-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 7/13/10 11:20 , Tim Cowlishaw wrote:
actually, looking at it again, it'd be something like
maybeMonoid :: (Monoid a) => Maybe a -> Maybe a -> a maybeMonoid :: x y = (fromMaybe mempty x) `mappend` (fromMaybe mempty y)
Which in turn can be written as:
maybeMonoid = mappend `on` (fromMaybe mempty)
("on" is in Data.Function: "g `on` f" expresses the "\x y -> (f x) `g` (f y)" idiom.) - -- brandon s. allbery [linux,solaris,freebsd,perl] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkw8rE8ACgkQIn7hlCsL25XrugCdFLhDalZflo2P8h4XkdCODqAw tcEAn0siZ8CK0+NKay0dz991kBxkvEjh =Actk -----END PGP SIGNATURE-----