2007/12/28, Alfonso Acosta <[EMAIL PROTECTED]>: > @ works as an aliasing primitive for the arguments of a function > > f x@(Just y) = ... > > using "x" in the body of f is equivalent to use "Just y". Perhaps in > this case is not really useful, but in some other cases it saves the > effort and space of retyping really long expressions. And what is even > more important, in case an error is made when choosing the pattern, > you only have to correct it in one place. >
And in plenty of case it will greatly boost your speed because you won't be reconstructing the objects against which you matched every time you want to return them unchanged. -- Jedaï _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
