Ref List

Key Ref List in Is Member Of refers to the 1D-array of values that define the reference set.

For example, assume an array with the three elements 4, 7 and 12.
By default, these elements will be interpreted as integers, except if the entry Ref Types specifies otherwise.
Assume the current predicate function is called in a context where one integer variable x is supplied as input.
Then the output of the called predicate function will be TRUE only if x happens to equal any one of these three values.
So, the output would be TRUE if x = 7, but would be FALSE if x = 2.