Assoc-Utils

Utilities for manipulating association lists.

Usage

aget

(defvar *person*
  '(("name" . "Eitaro") ("email" . "e.arrows@gmail.com")))

(aget *person* "name")
;=> "Eitaro"

(aget *person* "address")
;=> NIL

(aget *person* "address" "Tokyo, Japan")
;=> "Tokyo, Japan"

(setf (aget *person* "name") "Eitaro Fukamachi")

*person*
;=> (("name" . "Eitaro Fukamachi") ("email" . "e.arrows@gmail.com"))

alist-get

(defvar *data*
  '((:VERSION . "0.6")
    (:GENERATOR . "openstreetmap-cgimap 2.0.1 (1992 spike-08.openstreetmap.org)")
    (:COPYRIGHT . "OpenStreetMap and contributors")
    (:ATTRIBUTION . "http://www.openstreetmap.org/copyright")
    (:LICENSE . "http://opendatacommons.org/licenses/odbl/1-0/")
    (:ELEMENTS
     ((:TYPE . "node") (:ID . 1) (:LAT . 42.79572) (:LON . 13.569003)
      (:TIMESTAMP . "2024-09-13T11:52:01Z") (:VERSION . 39)
      (:CHANGESET . 156568263) (:USER . "SomeoneElse_Revert") (:UID . 1778799)
      (:TAGS (:|COMMUNICATION:MICROWAVE| . "yes") (:|COMMUNICATION:RADIO| . "fm")
       (:DESCRIPTION . "Radio Subasio") (:FREQUENCY . "105.5 MHz")
       (:MAN--MADE . "mast") (:NAME . "Monte Piselli - San Giacomo")
       (:NOTE . "This is the very first node on OpenStreetMap.")
       (:|TOWER:CONSTRUCTION| . "lattice") (:|TOWER:TYPE| . "communication"))))))

(alist-get *data* '(:elements 0 :tags :note))
;=> "This is the very first node on OpenStreetMap."

with-keys

The macro with-keys is the alist equivalent of with-slots.

(with-keys
   ("name" (loc "location") (time "time" 2024))
    (list (cons "name" "eitaro") (cons "location" "vienna"))
  (declare (string name))
  (setf loc (string-upcase loc))
  (format nil "Hi, ~a in ~a around ~a!" name loc time))
;; => "Hi, eitaro in VIENNA around 2024!"

The first parameter is a list of keys that with-keys will reference in the alist provided in the second parameter. With-keys will attempt to convert each key into a symbol, binding the alist value to it during body execution.

If you don't want with-keys to guess the symbol for a key, supply a list - (symbol key) - in place of the key, as in (loc "location") above. If the key is a number, you have to supply a symbol name since common lisp symbols can not consist of only numbers.

If you want to supply a default value, you have to supply a list - (symbol key default) - in place of the key, as in (time "time" 2024).

Code and documentation adapted from cl-hash-util.

remove-from-alist & delete-from-alist

(defvar *person*
  '(("name" . "Eitaro") ("email" . "e.arrows@gmail.com")))

(remove-from-alist *person* "name")
;=> (("email" . "e.arrows@gmail.com"))

;; Destructive version
(delete-from-alist *person* "name")
;=> (("email" . "e.arrows@gmail.com"))

alist-plist & plist-alist

(defvar *person*
  '(("name" . "Eitaro") ("email" . "e.arrows@gmail.com")))

(alist-plist *person*)
;=> (:NAME "Eitaro" :EMAIL "e.arrows@gmail.com")

(plist-alist '(:name "Eitaro" :email "e.arrows@gmail.com"))
;=> (("name" . "Eitaro") ("email" . "e.arrows@gmail.com"))

alist-hash & hash-alist

(defvar *person*
  '(("name" . "Eitaro") ("email" . "e.arrows@gmail.com")))

(alist-hash *person*)
;=> #<HASH-TABLE :TEST EQUAL :COUNT 2 {1004329443}>

(hash-alist *)
;=> (("name" . "Eitaro") ("email" . "e.arrows@gmail.com"))

alist-keys & alist-values

(defvar *person*
  '(("name" . "Eitaro") ("email" . "e.arrows@gmail.com")))

(alist-keys *person*)
;=> ("name" "email")

(alist-values *person*)
;=> ("Eitaro" "e.arrows@gmail.com")

alistp

(alistp '(("name" . "Eitaro") ("email" . "e.arrows@gmail.com")))
;=> T

(alistp 1)
;=> NIL

(alistp nil)
;=> T

;; Type: alist is also available
(typep '(("name" . "Eitaro") ("email" . "e.arrows@gmail.com")) 'alist)
;=> T

alist=

(alist= '(("name" . "Eitaro") ("email" . "e.arrows@gmail.com"))
        '(("email" . "e.arrows@gmail.com") ("name" . "Eitaro")))
;=> T

Installation

(ql:quickload :assoc-utils)

Author

• Eitaro Fukamachi (e.arrows@gmail.com)

License

Assoc-Utils is free and unencumbered software released into the public domain.