CompareFunc
typealias CompareFunc = (<Error class: unknown class>?, <Error class: unknown class>?) -> <Error class: unknown class>
Specifies the type of a comparison function used to compare two values. The function should return a negative integer if the first value comes before the second, 0 if they are equal, or a positive integer if the first value comes after the second.
param
a
a valueparam
b
a value to compare withreturn negative value if @a < @b; zero if @a = @b; positive value if @a @b