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Comment by agumonkey | Hacker News Reader

I try hard not to be an immature commentator, but I've yet to see anybody think around a UML tool. And it's somehow ironic that I shut off 99.999% of the UML/OO world because reading anything about lisp/haskell/forth/prolog made my brain think a dozen orders of magnitude more than anything I did with UML, which finally was an effort that felt going somewhere.

All I remember about UML is useless semantic debates (activity vs states on time axis) or shallow bikesheeding sessions about UML profiles (we actually had hours "talking" about whether we should use plain or hollow dash.. I mean really) for clueless clients stuck in manual FTP workflows.

It's possible that these people were operating at higher thinking levels than I was capable of doing.. but even if so, I'd rather enjoy my own quirks and live in picolisp.

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I can remember deciding protocols (actual protocols, not data types) around message sequence diagrams, and a lot of people certainly think around entity-relationship models (yeah, those are UML too).

You will notice that those aren't the design of OO systems that UML was created for, but they exist. Also, there are better diagrams for protocols than message sequence UML, but those don't have good tooling.

Besides those, use-case diagrams are nice too. They also emanate that strong feeling that they don't describe the correct idea (just like message sequence for protocols), but I don't know of a better replacement, just worse ones. People try to replace this one with all kinds of canvas too, but those just bring different problems.

> a lot of people certainly think around entity-relationship models (yeah, those are UML too).

Chen notation entity-relationship models are about 20 years older tha the first work on UML. UML class diagram notation is sometimes pressed into service for ER Modeling by people already invested in UML, but that’s about the extent of the relationship.

> Besides those, use-case diagrams are nice too. They also emanate that strong feeling that they don't describe the correct idea (just like message sequence for protocols), but I don't know of a better replacement, just worse ones.

The problem I have with Use Case models is that they combine abstract requirements/domain modeling with implementation design in an opinionated OO way. They may be the best way to do those together in one diagram, but I just think that’s usually a bad idea to do. For the first part, I think Level 0 Yourdon-style DFDs are a better tool; for the second, if you need OO-focused diagrams, I would probably go with UML class diagrams, recognizing that interactions are nouns in the domain.

> Also, there are better diagrams for protocols than message sequence UML, but those don't have good tooling.

Interesting. What would those be? TIA

When people get to publish papers in distributed computing, they always use free-hand drawn graphs, not UML.

The format varies a lot, but there is a popular one where time usually flows at the horizontal, lanes do not necessarily go through all of the diagram, the arrows are more angular, and there are very diverse conventions on the message label. The angular arrows are a very impactful change by themselves.

There are also data flow diagrams, when you don't need to represent causality.

protocols design would have been a step up already, but I find sequence diagram barely adequate here, better than nothing but really a disgrace compared to a lot of tools we use (property based testing for instance, or state space like proofs, instead of ad-hoc manual drawing you know)

I have never met anybody that can think around property based testing. Your tools are stuff people write after thinking, not while it.

Why not having a middle ground, throw agents and signals. See how the protocol behave and what sequences led to absurd states through PBT

I think this is a good comment, not immature. I think I understand where you're coming from. I've been a Common Lisp fan for a while. As has been said by others who've used it, even if you don't use it in your daily work, it changes your thinking. I think UML was (is still for a few?) the standard way to define structure and interactions. UML seems to me to have a high amount of ceremony. For something as complex as say, a jet engines control system, perhaps this is reasonable? .. I also like the idea of enjoying "my own quirks". This fits with the dedication in SICP, https://web.mit.edu/alexmv/6.037/sicp.pdf .

  I think that it’s extraordinarily important that we in computer science keep fun in computing

A great idea. The trick is to be able to keep a job while doing that. Looks like you've somehow done that with picolisp!

What is an "FTP workflow" in this context. "File Transfer Protocol" doesn't make much sense to me here and I couldn't find anything that would. I'm also at a loss at "hollow dash" TBH.

"Workflow" is a term of art in business software that typically encodes into software what would have been the movement of paper around an office in the past.

In an old paper office, documents would go into people's inboxes for decision making, and would be forwarded to someone else when done. Think of customer service taking a report from a customer (this is the inbox for Customer Support), turning that into an entry in an internal bug database (the inbox for a developer), and then into a code fix up for review (the inbox for a different developer), and so on. This is a workflow. Work literally flows from one person to another throughout the organization.

Where integration between different software systems occurs, there's a spectrum of choices, from humans poking data into UIs through to direct API calls. One of the cheaper automated-yet-ad-hoc integrations is a script which FTPs files into well-known directories, often with semantically significant directory and file name conventions (e.g. dates or company codes). The receiving system polls the FTP location for new data (frequently CSV files), often using regexes or other techniques to extract metadata from filenames (since CSV doesn't really support non-repeating metadata).

So FTP workflows is an ad-hoc workflow integration using FTP to connect two different software systems, replicating what would have been done by paper 20 years ago.

It probably does actually mean "File Transfer Protocol". Its not uncommon (or wasn't at least) to find workflows that rely on data files of a specific format (to varying degrees) being FTP'd into the right server and then processed by that server.

For example, I found this [1] randomly while googling.

1: https://www.ibm.com/docs/en/order-management-sw/9.4.0?topic=...

> "hollow dash"

That's because you never had to attend a uml profile meeting where people discuss the style of arrows.

Think people trying to customize this https://i.stack.imgur.com/YCegU.png with different line patterns for hours

Thanks for trying to answer it. I'm still confused why it should be a "hollow dash". I mean "hollow arrow" would make perfect sense, but dash? Maybe I'm overthinking it;-)

You can discuss what colour they should be too.

You don't think they avoided that topic

> for clueless clients stuck in manual FTP workflows

This kills my soul. UML is being presented as a way to abstract away from the actual processes. But not everything can be abstracted away. The fact that we need to picture a UML diagram to represent a user stuck in FTP is outright a waste of time, money and human labor.

I only ever use sequence diagrams, mostly to put on presentation slides :)

Class diagrams are a waste of time and they go stale quickly. Nobody updates them once the development tempo starts picking up.

Don’t worry. UML is just not very good. I have tried it myself and I also have never seen a decent sized project that was designed successfully with UML. People don’t understand the diagrams and they are hard to iterate on. Working with UML is tedious instead of supporting you.

Problem was and apparently still is: tooling

When you have to sync your UML with your code by hand, it quickly becomes a burden.

But for initial design, I really like UML.

I use it too for first thoughts about the project. It is also a decent reference. But once the project has a "personality" the UML goes away pretty much. And only the complex stuff needs the UML. The simple patterns are complete unto themselves.

Intellij IDEs autogenerate/sync UML. And if you're not on Intellij IDEs you've got a bigger problem

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