(SETF GETF) is buggy

Question

Gleefre opened this issue a year ago · comments

(let ((x (list :a 10 :b 20)))
  (setf (getf x :b) 0)
  x)
; => (:B 0)
;; should be: (:A 10 :B 0)

If I understand it correctly, it should be (return plist) instead.

Svante von Erichsen · Answer 1 · Mon Jul 31 2023 20:55:50 GMT+0800 (China Standard Time)

To be honest, the spec doesn't specify what setf of getf should return. The example shows it returning the value it set.

Gleefre · Answer 2 · Mon Jul 31 2023 21:03:04 GMT+0800 (China Standard Time)

The problem is not in the return value of (SETF GETF) but in the side effect of discarding the property :A

Svante von Erichsen · Answer 3 · Mon Jul 31 2023 21:25:16 GMT+0800 (China Standard Time)

Ah, sorry, overlooked that you returned the plist. Very well, proceed ^^.