In this discussion Feedback on documentation of filter operators - #12 by etardiff a combobox is used to get values from a particular field.
I would like to create a similar combobox by using a procedure.
Can someone please tell me where I’m going wrong.
In filter syntax, the brackets indicate how a filter parameter is to be processed:
use square brackets for literal values; e.g., [tag[sometext]]
use angle brackets for variable references; e.g., [tag<somevar>]
use curly brackets for tiddler field/index references; e.g. [tag{tiddlertitle!!somefield}] or [tag{tiddlertitle##someindex}]
unlike wikitext syntax, the brackets in filter syntax are not doubled.
In addition:
if a field or index reference is for the current tiddler, the tiddlertitle portion is omitted (i.e., use [tag{!!somefield}] or [tag{##someindex}])
if the reference is to a tiddler’s text field, the !!somefield portion can be optionally omitted (i.e, [tag{tiddlertitle}] is the same as [tag{tiddlertitle!!text}]
Thus, for your specific use-case, you need to change:
One tip on this is that wikitext also permits html, as a result we need to differentiate between html tags <div> and other tiddlywiki script <<varname>> similarly someone may wish to use curly braces { group content} so we use the less likely {{ transclusion }} or {{{ filtered transclusion }}} for what I call TiddlyWiki Script. Similarly for square braces [ ].
When used inside a filter, the filter is delimited already however you provide the filter so we need not double brace everything. We actualy discussed this recently - cant find yet.