--head [1,2,3,4]
-- vraca glavu liste
--tail [1,2,3,4]
--vraca rep liste 

--f-ja se definise
-- naziv_fje arg1 arg2 arg3... = {telo funkcije}

double x = x+x
doublesum x y = x*x + y*y 

--double je tipa Int->Int
--prilikom poziva "take double 2 [1,2,3,4,5]"
--koji tip prihvata take?
--Int->Int->Int->[a]

--pravilno je " take (double 2) [1,2,3,4,5]"

somefunc x y = 3*y2 + x*y2
	where 
		y2 = y*y

xs1 = [1,2,3,4,5]

last1 xs = xs !! (length xs - 1)
last2 xs = head (reverse xs)	

init1 xs = take (length xs -1) xs
init2 xs = reverse (drop 1 (reverse xs))

--provera tipova
--Main> :type True
--True :: Bool
--Main> :type 4
--4 :: Num a => a
--Main> :type 4.5
--4.5 :: Fractional a => a
--Main> :type pi
--pi :: Floating a => a
--Main> :type xs1
--xs1 :: [Integer]


--[("Marko",9.8),("Ivana", 9.7)]

scalarm :: (Int,Int,Int)->(Int,Int,Int)->Int
scalarm (x1,y1,z1) (x2,y2,z2) = x1*x2+y1*y2+z1*z2

--currying

--Main> (scalarm (1,2,3)) (4,5,6)
--32
--Main> map (scalarm (1,2,3)) [(2,3,4),(5,6,7)]
--[20,38]