Good Haskell Style

[Thomas Schilling]

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On 1 aug 2007, at 16.50, Simon Marlow wrote:
> > * Use the CamelCase variable naming convention
>
> I'm rather attached to the convention I use, which is
>
>   - CamelCase for exported identifiers
>   - underscores otherwise
>
> (I'm pretty sure I don't use it consistently, so don't bother to  
> dig up counter-examples though).
>
> Why do I like this?  Ideally we'd have an IDE which would colour my  
> exported identifiers differently, but since I don't use such an IDE  
> the CamelCase distinction gets some of the benefit.  CamelCase for  
> exported identifiers is already an established convention (which  
> should really be part of a library API style guide), which leaves  
> us with underscores for local identifiers.
>
> Yes I'm aware that a single-word identifier is the same in both  
> conventions; it's not perfect.

I don't like that convention.  It makes the code look really ugly.  I  
agree, that it'd be a good idea to have a visual indication what is  
exported and what is not, but i'd strongly opt for something less  
obtrusive.  In any case, though, this is something this should be  
done consistently or not at all; maybe we need some sort of haskell- 
lint?

So, if leading underscores are used already, what about trailing  
underscores?

myPublicFunction :: Foo -> Bar -> Baz
myPublicFunction f b = myInternalHelperFn_ (helper_ f b)

versus

yPublicFunction :: Foo -> Bar -> Baz
myPublicFunction f b = my_internal_helper_fn (helper f b)

it's also much easier to fix when actually exporting the identifier.

Just my 2 cents

/ Thomas
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