler widget?)
So I can’t really put the variable on its own tiddler to get transcluded through the template like that, its contents are more complicated, so I guess I’m asking more like how to call a variable through a template without putting it as the sole text of a tiddler?
a little more specifically, what I’m trying to do is like:
<$let content={{{ [<filter run that gets a fragment from the text field of a tiddler>] }}} >
{{<<content>>||templateTiddler}}
</$let>
Are you using $:/core/ui/ViewTemplate/body/default as your transclusion template? If so, that’s what I would expect to see for any values that don’t correspond to extent tiddler titles.
I think the term “virtual tiddler” is most commonly used to refer to “missing” tiddlers opened in the story river (e.g. by following a link); this lets you use a custom ViewTemplate instead of (or in addition to) $:/core/ui/ViewTemplate/body/default to display information pertaining to that title even when the title isn’t a “real” tiddler with its own field content. You could theoretically do the same thing with a $list template or filtered transclusion template, but that template would have to be designed to show information from/about tiddlers that do exist. For instance, you can test this example on TW-com:
<$let myVar="TiddlyBlink">
<$list filter="DailyNotes [<myVar>] [tag[HelloThere]]">
!!! <$link />
Linked from
<<list-links "[<currentTiddler>backlinks[]]">>
---
</$list>
</$let>
Here you can see that the first two values in the list filter produce titles that don’t actually exist as real tiddlers — but they can still be used as input values for the template. If you moved everything between the $list widget tags into a separate tiddler MyTemplate, you could use it with any of the syntax options I mentioned above.
Does this help? If not, I’m happy to try to help you figure out a solution, but it would be easier if you could give us more specific details about your use-case and what you’d expect to see if your variable doesn’t correspond to a real tiddler title.
I just put this in the reply to Sunny but what I’m trying to do is kind of like:
the filter run is using split and trim operators to get a specific fragment of the text field, and I want that fragment of text to be rendered through what I have in a template tiddler
I can’t think of any reason why that wouldn’t work — unless your template tiddler includes field transclusions like {{!!my-field}}, which obviously won’t show up if the content “tiddler” doesn’t exist and/or doesn’t have that field.
oooh yes my template is trying to get text from the {{!!text}} field, which doesn’t exist in a variable… I think I’m going to need to change the template itself a bit. Thanks for pointing that out!
{{!!title}} or <<currentTiddler>> should be safe to use in any template — they refer to the current value, whether it’s a real tiddler or not.
