Comment by corethree
2 years ago
>Software design, in my opinion, is both a science and an art so my stance is that we need both the formal theory and science as well as the philosophy and that they shouldn't be viewed as mutually exclusive.
What formal theory have you ever used for designing your software? I would argue you've never used anything. Every abstraction you've ever made was likely a gut feeling, an instinct or following some vague hand wavy rule of thumb.
At best we use type theory for type correctness and complexity theory to calculate efficiency. That's basically as far as it goes with "theory" and these two things aren't even about "software design".
Software design in practice as most engineers use it today is, practically speaking (key phrase), 100% art. Sometimes people come up with big fancy words like "dependency injection" or stupid Acronyms like SOLID to create the illusion of formal theory, but these things are nothing of the sort. It's just tips and tricks.
The plane, the car, the bridge? Those things use both design and formal theory... software design as most engineers use it, again, does not use ANY formal theory, it's almost just purely design all the way down.
Aren't you being overly optimistic about the engineering disciplines' ability to compute things? How does engineering work: do you sit down with a spec (say, "create a wing that can lift a passenger plane"), and then run some formulas, and end up with a wing? Or do you propose a wing, based on past experience (rough shape and size), and _then_ bring in computation to make sure it provides the correct amount of lift, iterating through designs as you go?
Because I think it's really the last one. There is no formula to design a bridge: you design the bridge, and then use formulas and lookup tables to validate it is strong enough. Same for pretty much anything else produced by any engineering discipline.
So in that sense, engineering and programming aren't all that far apart: both start from past experience, and use various validation methods after a design has been proposed, iterating through designs to reach an optimal state. Software engineering, being a younger discipline, is still working on validation methods, and many practitioners find they simply have no budget to apply them (nor any life-or-death constraints that force them to). That's ok though. If you design a new can opener you aren't going through all the processes that apply to an airliner either.
No. theory is very much part of the creation of the bridge. It is not just for verification.
If you read more carefully. What I am saying is that in software engineering, there is no theory. It's all Design. All made up. There's also no verification of the design itself.
> There's no verification of the design itself.
I think this is mostly a philosophical statement, but it certainly has truth to it.
Code reviews / rework tackle mostly the code, but not the fundamental design. However the execution of the code tackles the design as well:
- If the design is wrong, the result is bad, that is detected at the execution phase.
- If the design is suboptimal (hard to maintain or extend, bad cpu load, hard to reuse...), well that is usually not solved. IMO that matches your point.
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Just because it doesn't use formal theory now --- does not mean it/we shouldn't use it. I'm talking about needs, not haves.
Well in all other engineering fields although they are used in conjunction. The two concepts are practically more or less mutually exclusive. There's no room for "design" when finding the shortest distance between two points because the shortest distance between two points is done via calculation using formal theory.
Things like user-friendliness can be "philosophical". You can separately and selectively apply theory and design where applicable, but they cannot in actuality be unionized in some unholy grafting.
I would say for the topic at hand; Of how to organize and abstract your code, if we ever find a complete formal theory for that, much of design will go out the window and what's left is mostly a calculation.
I see what you are driving at and I think we are looking at the problem from slightly different lenses yet still drawing much the same conclusions.
There's no room for design in finding the shortest distance between two points, but there is room for design in picking which points you wish to find the distance on -- I think perhaps for meaningful discussion on this specific topic my definition of "Software Design" is too broad-scope ;)
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