Elisp: Symbol Property List

Each lisp symbol is associated with a “property list”.

[see Elisp: Property List]

This property list is stored in the symbol's property list cell. [see Elisp: Lisp Symbol]

Emacs lisp property list is used extensively in emacs. It is also very useful if you want to write a function with state. You can store the state info with the symbol itself, instead of using a global variable.

Set Whole Plist

(setplist SYMBOL NEWPLIST) → Set SYMBOL's property list to NEWPLIST, and return NEWPLIST.

;; set the value of symbol ff's property list
(setplist 'ff '(a 1 b 2))

Get Whole Plist

(symbol-plist SYMBOL) → Return SYMBOL's property list.

;; get the value of symbol ff's property list
(symbol-plist 'ff )

Add/Set a Key's Value

(put SYMBOL PROPNAME VALUE) → Store SYMBOL's PROPNAME property with value VALUE.

;; set the value of key xx, of symbol ff's property list
(put 'ff 'xx 5)

Get a Key's Value

(get SYMBOL PROPNAME) → Return the value of SYMBOL's PROPNAME property.

;; get the value of key xx, of symbol ff's property list
(get 'ff 'xx)

Reference

(info "(elisp) Symbol Properties")

Example of Using Symbol Properties

Elisp: How to Write a Toggle Command