Couldn't figure out how to use "Procedure" to replace template

[QLXR]

i have tiddler with “_canonical_uri:” field(i used attachement plugin to creat tiddler to link to external file).
what i am tring to do is to create procedure to quick pop the link of this external file.

\procedure link-attachment(attachement_tiddler:"xxx")

{{<<attachement_tiddler>>!!title}}
{{<<attachement_tiddler>>!!_canonical_uri}}
<a href={{<<attachement_tiddler>>!!_canonical_uri}}>{{<<attachement_tiddler>>!!title}}</a>

\end

as you can see with this procedure, it only pop the title, but missing the _canonical_uri field. where did i do wrong…or any other better way to achieve this task.

[EricShulman]

You can’t combine variable references (<<attachement_tiddler>>) and field references (!!title) within a short-form transclusion ({{...}}).

To achieve the results you want, you can use “filtered transclusion”, like this:

\procedure link-attachment(attachement_tiddler:"xxx")
<$text text={{{ [<attachement_tiddler>get[title]] }}}/>
<$text text={{{ [<attachement_tiddler>get[_canonical_uri]] }}}/>
<a href={{{ [<attachement_tiddler>get[_canonical_uri]] }}}>
   <$text text={{{ [<attachement_tiddler>get[title]] }}}/>
</a>
\end

Note the use of the $text widget so that the results of the filtered transclusions are not rendered as tiddler links. Another way to do this is to first use variables to fetch the field values, like this:

\procedure link-attachment(attachement_tiddler:"xxx")
<$let title={{{ [<attachement_tiddler>get[title]] }}}
        uri={{{ [<attachement_tiddler>get[_canonical_uri]] }}}>
<<title>>
<<uri>>
<a href=<<uri>>><<title>></a>
</$let>
\end

a third way to do this is to use the $tiddler widget to set the context, and then you can use simple field transclusions to access the values, like this:

\procedure link-attachment(attachement_tiddler:"xxx")
<$tiddler tiddler=<<attachement_tiddler>>>
{{!!title}}
{{!!_canonical_uri}}
<a href={{!!_canonical_uri}}>{{!!title}}</a>
</$tiddler>
\end

enjoy,
-e

[QLXR]

…lots to learn!!! thanks!

[QLXR]

now if i want to create another procedure and nest this one inside the new one.
new procedure is to add a line [img width = 100% [xxxx.png]] , i came up with below , but didn’t work again.

\procedure screenshot(attachement_tiddler:"xxx", percent:"100%")

<<link-attachment(attachement_tiddler)>>

[img width = <<percent>> [<<attachement_tiddler>>]]

\end

[QLXR]

i figured it out , you actually need use $transclude widget to call procedure inside another proceder…
Tiddlywiki is like a maze to me…

\procedure screenshot(screenshot_tiddler, percent)

<$transclude $variable="attachment" attachement_tiddler=<<screenshot_tiddler>>/>


<<<
<$image source=<<screenshot_tiddler>> width=<<percent>>>
<<<


\end