X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fread.lisp;h=6e9eb68cc751bcb7e6d6c411e08e43bbfcdc061b;hb=2b13192a8855e3b59966b41d86f94b614cfafeba;hp=a282a67de7f9ee8e1558bc7ff768005b92bb67e4;hpb=9d06dad66c317af94030e12a8d316b9777164a2f;p=jscl.git

diff --git a/src/read.lisp b/src/read.lisp
index a282a67..6e9eb68 100644
--- a/src/read.lisp
+++ b/src/read.lisp
@@ -16,12 +16,60 @@
 ;; You should have received a copy of the GNU General Public License
 ;; along with JSCL.  If not, see <http://www.gnu.org/licenses/>.
 
+(/debug "loading read.lisp!")
 
 ;;;; Reader
 
 ;;; The Lisp reader, parse strings and return Lisp objects. The main
 ;;; entry points are `ls-read' and `ls-read-from-string'.
 
+;;; #= / ## implementation
+
+;; For now associations label->object are kept in a plist
+;; May be it makes sense to use a vector instead if speed
+;; is considered a problem with many labelled objects
+(defvar *labelled-objects* nil)
+
+(defun new-labelled-objects-table ()
+  (setf *labelled-objects* nil))
+
+(defun find-labelled-object (id)
+  (assoc id *labelled-objects*))
+
+(defun add-labelled-object (id value)
+  (push (cons id value) *labelled-objects*))
+
+;; A unique value used to mark in the labelled objects
+;; table an object that is being constructed
+;; (e.g. #1# while reading elements of "#1=(#1# #1# #1#)")
+(defvar *future-value* (make-symbol "future"))
+
+;; A unique value used to mark temporary values that will
+;; be replaced when fixups are run.
+(defvar *fixup-value* (make-symbol "fixup"))
+
+;; Fixup locations keeps a list of conses where the CAR
+;; is a callable to be called with the value of the object
+;; associated to label stored in CDR once reading is completed
+(defvar *fixup-locations* nil)
+
+(defun fixup-backrefs ()
+  (while *fixup-locations*
+    (let* ((fixup (pop *fixup-locations*))
+           (callable (car fixup))
+           (cell (find-labelled-object (cdr fixup))))
+      (if cell
+          (funcall callable (cdr cell))
+          (error "Internal error in fixup-backrefs: object #~S# not found"
+                 (cdr fixup))))))
+
+;; A function that will need to return a fixup callback
+;; for the object that is being read. The returned callback will
+;; be called with the result of reading.
+(defvar *make-fixup-function*
+  (lambda ()
+    (error "Internal error in fixup creation during read")))
+
 (defun make-string-stream (string)
   (cons string 0))
 
@@ -88,30 +136,55 @@
       (skip-whitespaces stream)
       (setq ch (%peek-char stream)))))
 
-(defun %read-list (stream)
+(defun discard-char (stream expected)
+  (let ((ch (%read-char stream)))
+    (when (null ch)
+      (error "End of file when character ~S was expected." expected))
+    (unless (char= ch expected)
+      (error "Character ~S was found but ~S was expected." ch expected))))
+
+(defun %read-list (stream &optional (eof-error-p t) eof-value)
   (skip-whitespaces-and-comments stream)
   (let ((ch (%peek-char stream)))
     (cond
       ((null ch)
        (error "Unspected EOF"))
       ((char= ch #\))
-       (%read-char stream)
+       (discard-char stream #\))
        nil)
       (t
-       (let ((car (ls-read-1 stream)))
+       (let* ((cell (cons nil nil))
+              (*make-fixup-function* (lambda ()
+                                       (lambda (obj)
+                                         (rplaca cell obj))))
+              (eof (gensym))
+              (next (ls-read stream nil eof t)))
+         (rplaca cell next)
          (skip-whitespaces-and-comments stream)
-         (cons car
-               (if (char= (%peek-char stream) #\.)
-                   (progn
-                     (%read-char stream)
-                     (if (terminalp (%peek-char stream))
-                         (ls-read-1 stream) ; Dotted pair notation
-                         (cons (let ((string (concat "." (read-escaped-until stream #'terminalp))))
-                                 (or (values (!parse-integer string nil))
-                                     (read-float string)
-                                     (read-symbol string)))
-                               (%read-list stream))))
-                   (%read-list stream))))))))
+         (cond
+           ((eq next eof)
+            (discard-char stream #\))
+            nil)
+           (t
+            (if (char= (%peek-char stream) #\.)
+                (progn
+                  (discard-char stream #\.)
+                  (if (terminalp (%peek-char stream))
+                      (let ((*make-fixup-function* (lambda ()
+                                                     (lambda (obj)
+                                                       (rplacd cell obj)))))
+                        ;; Dotted pair notation
+                        (rplacd cell (ls-read stream eof-error-p eof-value t))
+                        (skip-whitespaces-and-comments stream)
+                        (let ((ch (%peek-char stream)))
+                          (if (or (null ch) (char= #\) ch))
+                              (discard-char stream #\))
+                              (error "Multiple objects following . in a list"))))
+                      (let ((token (concat "." (read-escaped-until stream #'terminalp))))
+                        (rplacd cell (cons (interpret-token token)
+                                           (%read-list stream eof-error-p eof-value))))))
+                (rplacd cell (%read-list stream eof-error-p eof-value)))
+            cell)))))))
 
 (defun read-string (stream)
   (let ((string "")
@@ -126,47 +199,109 @@
       (setq ch (%read-char stream)))
     string))
 
-(defun read-sharp (stream)
+(defun read-sharp (stream &optional eof-error-p eof-value)
   (%read-char stream)
-  (ecase (%read-char stream)
-    (#\'
-     (list 'function (ls-read-1 stream)))
-    (#\( (list-to-vector (%read-list stream)))
-    (#\: (make-symbol (string-upcase (read-until stream #'terminalp))))
-    (#\\
-     (let ((cname
-            (concat (string (%read-char stream))
-                    (read-until stream #'terminalp))))
+  (let ((ch (%read-char stream)))
+    (case ch
+      (#\'
+       (list 'function (ls-read stream eof-error-p eof-value t)))
+      (#\(
+       (do ((elements nil)
+            (result nil)
+            (index 0 (1+ index)))
+           ((progn (skip-whitespaces-and-comments stream)
+                   (or (null (%peek-char stream))
+                       (char= (%peek-char stream) #\))))
+            (discard-char stream #\))
+            (setf result (make-array index))
+            (dotimes (i index)
+              (aset result (decf index) (pop elements)))
+            result)
+         (let* ((ix index) ; Can't just use index: the same var would be captured in all fixups
+                (*make-fixup-function* (lambda ()
+                                         (lambda (obj)
+                                           (aset result ix obj))))
+                (eof (gensym))
+                (value (ls-read stream nil eof t)))
+           (push value elements))))
+      (#\:
+       (make-symbol
+        (unescape-token
+         (string-upcase-noescaped
+          (read-escaped-until stream #'terminalp)))))
+      (#\\
+       (let ((cname
+              (concat (string (%read-char stream))
+                      (read-until stream #'terminalp))))
+         (cond
+           ((string= cname "space") #\space)
+           ((string= cname "tab") #\tab)
+           ((string= cname "newline") #\newline)
+           (t (char cname 0)))))
+      ((#\+ #\-)
+       (let ((feature (let ((symbol (ls-read stream eof-error-p eof-value t)))
+                        (unless (symbolp symbol)
+                          (error "Invalid feature ~S" symbol))
+                        (intern (string symbol) "KEYWORD"))))
+         (if (eql (char= ch #\+)
+                  (and (find feature *features*) t))
+             (ls-read stream eof-error-p eof-value t)
+             (prog2 (ls-read stream)
+                 (ls-read stream eof-error-p eof-value t)))))
+      ((#\J #\j)
+       (unless (char= (%peek-char stream) #\:)
+         (error "FFI descriptor must start with a semicolon."))
+       (let ((descriptor (subseq (read-until stream #'terminalp) 1))
+             (subdescriptors nil))
+         (do* ((start 0 (1+ end))
+               (end (position #\: descriptor :start start)
+                    (position #\: descriptor :start start)))
+              ((null end)
+               (push (subseq descriptor start) subdescriptors)
+               `(oget *root* ,@(reverse subdescriptors)))
+           (push (subseq descriptor start end) subdescriptors))))
+      (otherwise
        (cond
-         ((string= cname "space") #\space)
-         ((string= cname "tab") #\tab)
-         ((string= cname "newline") #\newline)
-         (t (char cname 0)))))
-    (#\+
-     (let ((feature (read-until stream #'terminalp)))
-       (cond
-         ((string= feature "common-lisp")
-          (ls-read-1 stream)              ;ignore
-          (ls-read-1 stream))
-         ((string= feature "jscl")
-          (ls-read-1 stream))
+         ((and ch (digit-char-p ch))
+          (let ((id (digit-char-p ch)))
+            (while (and (%peek-char stream)
+                        (digit-char-p (%peek-char stream)))
+              (setf id (+ (* id 10) (digit-char-p (%read-char stream)))))
+            (ecase (%peek-char stream)
+              (#\=
+               (%read-char stream)
+               (if (find-labelled-object id)
+                   (error "Duplicated label #~S=" id)
+                   (progn
+                     (add-labelled-object id *future-value*)
+                     (let ((obj (ls-read stream eof-error-p eof-value t)))
+                       ;; FIXME: somehow the more natural
+                       ;;    (setf (cdr (find-labelled-object id)) obj)
+                       ;; doesn't work
+                       (rplacd (find-labelled-object id) obj)
+                       obj))))
+              (#\#
+               (%read-char stream)
+               (let ((cell (find-labelled-object id)))
+                 (if cell
+                     (if (eq (cdr cell) *future-value*)
+                         (progn
+                           (push (cons (funcall *make-fixup-function*)
+                                       id)
+                                 *fixup-locations*)
+                           *fixup-value*)
+                         (cdr cell))
+                     (error "Invalid labelled object #~S#" id)))))))
          (t
-          (error "Unknown reader form.")))))))
+          (error "Invalid dispatch character after #")))))))
 
-(defun unescape (x)
+(defun unescape-token (x)
   (let ((result ""))
     (dotimes (i (length x))
       (unless (char= (char x i) #\\)
         (setq result (concat result (string (char x i))))))
     result))
 
-(defun escape-all (x)
-  (let ((result ""))
-    (dotimes (i (length x))
-      (setq result (concat result "\\"))
-      (setq result (concat result (string (char x i)))))
-    result))
-
 (defun string-upcase-noescaped (s)
   (let ((result "")
         (last-escape nil))
@@ -198,7 +333,7 @@
       ;; No package prefix
       ((= index size)
        (setq name string)
-       (setq package *package*)
+       (setq package (package-name *package*))
        (setq internalp t))
       (t
        ;; Package prefix
@@ -211,8 +346,8 @@
          (incf index))
        (setq name (subseq string index))))
     ;; Canonalize symbol name and package
-    (setq name (if (equal package "JS")
-                   (setq name (unescape name))
+    (setq name (if (string= package "JS")
+                   (setq name (unescape-token name))
                    (setq name (string-upcase-noescaped name))))
     (setq package (find-package package))
     (if (or internalp
@@ -289,8 +424,7 @@
       ;; Optional exponent part
       (when (< index size)
         ;; Exponent-marker
-        (unless (member (string-upcase (string (char string index)))
-                        '("E" "S" "F" "D" "L"))
+        (unless (find (char-upcase (char string index)) "ESFDL")
           (return))
         (incf index)
         (unless (< index size) (return))
@@ -310,7 +444,7 @@
       (unless (= index size) (return))
       ;; Everything went ok, we have a float
       ;; XXX: Use FLOAT when implemented.
-      (/ (* sign (expt 10.0 (* exponent-sign exponent)) number) divisor))))
+      (/ (* sign (expt 10.0 (* exponent-sign exponent)) number) divisor 1.0))))
 
 (defun !parse-integer (string junk-allow)
   (block nil
@@ -356,45 +490,54 @@
         (values num index)
         (error "Junk detected."))))
 
-(defvar *eof* (gensym))
-(defun ls-read-1 (stream)
-  (skip-whitespaces-and-comments stream)
-  (let ((ch (%peek-char stream)))
-    (cond
-      ((or (null ch) (char= ch #\)))
-       *eof*)
-      ((char= ch #\()
-       (%read-char stream)
-       (%read-list stream))
-      ((char= ch #\')
-       (%read-char stream)
-       (list 'quote (ls-read-1 stream)))
-      ((char= ch #\`)
-       (%read-char stream)
-       (list 'backquote (ls-read-1 stream)))
-      ((char= ch #\")
-       (%read-char stream)
-       (read-string stream))
-      ((char= ch #\,)
-       (%read-char stream)
-       (if (eql (%peek-char stream) #\@)
-           (progn (%read-char stream) (list 'unquote-splicing (ls-read-1 stream)))
-           (list 'unquote (ls-read-1 stream))))
-      ((char= ch #\#)
-       (read-sharp stream))
-      (t
-       (let ((string (read-escaped-until stream #'terminalp)))
-         (or (read-integer string)
-             (read-float string)
-             (read-symbol string)))))))
-
-(defun ls-read (stream &optional (eof-error-p t) eof-value)
-  (let ((x (ls-read-1 stream)))
-    (if (eq x *eof*)
-        (if eof-error-p
-            (error "End of file")
-            eof-value)
-        x)))
+
+(defun interpret-token (string)
+  (or (read-integer string)
+      (read-float string)
+      (read-symbol string)))
+
+(defun ls-read (stream &optional (eof-error-p t) eof-value recursive-p)
+  (let ((save-labelled-objects *labelled-objects*)
+        (save-fixup-locations *fixup-locations*))
+    (unless recursive-p
+      (setf *fixup-locations* nil)
+      (setf *labelled-objects* (new-labelled-objects-table)))
+    (prog1
+        (progn
+          (skip-whitespaces-and-comments stream)
+          (let ((ch (%peek-char stream)))
+            (cond
+              ((or (null ch) (char= ch #\)))
+               (if eof-error-p
+                   (error "End of file")
+                   eof-value))
+              ((char= ch #\()
+               (%read-char stream)
+               (%read-list stream eof-error-p eof-value))
+              ((char= ch #\')
+               (%read-char stream)
+               (list 'quote (ls-read stream eof-error-p eof-value t)))
+              ((char= ch #\`)
+               (%read-char stream)
+               (list 'backquote (ls-read stream eof-error-p eof-value t)))
+              ((char= ch #\")
+               (%read-char stream)
+               (read-string stream))
+              ((char= ch #\,)
+               (%read-char stream)
+               (if (eql (%peek-char stream) #\@)
+                   (progn (%read-char stream) (list 'unquote-splicing
+                                                    (ls-read stream eof-error-p eof-value t)))
+                   (list 'unquote (ls-read stream eof-error-p eof-value t))))
+              ((char= ch #\#)
+               (read-sharp stream eof-error-p eof-value))
+              (t
+               (let ((string (read-escaped-until stream #'terminalp)))
+                 (interpret-token string))))))
+      (unless recursive-p
+        (fixup-backrefs)
+        (setf *labelled-objects* save-labelled-objects)
+        (setf *fixup-locations* save-fixup-locations)))))
 
 (defun ls-read-from-string (string &optional (eof-error-p t) eof-value)
   (ls-read (make-string-stream string) eof-error-p eof-value))