Last login: Wed Feb 27 12:12:15 on ttys009
: ~ ; exec /Users/dmason/fs/Courses/cps506/Lectures/Haskell/ghci.sh
GHCi, version 7.10.3: http://www.haskell.org/ghc/  :? for help
[1 of 1] Compiling March01          ( lecture.hs, interpreted )
Ok, modules loaded: March01.
*March01> let a = 7
*March01> :t a
a :: Num a => a
*March01> let f () = a
*March01> f()
7
*March01> :t f()
f() :: Num a => a
*March01> let f x = a + x
*March01> :t f
f :: Num a => a -> a
*March01> f 5
12
*March01> let a = 37
*March01> f 5
12
*March01> f 3.14
10.14
*March01> let g x y = (x+1,y+1.5)
*March01> :t g
g :: (Fractional t1, Num t) => t -> t1 -> (t, t1)
*March01> let h x y z = [(x y),head z]
*March01> let h x y z = [x y,head z]
*March01> 
*March01> :t h
h :: (t1 -> t) -> t1 -> [t] -> [t]
*March01> let i x y z = map (map x) (y z)
*March01> :t map
map :: (a -> b) -> [a] -> [b]
*March01> :t i
i :: (a -> b) -> (t -> [[a]]) -> t -> [[b]]
*March01> :h
        [ help on the ghci interactive commands ]
*March01> :browse Prelude
        [ a listing of many functions, modules, and type classes ]
*March01> let j x y z = (x<=y,x==z)
*March01> :t j
j :: Ord a => a -> a -> a -> (Bool, Bool)
*March01> let j x y z w = (x<=y,w==z)
*March01> :t j
j :: (Eq a1, Ord a) => a -> a -> a1 -> a1 -> (Bool, Bool)
*March01> let f x y = x - y
*March01> :e
[1 of 1] Compiling March01          ( lecture.hs, interpreted )
Ok, modules loaded: March01.
*March01> :t f

<interactive>:1:1: Not in scope: ‘f’
*March01> let f x y = x - y
*March01> let l = [1,2,3,4]
*March01> :t map f l
map f l :: Num a => [a -> a]
*March01> let g x f = f x
*March01> length (map f l)
4
*March01> map (g 4) (map f l)
[-3,-2,-1,0]
*March01> map (g 45) (map f l)
[-44,-43,-42,-41]
*March01> map (g 45) (map f [3,4,5])
[-42,-41,-40]
*March01> :t (+)
(+) :: Num a => a -> a -> a
*March01> map (3+) [1,2,3]
[4,5,6]
*March01> :info (+)
class Num a where
  (+) :: a -> a -> a
  ...
  	-- Defined in ‘GHC.Num’
infixl 6 +
*March01> 3`f`4
-1
*March01> let second x = head (tail x)
*March01> second [4,5,6]
5
*March01> let second x = head $ tail x
*March01> second [4,5,6]
5
*March01> :info ($)
($) :: (a -> b) -> a -> b 	-- Defined in ‘GHC.Base’
infixr 0 $
*March01> :info (.)
(.) :: (b -> c) -> (a -> b) -> a -> c 	-- Defined in ‘GHC.Base’
infixr 9 .
*March01> let d f g x = g(f(x))
*March01> :t d
d :: (t2 -> t1) -> (t1 -> t) -> t2 -> t
*March01> let d f g x = f(g(x))
*March01> :t d
d :: (t1 -> t) -> (t2 -> t1) -> t2 -> t
*March01> let second = head . tail
*March01> second [4,5,6]
5
*March01> map (g 4) . map f $ l
[-3,-2,-1,0]
*March01> map ($ 4) . map f $ l
[-3,-2,-1,0]
*March01> let third x = head ( tail (tail x))
*March01> let third x = head $ tail $ tail x
*March01> map third ["asdf", "qwer", "zxcvvv"]
"dec"
*March01> map (\x -> head $ tail $ tail x) ["asdf", "qwer", "zxcvvv"]
"dec"
*March01> map (head . tail . tail) ["asdf", "qwer", "zxcvvv"]
"dec"
*March01>