The key thing to understand here is that unknown variables get assigned a
value of "", i.e. a zero length string. The is[blank] operator checks
specifically for zero length strings.
So <<missingvar>> won't show anything when wikified as you are rendering a
zero length string, but the filter result is not an empty title list but
rather has one member, a zero length string.
On Wednesday, November 11, 2020 at 12:16:31 AM UTC+1, TW Tones wrote:
>
> Saq,
>
> Thanks, I did understand your point, and expected <local-value> to be
> empty and could not make it so, Although '<<local-value>>' always returned
> '' when empty.
> But as I read in the following example it appears to be blank? thus if !is
> [blank] no value will be returned and else is engaged.
>
> *Perhaps we can say an empty run is blank not empty?*
> Thus as you suggested !is[blank] changes blank to empty.
>
> Thus in the case of [<varname>] an empty varname returns blank not empty.
>
> I have decided to take another path, dynamically create a macro eg
> "\define setting() value"
>
> This reply was Posted now, I forgot to post it yesterday.
>
> Thanks for you help
> Tones
>
> On Tuesday, 10 November 2020 14:50:25 UTC+11, Saq Imtiaz wrote:
>>
>> You may have missed my point. I don't believe your first filter run ever
>> returns an empty title list.
>>
>> Try this:
>> {{{ [<local-value>!is[blank]] ~[<global-config-value>!is[blank]] ~[<
>> config-default>] }}}
>>
>> For a hint try this in Advanced Search -> Filters:
>> [<foo>]
>> It should tell you there is 1 match.
>>
>> You can also test:
>> {{{ [<local-value>count[]] }}}
>>
>> Your first filter run must return no titles in order for the else clause
>> to be triggered.
>>
>> If none of that works, please post the actual vs expected outcome of:
>> {{{ [<local-value>] [<global-config-value>] [<config-default>] }}}
>>
>
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