[erlang-questions] Fear and Loathing in Programming La La Land
Thu Mar 29 09:49:22 CEST 2012
You're certainly not alone :) The idea of create-set-call is, imho, madness. It means that you never really know if an object is in a sane state to be used - what properties need to be set to make the object "usable"? What happens if some properties are set more than once? What if I set some properties, start using the object, and then change some properties?
I much, much prefer passing arguments to a constructor and knowing that when it returns to me I have an object in a sane state to use. That said, some of the C# objects have way to many overloaded constructors - named parameters no doubt help here, as would better adherence to the SRP.
The level of some of the programmers out there is scary - if it were the medical or legal profession, they'd be struck off - who'd want an 'opportunistic' doctor, who's measure of success was how quickly he could get through patients, with scant disregard to how many of them later end up at the mortuary...
Love the C example :)
-- Steve. Strong
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On Thursday, 29 March 2012 at 09:32, Richard O'Keefe wrote:
> I'm to the Psychology of Programming Interest Group mailing list.
> In a discussion of naming, reference was made to a body of work
> Usability Implications of Requiring Parameters
> in Objects' Constructors
> by Jeffrey Stylos of CMU
> and Steven Clarke of Microsoft
> at http://www.cs.cmu.edu/~NatProg/papers/Stylos2007CreateSetCall.pdf
> The abstract reads
> The usability of APIs is increasingly important to programmer
> productivity. Based on experience with usability studies of
> specific APIs, techniques were explored for studying the usability
> of design choices common to many APIs. A comparative study was
> performed to assess how professional programmers use APIs with
> required parameters in objects’ constructors as opposed to
> parameterless “default” constructors. It was hypothesized that
> required parameters would create more usable and self-documenting
> APIs by guiding programmers toward the correct use of objects and
> preventing errors. However, in the study, it was found that,
> contrary to expectations, programmers strongly preferred and
> were more effective with APIs that did not require constructor
> parameters. Participants’ behavior was analyzed using the
> cognitive dimensions framework, and revealing that required
> constructor parameters interfere with common learning strategies,
> causing undesirable premature commitment.
> The study was done in 2005.
> We're talking about the difference between
> fs = new FileReader("foo/bar.txt", Sharing.NONE);
> ln = fs.ReadLine();
> fs = new FileReader();
> ln = fs.ReadLine();
> I think this is worth bringing up here because if functional programming
> is about anything at all, it's certainly about NOT setting up a value one
> field at a time!
> Their sample was carefully chosen to include three kinds of programmers:
> * OPPORTUNISITC programmers are more concerned with productivity
> than control or understanding. For these programmers objects
> that required constructor parameters were unfamiliar and
> unexpected, and even after repeated exposure these programmers
> had difficulty with these objects.
> That is, they just didn't "get" the idea of constructors having
> * PRAGMATIC programmers balance productivity with control and
> understanding. These programmers also did not expect objects
> with required constructors, and while pragmatic programmers
> were more effective than opportunistic programmers at using
> these objects, the objects still provided a minor stumbling
> block and these programmers preferred the flexibility offered
> by objects that used the create-set-call pattern.
> Remember, this was all about .NET. Failing to expect
> constructors with parameters in C# is like failing to expect
> assignment statements in C.
> * SYSTEMATIC programmers program defensively and these are the
> programmers for whom low-level APIs are targeted. These programmers
> were effective at using all of the objects; however, they preferred
> create-set-call because of the finer granularity of control it
> offered by allowing objects to be initialized one piece at a time.
> The purpose of the study was to provide guidelines for API designers at
> Microsoft: apparently they now recommend create-set-call. Remember,
> that's the idea where you create an object without saying *anything* about
> what you want it to be and then successively kick it into shape.
> They later say
> [Systematic programmers] want not just to get their code working,
> but to understand why it works, what assumptions it makes
> and when it might fail. They are rare, and prefer languages that
> give them the most detailed control such as C++, C and assembly.
> I'd like to think of myself as a systematic programmer. I certainly like
> to understand all those things. But if I preferred assembly I would not
> be writing in the Erlang mailing list! The basic conclusion seems to be
> that you should not design APIs for such rare animals.
> I made what I thought were three obvious points:
> (1) There is a confounding factor in the study: the create-set-call style
> lets you *name* the information going into an object, while at that
> time the full-initialisation style did not. There are constructors
> for System.IO.FileStream with six arguments; maybe more. It seemed at
> least *possible* that if the subjects had been given a third choice,
> constructors with *named* parameters, they might have preferred that.
> Because the study didn't include such a choice, we certainly cannot
> use it to argue *against* that style.
> (2) C# 4.0 has named (and optional) parameters, so the study is no longer
> adequate to tell us about good API design in C#.
> (3) If there are programmers out there who *don't* care much about
> understanding what they are doing, I certainly don't want them writing
> anything that might in any way affect me or anyone I care about.
> If they just don't "get" constructors with parameters, that's really
> A lengthy discussion has followed in which I've felt rather lonely.
> I'm being beaten about the head for not noticing things in the study
> that I did notice, and for being rather elitist. One quote:
> We don’t have the luxury of dismissing these types of programmers.
> While it might strike you with terror that these programmers exist,
> It doesn't frighten me that they _exist_,
> it frightens me that they are _programming_.
> they are successfully building applications in many different domains.
> They may work differently to you and many other programmers but that
> doesn’t necessarily mean that the code they create is worthless.
> Within the Visual Studio team at Microsoft we’ve devoted efforts to
> attempting to make them successful by adapting to their workstyles
> when appropriate.
> I find myself wondering just how "successful" their applications really are.
> Oh no! I hope they're not writing climate modelling code! That would
> explain so much... (Yes, I've looked at the code in the ClimateGate dump.)
> Frankly, I've turned here for a bit of comfort. If anyone likes completely
> initialising things rather than smacking one field at a time, surely I will
> find such people here.
> Am I wrong? Would *you* be happy opening a file in C by doing
> FILE *f = malloc(sizeof f);
> set_title(f, "foo/bar.txt");
> set_access(f, "r");
> gets(f, buffer);
> erlang-questions mailing list
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