Custom Query (1030 matches)

Hello.

CCL does not accept multiple :CONSTRUCTOR options in DEFSTRUCT macro at the moment.

i.e. (defstruct (my-struct (:constructor make-my-struct) (:constructor my-struct)))

Error: Duplicate (:CONSTRUCTOR MY-STRUCT) options not allowed

While executing: DEFSTRUCT, in process listener(1).

This is an incompatibility with ANSI CL standard, which allows multiple constructor options: ​http://www.lispworks.com/documentation/HyperSpec/Body/m_defstr.htm

The sharp-double-quote example in Let Over Lisp requires the addition of an extra " at the end of the expression in order to allow return to evaluate the expression in the REPL. The following code:

(defun |#"-reader| (stream sub-char numarg)
  (declare (ignore sub-char numarg))
  (let (chars)
    (do ((prev (read-char stream) curr)
         (curr (read-char stream) (read-char stream)))
        ((and (char= prev #\") (char= curr #\#)))
      (push prev chars))
    (coerce (nreverse chars) 'string)))

(set-dispatch-macro-character 
 #\# #\" #'|#"-reader|)

should produce a the following:

? #"contains " and \."#
"contains \" and \\."

However, to produce that result you'll have to add an additional " to the end of the expression, which shouldn't be required.

When *print-circle* is T, FORMAT uses three times as much memory when printing conses compared to 1.9-r15757 (LinuxX8664), for example:

(defun test () (dotimes (k 100000) (format () "~a" '((a) (b)))))
(time (test))

Runtime is also increased, by ca. 25%

When *print-circle* is nil, the increase in memory usage is even bigger (almost tenfold).