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UML may be dead but I still use sequence diagrams. They're great for visualising complex code and systems, especially if you're new to a system and are trying t

UML may be dead but I still use sequence diagrams. They're great for visualising complex code and systems, especially if you're new to a system and are trying to gain an understanding the flow of data. I've used mermaid and plant UML and both seem to powerful enough for my use cases, especially when used in conjunction with the preview mode in VS Code.

jmfldn 4y ago
Was messing with mermaid and state diagrams only today. I don't use UML as a whole but some of the diagrams are really useful.
chowells 4y ago
Sequence diagrams are great. Any time there's a multi-stage interaction with multiple independent pieces involved, they're hard to beat for communication. It's not like UML was based on bad ideas. There were just too many cases where the added value was less than the added cost. But when a diagram does add net value it's great to have conventions already.
xh-dude 4y ago
Oh, mermaid looks nice! I hadn’t seen it before. Thanks for mentioning it. If UML tooling had just focused on diagrams, I would not revile UML.
marcosdumay 4y ago
Entity relationship models are good, but people will disagree whether they are UML. Sequence diagrams are useful, but the UML version with a vertical diagram with horizontal lines optimizes for the least necessary use cases; also, the UML one has no space for the participants states. Use cases diagrams are useful, but the UML version just wastes all the space and takes all the useful information out (well, it keeps the actors, could be worse). Class diagrams aren't very useful at all, and when you need them you don't need the formality that is the main point of UML. And finally, the UML designers failed to include any data transformation diagram, because they really did only think in procedural terms.
- eastbound 4y ago
  I’m intrigued by the fact that there exists alternatives to UML’s diagrams? What alternative sequence diagrams are there? Because you are right, we always twist them to include supposedly-orthogonal aspects such as state or actors.
  - marcosdumay 4y ago
    "Alternatives" imply on a formal definition, with strict semantics. IAFAIK, there is no such thing. But most of those kinds of diagram existed before UML, and are designed in very different ways on different contexts. Specifically for sequence diagrams, it's common to replace those lines with bars where you can annotate the state, and it is common to have actors instead of endpoints defining the bars. But if you are relying too heavily on those two, it may be interesting to look at process diagrams (but not strictly BPMN).
billfruit 4y ago
I think statecharts are even more useful than sequence diagrams in documenting behaviour. Statecharts are turing complete, and succinctly visually encode complex behaviour that is going to take reams of text to desribe. Harel et al have done serious, rigourous work in developing statecharts.
SV_BubbleTime 4y ago
> I've used mermaid and plant UML and both seem to powerful enough for my use cases, especially when used in conjunction with the preview mode in VS Code. I haven’t seen Mermaid, I’ll look it up. PlantUML and the live preview in VSCode is one of my favorite things though, I don’t know how I got along without it when planning hierarchical state machines.

jmfldn 4y ago

Was messing with mermaid and state diagrams only today. I don't use UML as a whole but some of the diagrams are really useful.

chowells 4y ago

Sequence diagrams are great. Any time there's a multi-stage interaction with multiple independent pieces involved, they're hard to beat for communication. It's not like UML was based on bad ideas. There were just too many cases where the added value was less than the added cost. But when a diagram does add net value it's great to have conventions already.

xh-dude 4y ago

Oh, mermaid looks nice! I hadn’t seen it before. Thanks for mentioning it. If UML tooling had just focused on diagrams, I would not revile UML.

marcosdumay 4y ago

Entity relationship models are good, but people will disagree whether they are UML. Sequence diagrams are useful, but the UML version with a vertical diagram with horizontal lines optimizes for the least necessary use cases; also, the UML one has no space for the participants states. Use cases diagrams are useful, but the UML version just wastes all the space and takes all the useful information out (well, it keeps the actors, could be worse). Class diagrams aren't very useful at all, and when you need them you don't need the formality that is the main point of UML. And finally, the UML designers failed to include any data transformation diagram, because they really did only think in procedural terms.

eastbound 4y ago
I’m intrigued by the fact that there exists alternatives to UML’s diagrams? What alternative sequence diagrams are there? Because you are right, we always twist them to include supposedly-orthogonal aspects such as state or actors.
- marcosdumay 4y ago
  "Alternatives" imply on a formal definition, with strict semantics. IAFAIK, there is no such thing. But most of those kinds of diagram existed before UML, and are designed in very different ways on different contexts. Specifically for sequence diagrams, it's common to replace those lines with bars where you can annotate the state, and it is common to have actors instead of endpoints defining the bars. But if you are relying too heavily on those two, it may be interesting to look at process diagrams (but not strictly BPMN).

billfruit 4y ago

I think statecharts are even more useful than sequence diagrams in documenting behaviour. Statecharts are turing complete, and succinctly visually encode complex behaviour that is going to take reams of text to desribe. Harel et al have done serious, rigourous work in developing statecharts.

SV_BubbleTime 4y ago

> I've used mermaid and plant UML and both seem to powerful enough for my use cases, especially when used in conjunction with the preview mode in VS Code. I haven’t seen Mermaid, I’ll look it up. PlantUML and the live preview in VSCode is one of my favorite things though, I don’t know how I got along without it when planning hierarchical state machines.