ColdC: Function/Method Reference: setadd()

LIST setadd(LIST list, ANY value)

This function appends value to list if it is not already in the list, and returns the result.

Example:

setadd([2, 3, 4], 'foo) 
=> [2, 3, 4, 'foo]
setadd([2, 3, 4], 3)
=> [2, 3, 4]