A "hierarchical set" data structure for Clojure: a set of elements with a defined hierarchical relationship, where an element is a member if it is a primary member or a descendant of one. Lookup returns set membership and all primary members that are ancestors of the lookup element.
The hierarchical relationship is defined by the element sort-order and a separate containment predicate, with the following constraints:
- elements must sort prior to any descendants; and
- elements must contain all elements which sort between themselves and any descendant.
This is sufficient to represent simple hierarchical systems where the hierarchy is implicit in the entities involved, such as the Java package system, hierarchical filesystems, or IP networks. It is inappropriate for modeling complex, ad hoc hierarchies, such as the relationships between classes with multiple inheritance.
Leiningen (project.clj):
[net.clojars.savya/hier-set "1.2.1"]Clojure CLI (deps.edn):
net.clojars.savya/hier-set {:mvn/version "1.2.1"}Primary usage is then through the hier-set and hier-set-by constructor
functions in the hier-set.core namespace. In addition to set lookup as
described above, the hier-set.core/ancestors and hier-set.core/descendants
functions also provide access to lazy sequences of the ancestors and
descendants respectively of a provided key.
Requires Clojure 1.10 or later and JDK 8 or later. Continuously tested against Clojure 1.10.3, 1.11.4, and 1.12.5 on JDK 8, 11, 17, and 21.
A trivial example:
(ns example.hier-set
(:require [hier-set.core :as hs :refer [hier-set]]))
(def starts-with? #(.startsWith %2 %1))
(def h (hier-set starts-with? "ack" "foo" "foo.bar" "quux"))
(get h "bar") ;;=> nil
(get h "foo") ;;=> ("foo")
(get h "foo.bar.baz") ;;=> ("foo.bar" "foo")
(hs/ancestors h "bar") ;;=> ()
(hs/ancestors h "foo.baz") ;;=> ("foo")
(hs/descendants h "foo") ;;=> ("foo" "foo.bar")Copyright © 2012, 2014 Marshall Bockrath-Vandegrift.
Maintenance fork (2026) by Savyasachi, original: https://github.com/llasram/hier-set. Distributed under the Eclipse Public License 1.0, preserving the original license.
Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.