Clamps Dictionary

ensure-prop

Macro

(ensure-prop proplist prop default)

Ensure that the property prop exists in proplist, otherwise set it to default. Return the value of prop.

Arguments

`proplist`	Property list.
`prop`	Keyword or Symbol denoting the property key to ensure.
`default`	The value the property should get assigned to if not set.

Examples

(defvar *proplist* '(:a 10 :b hello :c "world"))

(ensure-prop *proplist* :d 5)
;; => 5

*proplist* ; => (:d 5 :a 10 :b hello :c "world")

;; As property :a already exists, don't change it and return its
;; current value:

(ensure-prop *proplist* :a 3)
;; => 10

*proplist* ; => (:d 5 :a 10 :b hello :c "world")

Author: Orm Finnendahl

Created: 2025-02-18 Di 12:58

Validate