elisp: Plist Access
5.9.2 Property Lists Outside Symbols
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The following functions can be used to manipulate property lists. They
all compare property names using ‘eq’.
-- Function: plist-get plist property
This returns the value of the PROPERTY property stored in the
property list PLIST. It accepts a malformed PLIST argument. If
PROPERTY is not found in the PLIST, it returns ‘nil’. For example,
(plist-get '(foo 4) 'foo)
⇒ 4
(plist-get '(foo 4 bad) 'foo)
⇒ 4
(plist-get '(foo 4 bad) 'bad)
⇒ nil
(plist-get '(foo 4 bad) 'bar)
⇒ nil
-- Function: plist-put plist property value
This stores VALUE as the value of the PROPERTY property in the
property list PLIST. It may modify PLIST destructively, or it may
construct a new list structure without altering the old. The
function returns the modified property list, so you can store that
back in the place where you got PLIST. For example,
(setq my-plist '(bar t foo 4))
⇒ (bar t foo 4)
(setq my-plist (plist-put my-plist 'foo 69))
⇒ (bar t foo 69)
(setq my-plist (plist-put my-plist 'quux '(a)))
⇒ (bar t foo 69 quux (a))
-- Function: lax-plist-get plist property
Like ‘plist-get’ except that it compares properties using ‘equal’
instead of ‘eq’.
-- Function: lax-plist-put plist property value
Like ‘plist-put’ except that it compares properties using ‘equal’
instead of ‘eq’.
-- Function: plist-member plist property
This returns non-‘nil’ if PLIST contains the given PROPERTY.
Unlike ‘plist-get’, this allows you to distinguish between a
missing property and a property with the value ‘nil’. The value is
actually the tail of PLIST whose ‘car’ is PROPERTY.
Info Catalog
elisp: Plists and Alists
elisp: Property Lists