| 1 | package set |
| 2 | |
| 3 | import "sourcecraft.dev/bigbes/auxilia/collect" |
| 4 | |
| 5 | // Set is a generic set backed by map[T]struct{}. |
| 6 | type Set[T comparable] struct { |
| 7 | internal map[T]struct{} |
| 8 | } |
| 9 | |
| 10 | // NewSet creates an empty set with a capacity hint. |
| 11 | func NewSet[T comparable](expectedSize int) Set[T] { |
| 12 | return Set[T]{internal: make(map[T]struct{}, expectedSize)} |
| 13 | } |
| 14 | |
| 15 | // NewSetFromListFunc creates a set by applying f to each element of inp. |
| 16 | func NewSetFromListFunc[I any, T comparable](inp []I, f func(I) T) Set[T] { |
| 17 | s := NewSet[T](len(inp)) |
| 18 | for _, item := range inp { |
| 19 | s.Add(f(item)) |
| 20 | } |
| 21 | return s |
| 22 | } |
| 23 | |
| 24 | // Add inserts key into the set. It returns true if the key was newly added. |
| 25 | func (s *Set[T]) Add(key T) bool { |
| 26 | if _, exists := s.internal[key]; exists { |
| 27 | return false |
| 28 | } |
| 29 | s.internal[key] = struct{}{} |
| 30 | return true |
| 31 | } |
| 32 | |
| 33 | // Len returns the number of elements in the set. |
| 34 | func (s Set[T]) Len() int { |
| 35 | return len(s.internal) |
| 36 | } |
| 37 | |
| 38 | // Has reports whether key is in the set. |
| 39 | func (s Set[T]) Has(key T) bool { |
| 40 | _, ok := s.internal[key] |
| 41 | return ok |
| 42 | } |
| 43 | |
| 44 | // Delete removes key from the set. It returns true if the key existed. |
| 45 | func (s Set[T]) Delete(key T) bool { |
| 46 | if _, ok := s.internal[key]; !ok { |
| 47 | return false |
| 48 | } |
| 49 | delete(s.internal, key) |
| 50 | return true |
| 51 | } |
| 52 | |
| 53 | // Iterator returns a [collect.ListIterator] over the set elements. |
| 54 | // The iteration order is not guaranteed. |
| 55 | func (s Set[T]) Iterator() collect.ListIterator[T] { |
| 56 | keys := make([]T, 0, len(s.internal)) |
| 57 | for k := range s.internal { |
| 58 | keys = append(keys, k) |
| 59 | } |
| 60 | return collect.FromSlice(keys) |
| 61 | } |
| 62 | |