Is there a software-engineering methodology for functional programming?

Re:Is there a software-engineering methodology for functiona... by Dn_Ab on Sunday February 06, 2011 @12:52PM (#2186035)

I see what you mean. It makes a lot of sense. Its just that I take a dual approach in looking at it. You can look at simple diagrams as subsets of UML as I think you do? But personally, I would say that simple effective diagrams are a superset of UML. You get UML when you take simple diagrams and add bombastic restrictions.

Its a matter of perspective and I can't say which makes more sense.

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Re:Is there a software-engineering methodology for functiona... by DanielBMarkham on Sunday February 06, 2011 @01:19PM (#2186091)

There's a fun little book called "Back of the Napkin" (warning: affiliate link ahead) http://amzn.to/ezUvgk

In it, the author develops his own little modeling system and talks about how to use it. While he goes a bit overboard (must be something in the water) his point is an excellent one: visual modeling conveys information at a bandwidth of an order or two of magnitude above conversations or documents.

I recently had a functional project. It was a greenfield project and had a MySql backend. I wanted to use dynamic data in some parts and relational in others, fully taking advantage of both FP and the relational model.

Problem was, I wasn't sure exactly how I wanted each piece to work. So, I picked up some scrap paper, a pencil, and sketched out some ideas.

They sucked.

A couple of days later I did it again. This time I saw some things I had been missing.

It also sucked.

A day after that, I sat down and sketched out what I wanted. Finally.

It didn't suck.

This entire process took a total of maybe 2 hours spread out over three days. A pencil and scrap paper. Soemtimes I just drew boxes with labels in them, sometimes I added aggregation or composition, sometimes I put in navigation. If I had continued to be stuck, I might have used a sequence diagram, or a collaboration diagram, or any one of a hundred other tools in my UML toolbox.

The point is: I never sat down and told myself "I'm going to be doing UML right now. I didn't get out some big fancy tool, and I didn't make something that looked like the wiring diagram for a nuclear device. That's not how it works. It's a spectrum. Some of my diagrams might have looked like an ER diagram, or just a bunch of junk on paper. Doesn't matter. The process of diagramming served it's purpose of organizing and capturing my thoughts about how the system would be structured. When I needed more complexity, I reached into my UML toolkit and added new complexity. If I didn't need it, I didn't use it. UML worked for me. I didn't work for it.

So I don't see UML as even being the same kind of thing as some of the other folks. There's no dual nature at all -- it's just a technical way of drawing pictures. And who doesn't need a picture now and then?

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