Haskell notes

Haskell is a purely functional programming language. (That is, functional as opposed to imperative/procedural programming languages. C, Java, and Perl are imperative languages. Lisp, Scheme, Ocaml, and Erlang are functional languages.) Haskell is different from any language I've used before; it reminds me a bit of SQL.

The most popular Haskell implementation is GHC (Glasgow Haskell Compiler), which has three components:

ghc
a Haskell compiler which generates a native binary
ghci
an interactive interpreter and debugger
runghc
run Haskell code as a script, without compiling it
{----------------------------------------------------------------------------
    Comments
----------------------------------------------------------------------------}

-- This is a single line comment.
{- This is...
...a multi-line...
...comment -}

{----------------------------------------------------------------------------
    Arithmetic
----------------------------------------------------------------------------}
2 + 2       -- Infix addition
(+) 2 2     -- Prefix addition; operator must be in parens
2 * (-3)    -- Negative numbers need to be in parens to avoid ambiguity

{----------------------------------------------------------------------------
    Functions
----------------------------------------------------------------------------}

-- Optional type signature declared before type definition:
thingy :: Int -> Int -> Int
-- A function definition:
thingy x y z = x * ( y - z )

-- Guards make choices in functions based on boolean expressions:
max :: Ord a => a -> a -> a
max x y
    | x > y = x
    | otherwise = y

{----------------------------------------------------------------------------
----------------------------------------------------------------------------}

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