What if x and y may be assigned, but their evaluation has side effects (e.g., array[i++])? Common Lisp's most interesting contribution to this discussion is th

What if x and y may be assigned, but their evaluation has side effects (e.g., array[i++])? Common Lisp's most interesting contribution to this discussion is that places (~lvalues) are (should be) expressed in a common framework which lets macros use standard helpers like get-setf-expansion http://www.lispworks.com/documentation/HyperSpec/Body/f_get_se.htm http://www.lispworks.com/documentation/HyperSpec/Body/f_get_... to avoid doubly evaluating subexpressions.