On 25 April 2011 14:11, Angel de Vicente
OK, I have tried it and it works, but I don't understand the syntax for curry. Until now I have encountered only functions that take the same number of arguments as the function definition or less (partial application), but this syntax looks a bit new to me. curry is supposed to have as its argument one function of type (a,b) -> c and produce another function, but then the second line gives three arguments to curry, the function itself and the variables x and y.
What I'm missing here?
You can think of all functions in Haskell as taking only one argument. So curry has one argument, which is a function that takes a pair (in this case g). The value of curry g is another function (the curried version of g) which takes two arguments. This is clearer when written out like so: g :: (a, b) -> c h :: a -> b -> c h = curry g h x y = g (x, y) So by simple substitution we can see that curry g x y = g (x, y) It might be even clearer if we add parentheses, since function application associates to the left: (curry g) x y = g (x, y) Hope this clears things up. For more information you could have a look at the Gentle Introduction's section on functions: http://www.haskell.org/tutorial/functions.html Benedict.