UML and its manipulations are only a relatively small thing -- the Unified Process covers much more than that. So, as a question on process, OO or functional d

UML and its manipulations are only a relatively small thing -- the Unified Process covers much more than that. So, as a question on process, OO or functional does not matter much: the software is treated really as modules or parts. Whether those are composed of lists or objects, methods or functions, is a minor concern. Process deliberately works at a higher level. There is some specialisation to OO, but translating it to FP would seem essentially straightforward. But as a question on that particular sub-area, it is valid and interesting, and there does not seem to be such a functional specialisation. Perhaps there is a way to answer by looking back to the history of the Unified Process. A substantial basis of it was developed by Jacobson while working at Ericsson on phone switches etc. And that was the same place and same kind of work where Erlang was later created. So maybe investigating how to use Erlang might lead to some approaches.