Wsd-mode by Jostein Kjønigsen is a major-mode for Emacs to model textual UML sequence diagrams
and get them rendered automatically with the help of the Web Sequence Diagrams tool (one of the several available textual UML tools , more and more popular every day).
As described in the project GitHub page, the main features of this wsd-mode are:
- proper syntax highlighting for all WSD syntax.
- indentation based on nested constructs and alternative paths.
- supports running Emacs in GUI and the terminal.
- auto-generating diagrams based on source.
- inline rendering in Emacs frames when possible, with fallback to OS or browser for viewing when critical features are unavailable.
And for those interested in modeling UML with Emacs, remember that there is also an Emacs mode for PlantUML