Info Catalog cl: Control Structure cl: Generalized Variables

cl: Assignment

 
 4.1 Assignment
 ==============
 
 The ‘cl-psetq’ form is just like ‘setq’, except that multiple
 assignments are done in parallel rather than sequentially.
 
  -- Macro: cl-psetq [symbol form]...
      This special form (actually a macro) is used to assign to several
      variables simultaneously.  Given only one SYMBOL and FORM, it has
      the same effect as ‘setq’.  Given several SYMBOL and FORM pairs, it
      evaluates all the FORMs in advance and then stores the
      corresponding variables afterwards.
 
           (setq x 2 y 3)
           (setq x (+ x y)  y (* x y))
           x
                ⇒ 5
           y                     ; ‘y’ was computed after ‘x’ was set.
                ⇒ 15
           (setq x 2 y 3)
           (cl-psetq x (+ x y)  y (* x y))
           x
                ⇒ 5
           y                     ; ‘y’ was computed before ‘x’ was set.
                ⇒ 6
 
      The simplest use of ‘cl-psetq’ is ‘(cl-psetq x y y x)’, which
      exchanges the values of two variables.  (The ‘cl-rotatef’ form
      provides an even more convenient way to swap two variables; 
      Modify Macros.)
 
      ‘cl-psetq’ always returns ‘nil’.
 

Info Catalog cl: Control Structure cl: Generalized Variables