*READ-EVAL* T
*READ-SUPPRESS* NIL
*READTABLE* the standard readtable"
- `(%with-standard-io-syntax #'(lambda () ,@body)))
+ `(%with-standard-io-syntax (lambda () ,@body)))
(defun %with-standard-io-syntax (function)
(let ((*package* (find-package "COMMON-LISP-USER"))
;;; Check to see whether OBJECT is a circular reference, and return
;;; something non-NIL if it is. If ASSIGN is T, then the number to use
;;; in the #n= and #n# noise is assigned at this time.
+;;; If ASSIGN is true, reference bookkeeping will only be done for
+;;; existing entries, no new references will be recorded!
;;;
;;; Note: CHECK-FOR-CIRCULARITY must be called *exactly* once with
;;; ASSIGN true, or the circularity detection noise will get confused
;;; about when to use #n= and when to use #n#. If this returns non-NIL
;;; when ASSIGN is true, then you must call HANDLE-CIRCULARITY on it.
-;;; If you are not using this inside a WITH-CIRCULARITY-DETECTION,
-;;; then you have to be prepared to handle a return value of :INITIATE
-;;; which means it needs to initiate the circularity detection noise.
+;;; If CHECK-FOR-CIRCULARITY returns :INITIATE as the second value,
+;;; you need to initiate the circularity detection noise, e.g. bind
+;;; *CIRCULARITY-HASH-TABLE* and *CIRCULARITY-COUNTER* to suitable values
+;;; (see #'OUTPUT-OBJECT for an example).
(defun check-for-circularity (object &optional assign)
(cond ((null *print-circle*)
;; Don't bother, nobody cares.
nil)
((null *circularity-hash-table*)
- :initiate)
+ (values nil :initiate))
((null *circularity-counter*)
(ecase (gethash object *circularity-hash-table*)
((nil)
;;; that there is no pretty printer installed.
(defvar *pretty-printer* nil)
+;;; Objects whose print representation identifies them EQLly don't
+;;; need to be checked for circularity.
+(defun uniquely-identified-by-print-p (x)
+ (or (numberp x)
+ (characterp x)
+ (and (symbolp x)
+ (symbol-package x))))
+
;;; Output OBJECT to STREAM observing all printer control variables.
(defun output-object (object stream)
(labels ((print-it (stream)
(output-ugly-object object stream)))
(output-ugly-object object stream)))
(check-it (stream)
- (let ((marker (check-for-circularity object t)))
- (case marker
- (:initiate
- (let ((*circularity-hash-table*
+ (multiple-value-bind (marker initiate)
+ (check-for-circularity object t)
+ ;; initialization of the circulation detect noise ...
+ (if (eq initiate :initiate)
+ (let ((*circularity-hash-table*
(make-hash-table :test 'eq)))
- (check-it (make-broadcast-stream))
- (let ((*circularity-counter* 0))
- (check-it stream))))
- ((nil)
- (print-it stream))
- (t
- (when (handle-circularity marker stream)
- (print-it stream)))))))
- (cond ((or (not *print-circle*)
- (numberp object)
- (characterp object)
- (and (symbolp object)
- (symbol-package object)))
- ;; If it's a number, character, or interned symbol, we
- ;; don't want to check for circularity/sharing.
+ (check-it (make-broadcast-stream))
+ (let ((*circularity-counter* 0))
+ (check-it stream)))
+ ;; otherwise
+ (if marker
+ (when (handle-circularity marker stream)
+ (print-it stream))
+ (print-it stream))))))
+ (cond (;; Maybe we don't need to bother with circularity detection.
+ (or (not *print-circle*)
+ (uniquely-identified-by-print-p object))
(print-it stream))
- ((or *circularity-hash-table*
- (consp object)
- (typep object 'instance)
- (typep object '(array t *)))
- ;; If we have already started circularity detection, this
+ (;; If we have already started circularity detection, this
;; object might be a shared reference. If we have not, then
- ;; if it is a cons, an instance, or an array of element
- ;; type T it might contain a circular reference to itself
- ;; or multiple shared references.
+ ;; if it is a compound object it might contain a circular
+ ;; reference to itself or multiple shared references.
+ (or *circularity-hash-table*
+ (compound-object-p object))
(check-it stream))
(t
(print-it stream)))))
+;;; a hack to work around recurring gotchas with printing while
+;;; DEFGENERIC PRINT-OBJECT is being built
+;;;
+;;; (hopefully will go away naturally when CLOS moves into cold init)
+(defvar *print-object-is-disabled-p*)
+
;;; Output OBJECT to STREAM observing all printer control variables
;;; except for *PRINT-PRETTY*. Note: if *PRINT-PRETTY* is non-NIL,
;;; then the pretty printer will be used for any components of OBJECT,
;; a method on an external symbol in the CL package which is
;; applicable to arg lists containing only direct instances of
;; standardized classes.
- ;; Thus, in order for the user to detect our sleaziness, he has to do
- ;; something relatively obscure like
+ ;; Thus, in order for the user to detect our sleaziness in conforming
+ ;; code, he has to do something relatively obscure like
;; (1) actually use tools like FIND-METHOD to look for PRINT-OBJECT
;; methods, or
;; (2) define a PRINT-OBJECT method which is specialized on the stream
;; value (e.g. a Gray stream object).
;; As long as no one comes up with a non-obscure way of detecting this
;; sleaziness, fixing this nonconformity will probably have a low
- ;; priority. -- WHN 20000121
+ ;; priority. -- WHN 2001-11-25
(fixnum
(output-integer object stream))
(list
(output-symbol object stream)
(output-list object stream)))
(instance
- (print-object object stream))
+ (cond ((not (and (boundp '*print-object-is-disabled-p*)
+ *print-object-is-disabled-p*))
+ (print-object object stream))
+ ((typep object 'structure-object)
+ (default-structure-print object stream *current-level*))
+ (t
+ (write-string "#<INSTANCE but not STRUCTURE-OBJECT>" stream))))
(function
(unless (and (funcallable-instance-p object)
(printed-as-funcallable-standard-class object stream))
\f
;;;; symbols
-;;; Values of *PRINT-CASE* and (READTABLE-CASE *READTABLE*) the last
-;;; time the printer was called.
+;;; values of *PRINT-CASE* and (READTABLE-CASE *READTABLE*) the last
+;;; time the printer was called
(defvar *previous-case* nil)
(defvar *previous-readtable-case* nil)
(output-object (pop list) stream)
(unless list
(return))
- (when (or (atom list) (check-for-circularity list))
+ (when (or (atom list)
+ (check-for-circularity list))
(write-string " . " stream)
(output-object list stream)
(return))
projects / sbcl.git / blobdiff