21 May
2008
21 May
'08
4:55 p.m.
On 2008 May 21, at 12:31, Bulat Ziganshin wrote:
Wednesday, May 21, 2008, 8:11:56 PM, you wrote:
Suppose p1, p2, p3 are 3 predicates that take an input -- say, a String. They return either (True, result) or False.
if they return Just result or Nothing - yes, use Maybe as monad:
combine p1 p2 p3 x= do x1 <- p1 x x2 <- p2 x1 x3 <- p3 x2 return x3
S/He's not passing on r (the result), but s (the argument). Monad ((-
) r)?
-- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH