21 May
2008
21 May
'08
4:31 p.m.
Hello HP, 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.
impossible because these are different types :)) 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 or shortly combine p1 p2 p3 x = p1 x >>= p2 >>= p3 -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com