hier-set

A "hierarchical set" data structure for Clojure has elements in a defined hierarchical relationship. An element is a member if it is a primary member or a descendant of a primary member. Lookup returns set membership and all primary members that are ancestors of the lookup element.

Stack

Why

The element sort-order and a separate containment predicate define the hierarchical relationship. These constraints apply:

• Elements must sort before any descendants.
• Elements must contain all elements that sort between themselves and any descendant.

Use this library for simple hierarchical systems. The hierarchy is implicit in the entities, such as the Java package system, hierarchical filesystems, or IP networks. Do not use this library for complex ad hoc hierarchies, such as relationships between classes with multiple inheritance.

Installation

Clojure CLI (deps.edn):

net.clojars.savya/hier-set {:mvn/version "1.2.3"}

Leiningen (project.clj):

[net.clojars.savya/hier-set "1.2.3"]

Run tests with clojure -M:test. Build the JAR with clojure -T:build jar, or deploy with clojure -T:build deploy.

Usage

Use the hier-set and hier-set-by constructor functions in the hier-set.core namespace. The hier-set.core/ancestors and hier-set.core/descendants functions return lazy sequences of the ancestors and descendants of a provided key.

Compatibility

The library requires Clojure 1.10 or later and JDK 8 or later. The library is continuously tested against Clojure 1.10.3, 1.11.4, and 1.12.5 on JDK 8, 11, 17, and 21.

Example

A basic 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")

License

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.