The + function returns the sum of its arguments. Each of its arguments should be a numeric expression. Addition is performed using the type of the arguments provided unless mixed mode arguments (integer and float) are used. In this case, the function return value and integer arguments are converted to floats after the first float argument has been encountered. This function returns a float if any of its arguments is a float, otherwise it returns an integer.
Syntax
(+ <numeric-expression> <numeric-expression>+)
Example
CLIPS> (+ 2 3 4) 9 CLIPS> (+ 2 3.0 5) 10.0 CLIPS> (+ 3.1 4.7) 7.8 CLIPS>