Add a convenience Of builder function to hashset (zyedidia#23)

Also update README to include doc for `Of`
shgopher · Jul 11, 2022 · 47c10d2 · 47c10d2
1 parent e61ed1b
commit 47c10d2
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diff --git a/hashset/README.md b/hashset/README.md
@@ -45,6 +45,7 @@ false
 
 - [type Set](<#type-set>)
   - [func New[K any](capacity uint64, equals g.EqualsFn[K], hash g.HashFn[K]) *Set[K]](<#func-new>)
+  - [func Of[K comparable](capacity uint64, equals g.EqualsFn[K], hash g.HashFn[K], vals ...K) *Set[K]](<#func-of>)
   - [func (s *Set[K]) Copy() *Set[K]](<#func-setk-copy>)
   - [func (s *Set[K]) Each(fn func(key K))](<#func-setk-each>)
   - [func (s *Set[K]) Has(val K) bool](<#func-setk-has>)
@@ -71,6 +72,14 @@ func New[K any](capacity uint64, equals g.EqualsFn[K], hash g.HashFn[K]) *Set[K]
 
 New returns an empty hashset\.
 
+### func [Of](<https://github.com/zyedidia/generic/blob/master/hashset/set.go#L22>)
+
+```go
+func Of[K comparable](capacity uint64, equals g.EqualsFn[K], hash g.HashFn[K], vals ...K) *Set[K]
+```
+
+Of returns a new hashset initialized with the given values\.
+
 ### func \(\*Set\[K\]\) [Copy](<https://github.com/zyedidia/generic/blob/master/hashset/set.go#L50>)
 
 ```go

diff --git a/hashset/set.go b/hashset/set.go
@@ -18,6 +18,15 @@ func New[K any](capacity uint64, equals g.EqualsFn[K], hash g.HashFn[K]) *Set[K]
 	}
 }
 
+// Of returns a new hashset initialized with the given 'vals'
+func Of[K comparable](capacity uint64, equals g.EqualsFn[K], hash g.HashFn[K], vals ...K) *Set[K] {
+	s := New[K](capacity, equals, hash)
+	for _, val := range vals {
+		s.Put(val)
+	}
+	return s
+}
+
 // Put adds 'val' to the set.
 func (s *Set[K]) Put(val K) {
 	s.m.Put(val, struct{}{})

diff --git a/hashset/set_test.go b/hashset/set_test.go
@@ -46,6 +46,30 @@ func TestCrossCheck(t *testing.T) {
 	}
 }
 
+func TestOf(t *testing.T) {
+	testcases := []struct {
+		name  string
+		input []string
+	}{
+		{"init with several items", []string{"foo", "bar", "baz"}},
+		{"init without values", []string{}},
+	}
+	for _, tc := range testcases {
+		t.Run(tc.name, func(t *testing.T) {
+			set := hashset.Of[string](10, g.Equals[string], g.HashString, tc.input...)
+
+			if len(tc.input) != set.Size() {
+				t.Fatalf("expected %d elements in set, got %d", len(tc.input), set.Size())
+			}
+			for _, val := range tc.input {
+				if !set.Has(val) {
+					t.Fatalf("expected to find val '%s' in set but did not", val)
+				}
+			}
+		})
+	}
+}
+
 func Example() {
 	set := hashset.New[string](3, g.Equals[string], g.HashString)
 	set.Put("foo")