(t `(values ,@(cdr result) &optional)))))
`(function ,args ,result)))
+;;; a type specifier
+;;;
+;;; FIXME: The SB!KERNEL:INSTANCE here really means CL:CLASS.
+;;; However, the CL:CLASS type is only defined once PCL is loaded,
+;;; which is before this is evaluated. Once PCL is moved into cold
+;;; init, this might be fixable.
+(def!type type-specifier () '(or list symbol sb!kernel:instance))
+
;;; the default value used for initializing character data. The ANSI
;;; spec says this is arbitrary, so we use the value that falls
;;; through when we just let the low-level consing code initialize
;; just define ASSQ explicitly in terms of more primitive
;; operations:
(dolist (pair alist)
- (when (eq (car pair) item)
+ ;; though it may look more natural to write this as
+ ;; (AND PAIR (EQ (CAR PAIR) ITEM))
+ ;; the temptation to do so should be resisted, as pointed out by PFD
+ ;; sbcl-devel 2003-08-16, as NIL elements are rare in association
+ ;; lists. -- CSR, 2003-08-16
+ (when (and (eq (car pair) item) (not (null pair)))
(return pair))))
;;; like (DELETE .. :TEST #'EQ):
(error 'simple-type-error ; maybe should be TYPE-BUG, subclass of BUG?
:value value
:expected-type type
- :format-string "~@<~S ~_is not a ~_~S~:>"
+ :format-control "~@<~S ~_is not a ~_~S~:>"
:format-arguments (list value type)))
\f
;;; Return a function like FUN, but expecting its (two) arguments in
`(if ,test
(let ((it ,test)) (declare (ignorable it)),@body)
(acond ,@rest))))))
+
+\f
+;;; Delayed evaluation
+(defmacro delay (form)
+ `(cons nil (lambda () ,form)))
+
+(defun force (promise)
+ (cond ((not (consp promise)) promise)
+ ((car promise) (cdr promise))
+ (t (setf (car promise) t
+ (cdr promise) (funcall (cdr promise))))))
+
+(defun promise-ready-p (promise)
+ (or (not (consp promise))
+ (car promise)))