set

The set module provides functions for working with Set[A] collections of unique values. It is auto-imported — no import statement needed.

Function Reference

Construction

Function	Signature	Description
new	() -> Set[A]	Create an empty set
from_list	(List[A]) -> Set[A]	Create set from list

Access

Function	Signature	Description
contains	(Set[A], A) -> Bool	Check membership
len	(Set[A]) -> Int	Number of elements
is_empty	(Set[A]) -> Bool	Empty check
to_list	(Set[A]) -> List[A]	Convert to list

Modification (immutable)

Function	Signature	Description
insert	(Set[A], A) -> Set[A]	Add value (returns new set)
remove	(Set[A], A) -> Set[A]	Remove value (returns new set)

Set Operations

Function	Signature	Description
union	(Set[A], Set[A]) -> Set[A]	Union of two sets
intersection	(Set[A], Set[A]) -> Set[A]	Intersection
difference	(Set[A], Set[A]) -> Set[A]	Elements in a not in b
symmetric_difference	(Set[A], Set[A]) -> Set[A]	Elements in either but not both
is_subset	(Set[A], Set[A]) -> Bool	Check if a is subset of b
is_disjoint	(Set[A], Set[A]) -> Bool	Check if no common elements

Higher-Order

Function	Signature	Description
filter	(Set[A], Fn[A] -> Bool) -> Set[A]	Keep matching elements
map	(Set[A], Fn[A] -> B) -> Set[B]	Transform elements
fold	(Set[A], B, Fn[B, A] -> B) -> B	Accumulate over elements
each	(Set[A], Fn[A] -> Unit) -> Unit	Side effect per element
any	(Set[A], Fn[A] -> Bool) -> Bool	Any element matches
all	(Set[A], Fn[A] -> Bool) -> Bool	All elements match

Examples

let a = set.from_list([1, 2, 3])
let b = set.from_list([2, 3, 4])

set.union(a, b)           // {1, 2, 3, 4}
set.intersection(a, b)    // {2, 3}
set.difference(a, b)      // {1}
set.contains(a, 2)        // => true
set.is_subset(a, b)       // => false