I had the need for one, so I created a Python script to migrate an existing DokuWiki into TiddlyWiki.
This script will process the plain text storage files DokuWiki uses, translating that content to the TiddlyWiki syntax style and outputting an importable json.
Additionally it has the ability to organize that content in a format more applicable to TiddlyWiki by creating a Table of Contents and developing top level categories based on the DokuWiki organization of pages.
The syntax recognition is fairly complete (covered everything I used and a bit more), and fairly bulletproof.
Still some things I'm still working on, but wanted to share. Figure this is a pretty niche tool, but there it is.
Project page here:
Feedback welcome or any contributions