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Actually, in Common Lisp, () is equivalent to (reads as) NIL, which is self-evaluating, so it's a completely legitimate way of writing the empty list. (Which does not mean it isn't stylistically questionable.)

http://www.lispworks.com/documentation/HyperSpec/Body/03_dad.htm : For each keyword parameter specifier, if there is an argument pair whose name matches that specifier's name (that is, the names are eq), then the parameter variable for that specifier is bound to the second item (the value) of that ...

If there is more than one variable with the same value, are there two places in memory with the same value or do they both point to the same address in memory? It depends on what you mean by “same.” When you have an object with identity, such as an array, a list, a struct, a CLOS class instance...

Macros run (are expanded) at compile-time. Functions run at run-time. Hence, functions cannot call macros. A macro form can appear in a function's body, of course. But the same principle applies: The macro is expanded during compilation, not when the function is called. Assuming you have the followi...

Or use Drakma.

When in doubt, use late binding. (By which I mean “use symbols.”)
Since symbols are funcallable, this will solve your problem.

This is your code, correctly formatted: (defun choices (loc) (if (eql loc 'library) (append '((east upstairs-bedroom)) '((south back-stairs)))) (if (eql loc 'dining-room) (append '((east pantry)) '((west downstairs-bedroom)) '((north living-room)))) (if (eql loc 'back-stairs) (append '((north librar...

wvxvw wrote:(I don't say it become better - it's just I didn't realize `member' will act like `eq' rather than `equal')

You can tell MEMBER to use EQUAL by doing (MEMBER ... :TEST #'EQUAL).

You can always use apply, of course, but it probably won't exactly improve the stack traces you see in the debugger.
If you want to portably do better than that, you might have to do code walking.

For an ad-hoc, SBCL-specific hack like that, you can parse the return value of the lisp-implementation-version function. (defun parsed-lisp-implementation-version () (loop for ver = (lisp-implementation-version) then (subseq ver (1+ pos)) for pos = (position #\. ver) collect (parse-integer (if pos (...