Re: Macros: Scheme vs Common Lisp

MS> Thus, in your example, MS> (setq bar 23) MS> [if done in fresh CL session] MS> creates a binding which associates 23 with BAR, and: MS> (setq bar 57) MS> modifies the binding created previously. I knew that already, thanks ;-) MS> Your example evaluates BAR at macro-definition time which surely MS> is not what you intended. (I.e., (foo) expands to 23, MS> regardless.) What I want is: MS> (setq 23) MS> (defmacro foo () 'bar) MS> (foo) => 23 MS> (let ((bar 42)) (foo)) => 23 [note: CL actually yields 42] MS> (setq bar 57) MS> (foo) => 57 MS> (let ((bar 42)) (foo)) => 57 [note: CL actually yields 42] But exactly this behaviour is what you get when you use (defmacro foo () bar) instead of (defmacro foo () 'bar): USER(2): (setq bar 23) 23 USER(9): (defmacro foo () bar) FOO USER(10): (foo) 23 USER(11): (let ((bar 42)) (foo)) 23 USER(12): (setq bar 57) 57 USER(13): (let ((bar 42)) (foo)) 57 USER(14): MS> Note that this is exactly what actually *would* happen if you MS> wrote: (defun foo () bar) instead of the defmacro. Yes. And that's why I was so surprised that you would want it otherwise (which I now see you don't). My point: yes, one can do what you want to do, also with Common Lisp. Your point (to which I agree): things can get somewhat hairy underway. Holger -- --- http://www.coling.uni-freiburg.de/~schauer --- ">grep schauer passwd "Das ist nur eine Shell. Bedenklich waere, wenn Dein LILO /vmunix.el bootet." -- Kristian und Holger in de.comp.os.linux.misc