files/practicum/Figure.dcl

   1 definition module Figure
   2
   3 /** Example library to demonstrate the use of Existential Types.
   4     The library implements a simple set of drawing objects.
   5
   6     Author:  Peter Achten
   7     Version: April 14 2008
   8 */
   9 import StdPicture
  10
  11 ::  Figure
  12
  13 //  drawFigure f creates a window in which f is displayed
  14 drawFigure      ::          Figure -> *World -> *World
  15
  16 //  convenient lifting operations on the methods of a figure to the figure self
  17 move            :: Vector2  Figure -> Figure
  18
  19 //  Specialized Figure constructor functions:
  20 //  mkFigures figs combines all figs in left-to-right order
  21 mkFigures       :: [Figure]      -> Figure
  22
  23 //  line a b draws a line from a to b
  24 line            :: Point2 Point2 -> Figure
  25
  26 //  rectangle a b forms a rectangle with diagonal-points a and b
  27 rectangle       :: Point2 Point2 -> Figure
  28
  29 //  ellips a b forms an ellips that fits in the rectangle with diagonal-points a and b
  30 ellips          :: Point2 Point2 -> Figure
  31
  32 //  text t a shows a text t with left-top corner at a
  33 text            :: String Point2 -> Figure