I was trying to pop an element of a list in elisp as follows,
(pop '(1 2))
but, due to my misunderstanding, that doesn't work b/c the list hasn't been internalized as a symbol. Is there an idiomatic way to do the above, or is that not a proper approach? Messing around a bit further I found I could do
(pop (progn (setq tmp '(1 2)) tmp))
but it doesn't seem right. Is there a way to make anonymous lists and modify them in place like I was trying to do?
pop is a macro
which modifies the value of its argument,
a place.
E.g.,
(defparameter *var* '(1 2 3))
(pop *var*)
==> 1
*var*
==> (2 3)
Note that what gets modified is the value of the place, not the object contained in the place.
E.g.,
(defparameter *var-1* '(1 2 3))
(defparameter *var-2* *var-1*)
(pop *var-1*)
==> 1
*var-1*
==> (2 3)
*var-2*
==> (1 2 3)
IOW, the list (1 2 3) is not modified, only the value of the variable is.
What exactly are you trying to do?