On Dec 15, 2011, at 4:29 PM, Chris Wong wrote:
>> Okay, so how about the following as a user narrative for some and many?
>>
>> ...
>
> I was in the middle of writing my own version of Applicative when I
> stumbled on this intense debate. Here's what I wrote for the
> documentation:
>
> class (Applicative f, Monoid f) => Alternative f where
> -- | Keep repeating the action (consuming its values) until it
> fails, and then return the values consumed.
> --
> -- [Warning]: This is only defined for actions that eventually fail
> -- after being performed repeatedly, such as parsing. For pure values such
> -- as 'Maybe', this will cause an infinite loop.
> some :: f a -> f [a]
> some v = ...
>
> -- | Similar to 'many', but if no values are consumed it returns
> 'empty' instead of @f []@.
> --
> -- [Warning]: This is only defined for actions that eventually fail
> -- after being performed repeatedly, such as parsing. For pure values such
> -- as 'Maybe', this will cause an infinite loop.
> many :: f a -> f [a]
> many v = ...
>
> Warnings are repeated for emphasis :)
I think that merely putting up documentation along these lines would be a huge
improvement, though it should also contain the formal definitions from the old
documentation in it somewhere as well.
Cheers,
Greg
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