work on HashMap and slices

map.go

@@ -0,0 +1,46 @@
+package laniakea
+
+type HashMap[K comparable, V any] map[K]V
+
+func NewMapFrom[K comparable, V any](m map[K]V) HashMap[K, V] {
+	out := make(HashMap[K, V])
+	for k, v := range m {
+		out[k] = v
+	}
+	return out
+}
+func (m HashMap[K, V]) Len() int {
+	return len(m)
+}
+func (m HashMap[K, V]) Add(key K, val V) HashMap[K, V] {
+	m[key] = val
+	return m
+}
+func (m HashMap[K, V]) Remove(key K) HashMap[K, V] {
+	delete(m, key)
+	return m
+}
+func (m HashMap[K, V]) Get(key K) V {
+	return m[key]
+}
+func (m HashMap[K, V]) GetOrDefault(key K, def V) V {
+	v, ok := m[key]
+	if !ok {
+		return def
+	}
+	return v
+}
+func (m HashMap[K, V]) Contains(key K) bool {
+	_, ok := m[key]
+	return ok
+}
+func (m HashMap[K, V]) Filter(f func(K, V) bool) HashMap[K, V] {
+	out := make(HashMap[K, V])
+	for k, v := range m {
+		if !f(k, v) {
+			continue
+		}
+		out[k] = v
+	}
+	return out
+}