Re: [Haskell-beginners] Functions as Applicatives

What exactly is f x (g x)? is it (f x)(g x)?? ... Looks like two numbers to me e.g. 42 43 ... This can only make sense if they are arguments to another binary function which I don't see. Or is there something I'm missing? - Olumide On 22/08/16 22:14, Rein Henrichs wrote:

In f <*> g = \x -> f x (g x), g is the second argument to <*>. The result of f <*> g is a function that takes an argument (x) and gives f x (g x). So basically <*> combines the functions f and g in a particular way to give a new function. In fact, it is the only way to combine them that type checks (and doesn't use undefined or similar).

On Mon, Aug 22, 2016 at 11:13 AM Imants Cekusins mailto:imantc@gmail.com> wrote:

.. actually, I got fg wrong. Caught it by changing g to (/ ):

f::Fractional f => f -> f -> f f = (+)

g::Fractional g => g -> g g a = a / 2

h::Fractional h => h -> h h = (* 10)

fg::Fractional a => a -> a -> a fg = f <$> g {- fg a b = (a / 2) + b fg a = \b -> (a / 2) + b -}

fgh::Fractional a => a -> a fgh = fg <*> h {- fgh a = fg a (a * 10) fgh = \a -> fg a (a * 10) -}

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