PlantUML Rendering Constraint

[guard-who]

sd-generate/src/Modelling/StateDiagram/Example.hs

Line 874 in 6dcb0e7

{- was added due to failures in PlantUML front end

illustrates the issue with PlantUML rendering. The reason is that PlantUML can not support any connections from a node outside a concurrent (region) state to a node in the concurrent state (no matter entering in or leaving out), even though it is permitted in UML state diagrams, which is referred to here https://forum.plantuml.net/4336/state-diagram-the-state-cannot-be-used-here or plantuml/plantuml#2216. A direct connection with the concurrent state is permitted.

Currently, no proper alternative way to solve the rendering constraint has been found yet.

[guard-who]

Besides the above one, there are some other constraints recorded here:
https://github.com/fmidue/sd-generate/blob/main/plantUML/document.txt