On 2/12/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
Hello, the "Advanced Monads" page in the Haskell Wikibook (http://en.wikibooks.org/wiki/Haskell/Advanced_monads) contains the following example of a List Monad pythags = do x <- [1..] y <- [x..] z <- [y..] guard (x^2 + y^2 == z^2) return (x, y, z) However, whenever you load that function definition into Hugs or GHCi, you get a message saying that "guard" is an undefined variable. Does anyone know why? Thanks. phiroc
In the context of the tutorial, guard isn't defined until the next section: additive monads.
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