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A comment on “Mostly functional” programming does not work (2014). Parent comment

Re:“Mostly functional” programming does not work (2014) by kstenerud on Monday June 22, 2015 @11:27AM (#9758951)
Exactly right. While some purists will bemoan imperfection and invent all sorts of "horror stories" from their ivory tower, engineers who actually get things done are quite satisfied with "good enough." Functional purism after awhile starts to smack of the bad old days of waterfall development, where each step in the series requires perfection lest the remaining steps collapse (if everyone would just follow this perfect system, we'd all have rainbows and unicorns).

You can have perfect safety, or you can have a workable system delivered in a timely manner.

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Re:“Mostly functional” programming does not work (2014) by sacado2 on Monday June 22, 2015 @01:23PM (#9759779)
Well, sometimes perfect safety is the only option. Would you fly on a plane that is piloted by a workable system delivered in a timely manner ?
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Re:“Mostly functional” programming does not work (2014) by bunderbunder on Monday June 22, 2015 @03:19PM (#9760589)
Considering the languages that are normally used to write aircraft control software, this is perhaps a questionable choice of example.

And there are probably very good reasons why a language like Haskell is not likely to be chosen for this kind of application. Consider predictability: Haskell may make it easy to prove algorithmic correctness, but its laziness makes runtime characteristics more difficult to reason about because they're hidden behind so much abstraction. This could make it very difficult to deal with stuff like subtle bugs related to timing issues that might crop up in an electromechanical system.

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Re:“Mostly functional” programming does not work (2014) by sacado2 on Tuesday June 23, 2015 @10:21AM (#9764779)
Yes, I totally agree, I was just questioning the above assertion : "perfect safety is only good for ivory tower guys".
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Re:“Mostly functional” programming does not work (2014) by coldtea on Monday June 22, 2015 @06:15PM (#9761558)
Perfectly safe systems like planes, missiles, space missions etc. are 99% done in imperative languages such as C and Ada.

Not Haskell and not even Lisp.

The last thing you want from a perfectly safe system is some lazyness smartness in the compiler hitting at the wrong time and affecting execution time, memory use etc, or things like GC pauses.

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Re:“Mostly functional” programming does not work (2014) by sacado2 on Tuesday June 23, 2015 @10:22AM (#9764788)
Yes. My comment was not clear, I don't associate "perfect safety" with functional purity. Quite the opposite actually, for the reasons you gave.
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Re:“Mostly functional” programming does not work (2014) by dagw on Thursday June 25, 2015 @06:31AM (#9776953)
Would you fly on a plane that is piloted by a workable system delivered in a timely manner ?

I do every time I get in a plane.

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