s))
(defvar *print-escape* t)
+(defvar *print-circle* nil)
-(defun write-to-string (form)
- (cond
- ((null form) "NIL")
- ((symbolp form)
- (let ((name (symbol-name form))
- (package (symbol-package form)))
- ;; Check if the symbol is accesible from the current package. It
- ;; is true even if the symbol's home package is not the current
- ;; package, because it could be inherited.
- (if (eq form (find-symbol (symbol-name form)))
- (escape-token (symbol-name form) (not (eq package *js-package*)))
- ;; Symbol is not accesible from *PACKAGE*, so let us prefix
- ;; the symbol with the optional package or uninterned mark.
- (concat (cond
- ((null package) "#")
- ((eq package (find-package "KEYWORD")) "")
- (t (escape-token (package-name package) t)))
- ":"
- (if (and package
- (eq (second (multiple-value-list
- (find-symbol name package)))
- :internal))
- ":"
- "")
- (escape-token name (not (eq package *js-package*)))))))
- ((integerp form) (integer-to-string form))
- ((floatp form) (float-to-string form))
- ((characterp form)
- (concat "#\\"
- (case form
- (#\newline "newline")
- (#\space "space")
- (otherwise (string form)))))
- ((stringp form) (if *print-escape*
- (concat "\"" (escape-string form) "\"")
- form))
- ((functionp form)
- (let ((name (oget form "fname")))
- (if name
- (concat "#<FUNCTION " name ">")
- (concat "#<FUNCTION>"))))
- ((listp form)
- (concat "("
- (join-trailing (mapcar #'write-to-string (butlast form)) " ")
- (let ((last (last form)))
- (if (null (cdr last))
- (write-to-string (car last))
- (concat (write-to-string (car last)) " . " (write-to-string (cdr last)))))
- ")"))
- ((arrayp form)
- (concat "#" (if (zerop (length form))
- "()"
- (write-to-string (vector-to-list form)))))
- ((packagep form)
- (concat "#<PACKAGE " (package-name form) ">"))
- (t
- (concat "#<javascript object>"))))
+(defun write-to-string (form &optional known-objects object-ids)
+ (when (and (not known-objects) *print-circle*)
+ ;; To support *print-circle* some objects must be tracked for
+ ;; sharing: conses, arrays and apparently-uninterned symbols.
+ ;; These objects are placed in an array and a parallel array is
+ ;; used to mark if they're found multiple times by assining them
+ ;; an id starting from 1.
+ ;;
+ ;; After the tracking has been completed the printing phas can
+ ;; begin: if an object has an id > 0 then #<n>= is prefixed and
+ ;; the id is changed to negative. If an object has an id < 0 then
+ ;; #<-n># is printed instead of the object.
+ ;;
+ ;; The processing is O(n^2) with n = number of tracked objects,
+ ;; but it should be reasonably fast because is based on afind that
+ ;; is a primitive function that compiles to [].indexOf.
+ (setf known-objects (make-array 100))
+ (setf object-ids (make-array 100))
+ (let ((n 0)
+ (sz 100)
+ (count 0))
+ (labels ((mark (x)
+ (let ((i (afind x known-objects)))
+ (if (= i -1)
+ (progn
+ (when (= n sz)
+ (setf sz (* 2 sz))
+ (aresize known-objects sz)
+ (aresize object-ids sz))
+ (aset known-objects (1- (incf n)) x)
+ t)
+ (unless (aref object-ids i)
+ (aset object-ids i (incf count))
+ nil))))
+ (visit (x)
+ (cond
+ ((and x (symbolp x) (null (symbol-package x)))
+ (mark x))
+ ((consp x)
+ (when (mark x)
+ (visit (car x))
+ (visit (cdr x))))
+ ((arrayp x)
+ (when (mark x)
+ (dotimes (i (length x))
+ (visit (aref x i))))))))
+ (visit form))))
+ (let ((prefix ""))
+ (when (and *print-circle*
+ (or (consp form)
+ (arrayp form)
+ (and form (symbolp form) (null (symbol-package form)))))
+ (let* ((ix (afind form known-objects))
+ (id (aref object-ids ix)))
+ (cond
+ ((and id (> id 0))
+ (setf prefix (format nil "#~S=" id))
+ (aset object-ids ix (- id)))
+ ((and id (< id 0))
+ (return-from write-to-string (format nil "#~S#" (- id)))))))
+ (concat prefix
+ (cond
+ ((null form) "NIL")
+ ((symbolp form)
+ (let ((name (symbol-name form))
+ (package (symbol-package form)))
+ ;; Check if the symbol is accesible from the current package. It
+ ;; is true even if the symbol's home package is not the current
+ ;; package, because it could be inherited.
+ (if (eq form (find-symbol (symbol-name form)))
+ (escape-token (symbol-name form) (not (eq package *js-package*)))
+ ;; Symbol is not accesible from *PACKAGE*, so let us prefix
+ ;; the symbol with the optional package or uninterned mark.
+ (concat (cond
+ ((null package) "#")
+ ((eq package (find-package "KEYWORD")) "")
+ (t (escape-token (package-name package) t)))
+ ":"
+ (if (and package
+ (eq (second (multiple-value-list
+ (find-symbol name package)))
+ :internal))
+ ":"
+ "")
+ (escape-token name (not (eq package *js-package*)))))))
+ ((integerp form) (integer-to-string form))
+ ((floatp form) (float-to-string form))
+ ((characterp form)
+ (concat "#\\"
+ (case form
+ (#\newline "newline")
+ (#\space "space")
+ (otherwise (string form)))))
+ ((stringp form) (if *print-escape*
+ (concat "\"" (escape-string form) "\"")
+ form))
+ ((functionp form)
+ (let ((name (oget form "fname")))
+ (if name
+ (concat "#<FUNCTION " name ">")
+ (concat "#<FUNCTION>"))))
+ ((listp form)
+ (concat "("
+ (join-trailing (mapcar (lambda (x)
+ (write-to-string x known-objects object-ids))
+ (butlast form)) " ")
+ (let ((last (last form)))
+ (if (null (cdr last))
+ (write-to-string (car last) known-objects object-ids)
+ (concat (write-to-string (car last) known-objects object-ids)
+ " . "
+ (write-to-string (cdr last) known-objects object-ids))))
+ ")"))
+ ((arrayp form)
+ (let ((result "(")
+ (sep ""))
+ (dotimes (i (length form))
+ (setf result (concat result sep
+ (write-to-string (aref form i)
+ known-objects
+ object-ids)))
+ (setf sep " "))
+ (concat result ")")))
+ ((packagep form)
+ (concat "#<PACKAGE " (package-name form) ">"))
+ (t "#<javascript object>")))))
(defun prin1-to-string (form)
(let ((*print-escape* t))
projects / jscl.git / commitdiff