Neil Cerutti schrieb: > On 2006-12-12, André Thieme <[EMAIL PROTECTED]> wrote: > >> Contrast the much more common > >> > >> a[i] = b[n] > >> > >> with > >> > >> (setf (aref a i) (aref b n)) > >> > >> and the attractions of Python may make more sense. > > > > Here Python and Lisp are equal, 7 tokens vs 7 tokens, but in > > Python one has to write less since "[]" are 2 chars while > > "aref" are 4, plus the setf. But from counting the brain units > > which I regard as an important factor they are both equal. > > A comparison of brain units of the above snippets is irrelevant, > since the snippets are not equivalent. > > The Python snippet will work for any object a that provides > __setitem__ and any object b that provides __getitem__. > > I don't know what an equivalent Lisp snippet would be (or even > exactly how close the above snippet comes to matching the Python > code), but whatever it is would be a better foundation for > comparing brain units with the above Python.
It would be exactly like the example given, just "aref" replaced with something else. An example implementation: ========================================== (defgeneric $ (container key)) (defgeneric (setf $) (value container key)) ;;; Implementation for arrays (defmethod $ ((container array) (key integer)) (aref container key)) (defmethod (setf $) (value (container array) (key integer)) (setf (aref container key) value)) ========================================== And usage: ========================================== CL-USER(3): (defparameter a (vector 1 2 3 4 5)) A CL-USER(4): ($ a 0) 1 CL-USER(5): (setf ($ a 0) 9) 9 CL-USER(6): a #(9 2 3 4 5) ========================================== The nice thing is, that you *can* dispatch on the container, the key and the value. -- http://mail.python.org/mailman/listinfo/python-list
