On 07/20/2013 12:58 AM, Matt Ford wrote:
Hi,
Thanks for the help.
I thought >>= was left associative? It seems to be in the examples from Learn You A Haskell. ...
Yes, >>= is left-associative. The associativity of >>= is not relevant for your example because no two >>= operations actually occur next to each other. The second >>= is part of the lambda occurring as the second argument to the first >>=. Lambdas bind 'the rest of the expression'. [1,2] >>= \n -> [3,4] >>= \m -> return (n,m) is equivalent to: let a = [1,2] b = (\n -> [3,4] >>= \m -> return (n,m)) in a >>= b
I tried to use the associative law to bracket from the right but it didn't like that either...
[1,2] >>= (\x -> (\n -> [3,4])) x >>= \m -> return (n,m))
Any thoughts? ...
Where does that 'x' come from?