Joshua, While you await an answer, I just thought I would point out that once you achieve what you ask, if the current journal entry does not exist, you will have a new tiddler open with no content. That would be OK except we often want such new journal entries to have particular tags etc...
What I have done instead is to make a New Journal button visible in every tiddler, or in the sidebar or somewhere else on the page. Pressing this button opens the New Journal tiddler creating and adding tags as desired but if today's already exists opens today's Journal tiddler. This suggestion does not quite answer your question, but may be a better approach. Regards Tony -- 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/2e5b4f46-4eb8-41d2-982f-73374924205e%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.

