Operators that can contain expressions sometimes also take arguments.
The BODY operator is one of this type. In this template, it
takes an argument specifying the page background color:
This template generates a page like the
previous one, except that the background color is bright yellow.
TITLE "A Colorful Greeting"
BODY background-color COLOR red 255
TEXT "Yellow world!"
The COLOR operator takes three arguments representing the red, green,
and blue components of a color as numbers between 0 and 255 inclusive.
(This convention, known as RGB format, will be familiar to graphic