[P] Programming

line.class contains the following member programs:
class — Class programming 27
.set program to set .c0 and .c1
.c0.set program to set .c0
.c1.set program to set .c1
.length program to return length of line
.midpoint program to return coordinate of midpoint of line
.set, .length, and .midpoint came from line.class. .c0.set and .c1.set came from
coordinate.class.
Member program .length returns the length of the line.
.len = .li.length
would create .len containing the result of .li.length. The result of running the program .length
on the object .li. .length returns a double, and therefore, .len will be a double.
.midpoint returns the midpoint of a line.
.mid = .li.midpoint
would create .mid containing the result of .li.midpoint, the result of running the program
.midpoint on the object .li. .midpoint returns a coordinate, and therefore, .mid will be a
coordinate.
2. Definitions
2.1 Class definition
Class classname is defined in file classname.class. The definition does not create any instances
of the class.
The classname.class file has three parts:
version . . . // Part 1: version statement
class classname { // Part 2: declaration of member variables
. . .
}
program . . . // Part 3: code for member programs
. . .
end
program . . .
. . .
end
. . .
2.2 Class instance
To create a “variable” name of type classname, you type
.name = .classname.new
begin classname.class
end classname.class