Jakub Zych
a0bf8ece05
- Add TryMap, Filter, Reduce, KeyBy, GroupBy, Uniq, UniqBy, Partition and Find, plus the Set type built with SetOf (Has, Add, Slice). - Add unit tests at 100% statement coverage and a runnable example for every function and Set method. - Complete the module README: contracts, use cases, Pluck rationale, standard-library pointers and the full API reference. - docs/architecture/introduction.md: add a Utilities row for sieve. - docs/setup/coming-from-wintercms.md: map Laravel collection methods to sieve and narrow the not-provided row to the fluent collection object.
44 lines
1.3 KiB
Go
44 lines
1.3 KiB
Go
package sieve
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// Set is a set of comparable values backed by a plain map, so len, range,
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// delete and maps.Keys work on it directly. Create sets with SetOf: Has and
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// Slice work on a nil Set, but Add on a nil Set panics like any write to a nil
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// map. Slice returns the elements in unspecified order; use
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// slices.Sorted(maps.Keys(set)) for ordered output when T is ordered.
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type Set[T comparable] map[T]struct{}
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// SetOf returns a new set holding items, without duplicates. SetOf() with no
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// arguments returns an empty, non-nil set that Add can use. It accepts a slice
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// spread with ..., including a named slice type.
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func SetOf[T comparable](items ...T) Set[T] {
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s := make(Set[T], len(items))
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for _, v := range items {
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s[v] = struct{}{}
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}
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return s
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}
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// Has reports whether v is in the set. A nil Set has no elements.
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func (s Set[T]) Has(v T) bool {
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_, ok := s[v]
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return ok
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}
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// Add puts items into the set; items already present are ignored. Add on a nil
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// Set panics, so create sets with SetOf.
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func (s Set[T]) Add(items ...T) {
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for _, v := range items {
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s[v] = struct{}{}
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}
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}
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// Slice returns a new slice holding each element of the set exactly once, in
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// unspecified order. It is non-nil even for an empty or nil Set.
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func (s Set[T]) Slice() []T {
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out := make([]T, 0, len(s))
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for v := range s {
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out = append(out, v)
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}
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return out
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}
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