Structured Activity Types - specifically: Loop Node

[nomisge]

Is your feature request related to a problem?

I would like to create an activity diagram containing a 'for each loop'.
I would like my students to translate an idea given by the activity diagram into e.g. python code. There the loop would look like for obj in my_list: ...
I haven't found a good way to do this in gaphor yet.

Describe the solution you'd like

I would like gaphor to support 'structured activity types'. There seem to be several:
https://sparxsystems.com/enterprise_architect_user_guide/14.0/model_domains/loop_and_conditional_nodes.html

In my case I would like to have a 'loop node'. A more elaborate example is given at:
https://stackoverflow.com/questions/15792687/loop-in-uml-activity-diagram-using-a-region

It probably is best to have a single structured activity type, where you can toggle up to three partitions (setup, test, body). Like within a class diagram, where you can toggle attributes and operations.

Describe alternatives you've considered

For regular loops I could use simple flow and decision nodes (https://www.softwareideas.net/uml-activity-diagram-loop),
but I wouldn't know how to express a for-each loop nicely with that.

What are your thoughts about that?
Is this easy to implement (happy to help, any way I can)?
Did I miss something and my goal can already be reached somehow?

[amolenaar]

Hi @nomisge, thank you for your request. We need to implement a bit.

It would be much appreciated if you can help out. In short:

1. Set up a development environment.
2. Implement the necessary bits from the UML 2.5 spec (Structured Actions) (search for "LoopNode").
3. Generate the model (poe uml).
4. Create a LoopNodeItem in gaphor/UML/actions and add it to the toolbox.
5. Have a look at the docs for features to implement (e.g. grouping).

To unstuck you, for now you can get away with defining a stereotype and apply that to an action:

A bit of CSS will make sure the line is properly dashes:

action[appliedStereotype.classifier.name="loop"] {
 dash-style: 11 5;
 justify-content: start;
}

loop.gaphor.zip