[Haskell-cafe] New slogan for haskell.org

Henning Thielemann lemming at henning-thielemann.de
Mon Oct 8 16:52:01 EDT 2007

On Mon, 8 Oct 2007, Alistair Bayley wrote:

> On 08/10/2007, Henning Thielemann <lemming at henning-thielemann.de> wrote:
>> You cannot turn any programmer into a disciplined programmer just by
>> giving him a well designed language. I you try so, they will not like to
>> use that language, will leave that language as soon as possible or they
>> try to adapt the language to their style of programming.
> Well, I wasn't suggesting you'll create great programmers overnight,
> but you might expect that their appreciation of good design might
> improve after some Haskell exposure. Also, Haskell simply doesn't
> support some of the things that are common causes of errors in the
> enterprisey-language world. I recall reading something about one of
> the most common causes of errors in novice programs being type errors
> (presumably, once they'd got the program to compile i.e. there were no
> syntactic errors). And I'm under the (possibly mistaken) impression
> that some of the common errors non-novice programmers make are
> aliasing bugs, and/or use of global variables. Does anyone have
> references to studies confirming (or refuting) this?

Thus, what happens today? People ask Haskell-Cafe how to implement global 
variables and they are advised to use IORefs and unsafePerformIO, although 
the better answer is: "Why do you want to do this?" Even "Tackling the 
awkward squad" considers unsafePerformIO an acceptable tool for handling 
global configuration files.

>> People who are used to weak typing will use a type like
>>    data Number = Int Int | Float Float | ...
>>   for numbers, or even String for everything, they will use numbers, where
>> enumerations are more appropriate and so on.
> I think that the ease with which you can create a new type in Haskell
> (and derive useful classes like Enum, Show, etc) makes it more likely
> that a programmer will use an appropriate domain-specific type, rather
> than just reuse String, Int, or Float.

I know of popular Haskell libraries which ignore disciplined type design, 
but I do not want to hurt their authors ...

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