Passing Parameters to Functions
A better way to convey information from one function to another is to pass parameters
to the called function. Design the function so it expects to receive a number of values.
Remember the Degrees-Radians function? This function is passed a parameter named numberOfDegrees:
(defun Degrees-Radians (numberOfDegrees) (* pi (/ numberOfDegrees 180.0)))
When you call the function, it expects you to pass it a number. The number within
Degrees-Radians is declared as the parameter named numberOfDegrees. For example:
(degrees-radians 90) 1.5708
In this case, the number 90 is assigned to the parameter numberOfDegrees.
You can also pass a variable to a function. For example, you might have a variable
called aDegreeValue that contains the number 90. The following commands set aDegreeValue and pass the variable to Degrees-Radians:
(setq aDegreeValue 90) 90 (degrees-radians aDegreeValue) 1.5708