Am 12.09.2014 um 11:32 schrieb alex:
> Haskell has been a really great host language for Tidal
> (http://yaxu.org/tidal). I've found Haskell's Applicative type and its
> syntax extremely useful, and ghc's string overloading hack helps with
> tersity.. As I'm entirely self-taught as far as Haskell and FP is
> concerned, I'm wondering if there's something I'm missing.. For
> example I read about arrows and lenses but don't have any grasp of
> what they are.
I can't say much about the competitors lenses and fclabels, but
data-accessor provides a type (Accessor a b), which gives you read and
write(!) access to record fields. In contrast to that, you can use the
plain record field name only for read access. Like you can combine two
field names to nested records e.g. (fieldA . fieldB), you can combine
accessors.
And guess, Accessor is an instance of Category (but not of Arrow,
because 'arr' is missing).
The package also gives a short introduction:
http://hackage.haskell.org/package/data-accessor
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