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package hashmap
import "encoding/json"
// Map is a persistent associative data structure mapping keys to values. It
// is immutable, and supports near-O(1) operations to create modified version of
// the map that shares the underlying data structure. Because it is immutable,
// all of its methods are safe for concurrent use.
type Map interface {
json.Marshaler
// Len returns the length of the map.
Len() int
// Index returns whether there is a value associated with the given key, and
// that value or nil.
Index(k interface{}) (interface{}, bool)
// Assoc returns an almost identical map, with the given key associated with
// the given value.
Assoc(k, v interface{}) Map
// Dissoc returns an almost identical map, with the given key associated
// with no value.
Dissoc(k interface{}) Map
// Iterator returns an iterator over the map.
Iterator() Iterator
}
// Iterator is an iterator over map elements. It can be used like this:
//
// for it := m.Iterator(); it.HasElem(); it.Next() {
// key, value := it.Elem()
// // do something with elem...
// }
type Iterator interface {
// Elem returns the current key-value pair.
Elem() (interface{}, interface{})
// HasElem returns whether the iterator is pointing to an element.
HasElem() bool
// Next moves the iterator to the next position.
Next()
}
// HasKey reports whether a Map has the given key.
func HasKey(m Map, k interface{}) bool {
_, ok := m.Index(k)
return ok
}
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