{- Haskel example code for CMSC 631 presentation
   by Kevin Atkinson and John Simmons -}

-- *** SLIDE 6 ***
-- lazy evaluation: this is legal to type, but not to evaluate
s6_1 = 1/0

-- *** SLIDE 8 ***
-- type inference
s8_1 = 5+3.0		-- s81 gets 8.0
-- some pre-defined types
s8_2::Integer
s8_2 = 1
s8_3::Char
s8_3 = 'A'
s8_4::String
s8_4 = "Foo"
s8_5::Float
s8_5 = 1.0
-- a polymorphic type
s8_6 :: a -> [a]
s8_6(x) = x:[]

-- *** SLIDE 9 ***
-- some user-defined types
type S9_1 = String
data S9_2 = Red|Green|Blue
type S9_3 = [Integer]		-- an int list
s9_3::S9_3
s9_3 = [1,2,3,4,5]
type S9_4 = (Float,Float)	-- a tuple
s9_4::S9_4
s9_4 = (1.0,2.0)
data S9_5 = MyRecord {first::Integer,second::Float} -- a record
s9_5::S9_5
s9_5 = MyRecord {first = 9, second = 4.5}
-- a type class
class MyClass a where
  foo :: a -> Integer
-- a subclass
class (MyClass b) => MySubClass b where
  bar :: b -> String
-- an instance
instance MyClass Integer where
  foo x = x::Integer

-- *** SLIDE 10 ***
data RealFloat a => Complex a = !a :+ !a

-- *** SLIDE 11 ***
s11_1 = 1:s11_1  -- an infinite list of 1's