###########################################################

  FirstLiterate.lhs

  Simon Thompson, June 1998

  The purpose of this script is 
    - to illustrate some simple definitions 
      over integers (Int);
    - to give a first example of a literate script.

###########################################################


The value size is an integer (Int), defined to be the sum of 
twelve and thirteen.

>       size :: Int
>       size = 12+13

The function to square an integer.

>       square :: Int -> Int
>       square n = n*n

The function to double an integer.

>       double :: Int -> Int
>       double n = 2*n

An example using double, square and size.

>       example :: Int
>       example = double (size - square (2+2))