[Haskell-cafe] What Haskell Records Need

[Richard O'Keefe]

On 2/08/2012, at 5:34 PM, Jonathan Geddes wrote:
> Ouch! And that's not even very deeply nested.
> Imagine 4 or 5 levels deep. It really makes
> Haskell feel clunky next to `a.b.c.d = val`
> that you see in other languages.

I was taught that this kind of thing violates the Law of Demeter
and that an object should not be mutating the parts of an
acquaintance's parts, but should ask the acquaintance to do so.
I'd say that a.b.c.d = val is at the very least a sign that
some encapsulation did not happen.

Semantic editor combinators are ingenious, but they make
me feel somewhat uneasy, in that they really are in some
sense about the *syntax* (or maybe the concrete representation)
of things rather than their *semantics* (or maybe I mean the
abstract value).