PipalMask.mesa 
Copyright Ó 1988 by Xerox Corporation. All rights reserved.
Louis Monier January 15, 1988 9:44:22 pm PST
Bertrand Serlet March 7, 1988 3:55:30 pm PST
DIRECTORY Pipal, PipalInt, PipalPaint;
PipalMask: CEDAR DEFINITIONS = BEGIN
Theory
Geometry and color: the Pipal data structures which will some day turn to silicon.
Layers
Layer: TYPE = PipalPaint.Color; -- enough for now
Basic Classes
Brick
brickClass: Pipal.Class;
Brick: TYPE = REF BrickRec;
BrickRec: TYPE = RECORD [
size: PipalInt.Size,
layer: Layer];
CreateBrick: PROC [size: PipalInt.Size, layer: Layer] RETURNS [brick: Brick];
It is not legal for a brick to be reduced to a line or a point
END.