SCHEMA example_schema;

TYPE label = STRING;

END_TYPE;

TYPE color = ENUMERATION OF (red, green, blue, yellow, orange, white, black, brown);

END_TYPE;

TYPE length_measure = REAL;

END_TYPE;

TYPE point = REAL;

END_TYPE;

ENTITY shape

SUPERTYPE OF (ONEOF (circle, triangle, rectangle));

item_name : label;

item_color : OPTIONAL color;

number_of_sides : INTEGER;

END_ENTITY;

ENTITY circle

SUBTYPE OF (shape);

radius : real;

END_ENTITY;

ENTITY triangle

SUBTYPE OF (shape);

side1_length, side2_length, side3_length : length_measure;

END_ENTITY;

ENTITY rectangle

SUPERTYPE OF (square)

SUBTYPE OF (shape);

height : length_measure;

width : length_measure;

END_ENTITY;

ENTITY square

SUBTYPE OF (rectangle);

END_ENTITY;

ENTITY cartesian_point;

x : point;

y : point;

z : OPTIONAL point;

END_ENTITY;

ENTITY line;

end_point_one : cartesian_point;

end_point_two : cartesian_point;

END_ENTITY;

ENTITY poly_line;

points : LIST OF line;

END_ENTITY;

END_SCHEMA;