10 Feb
2008
10 Feb
'08
10:59 a.m.
On Sun, 10 Feb 2008, Luke Palmer wrote:
Quite frequently.
Here are a few examples from my own code:
For "functional references" (representing a bidirectional function from a data type to a part of itself (for example the first element of a pair)).
data Accessor s a = Accessor { get :: s -> a , set :: a -> s -> s }
My quantum computation arrow (really in the realm of "concrete, useful things", huh? :-)
The pattern seems to be common enough to be turned into a package. http://www.haskell.org/haskellwiki/?title=Record_access&action=history