Copy deeply copies a slice of elements that each, in turn, must be copied using their own Copy method.

Filter applies function "f : X => bool" to each value X of the input slice, and returns a new slice containing only each X for which f(X) is true.

FlatMap applies function "f : X => []Y" to each value of the input slice, and returns a new slice of each output in sequence.

ForEach applies the void function "f(x)" to each value X of the input slice.

FromArgs returns the slice of the variadic arguments list.

Map applies function "f : X => Y" to each value of the input slice, and returns a new slice of each output in sequence.

Reduce applies function f to each element of the slice (in increasing order of element index) with the previous return value from f as the first argument and the element as the second argument (for the first call to f, the supplied initial value is used instead of a return value), returning the final value returned by f.

Reducer constructs a partially-applied Reduce function with the arguments "initial" and "f" already bound.