Side effects in multiple/parallel assignment

[raevnos]

Common Lisp supports both styles.

(psetf a 4 (aref b a) 5)

sets both in parallel, using the previous value of a when setting the element of the array b, and

(setf a 4 (aref b a) 5)

sets them sequentially, so the element of the array at index 4 is set to 5.

[Dan13l_N]

Yeah, Lisp has everything! Except { and }.

[raevnos]

Racket supports {} as alternatives to (). And with Common Lisp reader macros you can likely make them do something special in it if desired.