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Of course they can. But implementation-specific special forms must have macro-expansions...so if you fully-macroexpand, there can't be any implementation-specific special forms remaining -- just functions and standard special forms. The ANSI spec says that ... An implementation is free to implement...

Unfortunately there is no implementation independent way to do this since every implementations has it's own special forms. But usually the number of special forms is small wich makes it feasible to write different versions for different implementations. No. The special forms/operators are defined ...

Goheeca wrote:Konfusius your solution doesn't work for me, I get an output the same as an input.

I've corrected the bug. It should work, now. But your solution is better.

(defun do-replacement (expr) (setf expr (macroexpand expr)) (cond ((atom expr) expr) ((eq 'list (car expr)) (cons 'my-list (mapcar #'do-replacement (cdr expr)))) ((special-operator-p (car expr)) (case (car expr) ; special forms need special handling (quote expr) (let (list* 'let (mapcar (lambda (bi...

(define-condition pattern-maching-failed (error) ()) (defun rxvarp (exp) (if (and (consp exp) (= 2 (length exp)) (eq '? (car exp)) (symbolp (cadr exp))) (cadr exp))) (defun bind-rxvar (var exp bind) (let ((ent (assoc var bind))) (if ent (if (equalp (cdr ent) exp) bind (error 'pattern-maching-failed...

Variable lookup is done only in interpreted Lisps. In modern compiled Lisps the "lookup" cost of dynamic and lexical variables is the same as for global and local variables in C++.

The problem is your print-function which prints only the root node of the tree.

Mapcan operates destructively on the lists returned by the function. Because your function returns a literal list mapcan operates destructively on a literal object. The error will go away if you replace '(even) by (list 'even).

Eval can be useful if you want to write your own repl or interpreter. But in 99% of the cases where beginners tend to use eval there is a better solution using functional objects and funcall. It also executes much faster than eval. (setf z 666) (let ((z 14)) (print z) (funcall #'(lambda () (setf www...