Set
This module provides functions for manipulating Sets. Sets are immutable data structure containing unique elements.
Usage¶
There is function Set::empty to create a new empty set. Sets support special operators for adding elements or operations typical for sets, such as unions or intersections etc.
Folding a set¶
Folding a set is a process of iterating over its values while producing one result value. An example of a folding function could be a sum function, that iterates over all elements and adds them up, producing a single result.
Functions foldl take 3 arguments: * 2-argument lambda (accumulator, element) returning a new value of an accumulator * initial value of the accumulator * set to fold
This example shows how to sum up a set:
Set::fold (\acc val -> acc + val) 0 {1, 2, 3}
Reducing a set¶
Reducing a set means applying a transducer onto a set. Transducers are a generic, high-level method for implementing operations over a data structure.
Function reduce takes 2 arguments: * transducer * set to reduce
Example with a filter transducer:
Set::reduce (Transducers::filter \val -> val < 0 (0, \state val -> state + val, \state -> state * 2)) {-2,-1,0,1,2}
This example will produce -6, as it sums up all negative numbers in the set.
Obtaining a length of a set¶
Function len returns a length of a set:
length = Set::len {1, 2, 3}
Turning a set to a sequence¶
Function to_seq constructs a sequence containing elemtents of the given set. Elements in this sequence are in no particular order.
Example:
Set::to_seq {1, 2, 3}
Will return [1, 2, 3].