Hi David Try:
[[VAR_NAME]] +[is[variable]addsuffix[ is a variable]] ~[[Undefined variable or macro 'VAR_NAME']] [[currentTiddler]] +[is[variable]addsuffix[ is a variable]] ~[[Undefined variable or macro ‘currentTiddler']] You can try out these examples in the “filter” tab of advanced search in the prerelease: https://tiddlywiki.com/prerelease/#%24%3A%2FAdvancedSearch <https://tiddlywiki.com/prerelease/#$:/AdvancedSearch> Best wishes Jeremy. > On 25 Feb 2019, at 20:49, David Nebauer <[email protected]> wrote: > > Thanks, Jeremy. For future reference, would you mind showing how that > subfilter could be used to test for the existence of a particular variable or > macro, say 'VAR_NAME', and display the text "Undefined variable or macro > 'VAR_NAME'" if it is not found. > > -David > > On Monday, 25 February 2019 22:39:23 UTC+9:30, Jeremy Ruston wrote: > Hi David > > I think you’re right: there is no way to test for the existence of a variable > whose value is blank. I’ve added an [is[variable]] subfilter operator for > v5.1.20 to address this: > > https://github.com/Jermolene/TiddlyWiki5/commit/36e76429b1a1d4638374d513430393db5693b932 > > <https://github.com/Jermolene/TiddlyWiki5/commit/36e76429b1a1d4638374d513430393db5693b932> > > Best wishes > > Jeremy. > > >> On 25 Feb 2019, at 12:34, David Nebauer <[email protected] <>> wrote: >> >> As I understand it, if you attempt to call an undefined macro the call fails >> silently, with nothing displaying in the tiddler to alert users. This occurs >> regardless of the calling method, i.e., >> >> <<not-a-real-macro>> >> or >> <$macrocall $name="not-a-real-macro"/> >> >> Is there a technique for checking whether a macro is defined, and displaying >> a message in the tiddler if the macro is not defined? >> >> Ideally, the test would not just check for output from the macro, since >> there might be valid circumstances where a macro produces no output. >> >> -David >> >> -- >> You received this message because you are subscribed to the Google Groups >> "TiddlyWiki" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <>. >> To post to this group, send email to [email protected] <>. >> Visit this group at https://groups.google.com/group/tiddlywiki >> <https://groups.google.com/group/tiddlywiki>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/tiddlywiki/1ecc0c93-5932-41bb-9634-3eca9daf26c1%40googlegroups.com >> >> <https://groups.google.com/d/msgid/tiddlywiki/1ecc0c93-5932-41bb-9634-3eca9daf26c1%40googlegroups.com?utm_medium=email&utm_source=footer>. >> For more options, visit https://groups.google.com/d/optout >> <https://groups.google.com/d/optout>. > > > -- > You received this message because you are subscribed to the Google Groups > "TiddlyWiki" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <mailto:[email protected]>. > To post to this group, send email to [email protected] > <mailto:[email protected]>. > Visit this group at https://groups.google.com/group/tiddlywiki > <https://groups.google.com/group/tiddlywiki>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/tiddlywiki/49d883c4-f2f7-434b-aaf7-5b1f0d21a29b%40googlegroups.com > > <https://groups.google.com/d/msgid/tiddlywiki/49d883c4-f2f7-434b-aaf7-5b1f0d21a29b%40googlegroups.com?utm_medium=email&utm_source=footer>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- You received this message because you are subscribed to the Google Groups "TiddlyWiki" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/tiddlywiki. To view this discussion on the web visit https://groups.google.com/d/msgid/tiddlywiki/85A338A3-D5E5-4D54-94CA-6471D647D442%40gmail.com. For more options, visit https://groups.google.com/d/optout.
