Thanks again, Eric. I'm using the first method as I find it little easier
to follow (especially for later when I may have forgotten what's going on).
I'm considering how to make it more general and not just hardwired to
https://orcid.org
and assume I can use both $(...)$ and $...$ in the same macro... I wonder
whether this is good practice or not... so maybe it would be better to pass
all variables into a macro using the second method with param1=<<value1>>
param2=<<value2>> etc. in the $macrocall.
Take care,
Anthony
On Thursday, 12 November 2020 at 16:00:57 UTC Eric Shulman wrote:
> On Thursday, November 12, 2020 at 6:06:14 AM UTC-8, Anthony wrote:
>>
>> Thanks Eric, I guess the '<currentTiddler>' just creates a filtered list
>> from the current tiddler and whether text is displayed depends on this
>> being null or not.
>>
>
> "[<currentTiddler>has[death-date]]" means "if the current tiddler has a
> non-blank death-date field"
>
> Without using <currentTiddler> at the beginning of the filter, then filter
> would be applied to ALL tiddlers by default,
> and "has[death-date]" would produce output for every tiddler with a
> non-blank death-date field, not just the current one.
>
> Now, using the same methodology, I'm trying to construct an external link
>> and tried:
>>
>> <$list filter="[<currentTiddler>has[orcid]]">
>> ''ORCID'': [[{{!!orcid}}|https://orcid.org/{{!!orcid}}]]
>> </$list>
>>
>
> The problem here is that TiddlyWiki syntax doesn't "nest". That is, you
> can't use one kind of syntax
> such as transclusion -- {{!!orcid}} -- within another, such as a link --
> [[text|url]].
>
> You can, however, *construct* the link syntax by using a macro, like this:
> \define mylink() [[$(this_orcid)$|https://orcid.org/$(this_orcid)$]]
>
> <$list filter="[<currentTiddler>get[orcid]]" variable="this_orcid">
> ''ORCID'': <<mylink>>
> </$list>
>
> Note that the filter uses "get[orcid]" rather than "has[orcid]". This not
> only tests to see if the "orcid" field is non-blank, but also fetches it's
> value, which is set into the "this_orcid" variable. Then, the
> $(this_orcid)$ syntax within the macro does a string substitution, based on
> the current value of the "this_orcid" variable.
>
> Note also that the $(...)$ syntax can only be used within a macro. Keep
> in mind that macros only do two things:
>
> 1. replace instances of $(...)$ with values from variables, where the
> variables are defined *outside* of the macro
> 2. replace instances of $...$ with values from parameters, where the
> parameters are passed into the macro
>
> All other processing of the macro output is performed by the calling
> context. In the above example, this means the resulting link syntax --
> [[foo|https:/orcid.org/foo]] -- is parsed and wikified after being
> "returned" from the macro.
>
> Another point about macro syntax: if you want to use the "parameter"
> method to pass the "this_orcid" value into the macro, you would write
> something like this:
> \define mylink(id) [[$id$|https://orcid.org/$id$]]
>
> <$list filter="[<currentTiddler>get[orcid]]" variable="this_orcid">
> ''ORCID'': <$macrocall $name="mylink" id=<<this_orcid>> />
> </$list>
>
> Note the use of the <$macrocall> widget to invoke the "mylink" macro with
> the "id" parameter set to the current value of the "this_orcid" variable.
> This is needed because you can't nest the variable reference --
> <<this_orcid>> within the shorthand <<mylink>> syntax; i.e., you CANNOT
> write <<mylink <<this_orcide>>>> because the closing ">>" of the variable
> reference would be seen as ending the enclosing macro, with the second ">>"
> being left over to "fall out" as displayed text.
>
> TiddlyWiki syntax is consistent, but somewhat less flexible than other
> languages. While this may be a little confusing at first, once you get
> used to it's peculiarities, it becomes easier.
>
>
>> Apologies, I can't figure out how to format the code in monospace in a
>> grey-background box.
>>
>
> That is a feature of the old GoogleGroups editing interface that they have
> inexplicably left out of the new interface. To view this group using the
> old interface (which I prefer), you can use a URL like this:
>
> https://groups.google.com/forum/?oldui=1#!forum/tiddlywiki
>
> enjoy,
> -e
>
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