sql/oodml.lisp

   1 ;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10 -*-
   2 ;;;; *************************************************************************
   3 ;;;;
   4 ;;;; $Id$
   5 ;;;;
   6 ;;;; The CLSQL Object Oriented Data Manipulation Language (OODML).
   7 ;;;;
   8 ;;;; This file is part of CLSQL.
   9 ;;;;
  10 ;;;; CLSQL users are granted the rights to distribute and use this software
  11 ;;;; as governed by the terms of the Lisp Lesser GNU Public License
  12 ;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
  13 ;;;; *************************************************************************
  14
  15 (in-package #:clsql-sys)
  16
  17
  18 (defun key-qualifier-for-instance (obj &key (database *default-database*))
  19   (let ((tb (view-table (class-of obj))))
  20     (flet ((qfk (k)
  21              (sql-operation '==
  22                             (sql-expression :attribute
  23                                             (view-class-slot-column k)
  24                                             :table tb)
  25                             (db-value-from-slot
  26                              k
  27                              (slot-value obj (slot-definition-name k))
  28                              database))))
  29       (let* ((keys (keyslots-for-class (class-of obj)))
  30              (keyxprs (mapcar #'qfk (reverse keys))))
  31         (cond
  32           ((= (length keyxprs) 0) nil)
  33           ((= (length keyxprs) 1) (car keyxprs))
  34           ((> (length keyxprs) 1) (apply #'sql-operation 'and keyxprs)))))))
  35
  36 ;;
  37 ;; Function used by 'generate-selection-list'
  38 ;;
  39
  40 (defun generate-attribute-reference (vclass slotdef)
  41   (cond
  42    ((eq (view-class-slot-db-kind slotdef) :base)
  43     (sql-expression :attribute (view-class-slot-column slotdef)
  44                     :table (view-table vclass)))
  45    ((eq (view-class-slot-db-kind slotdef) :key)
  46     (sql-expression :attribute (view-class-slot-column slotdef)
  47                     :table (view-table vclass)))
  48    (t nil)))
  49
  50 ;;
  51 ;; Function used by 'find-all'
  52 ;;
  53
  54 (defun generate-selection-list (vclass)
  55   (let ((sels nil))
  56     (dolist (slotdef (ordered-class-slots vclass))
  57       (let ((res (generate-attribute-reference vclass slotdef)))
  58         (when res
  59           (push (cons slotdef res) sels))))
  60     (if sels
  61         sels
  62         (error "No slots of type :base in view-class ~A" (class-name vclass)))))
  63
  64
  65
  66 (defun generate-retrieval-joins-list (vclass retrieval-method)
  67   "Returns list of immediate join slots for a class."
  68   (let ((join-slotdefs nil))
  69     (dolist (slotdef (ordered-class-slots vclass) join-slotdefs)
  70       (when (and (eq :join (view-class-slot-db-kind slotdef))
  71                  (eq retrieval-method (gethash :retrieval (view-class-slot-db-info slotdef))))
  72         (push slotdef join-slotdefs)))))
  73
  74 (defun generate-immediate-joins-selection-list (vclass)
  75   "Returns list of immediate join slots for a class."
  76   (let (sels)
  77     (dolist (joined-slot (generate-retrieval-joins-list vclass :immediate) sels)
  78       (let* ((join-class-name (gethash :join-class (view-class-slot-db-info joined-slot)))
  79              (join-class (when join-class-name (find-class join-class-name))))
  80         (dolist (slotdef (ordered-class-slots join-class))
  81           (let ((res (generate-attribute-reference join-class slotdef)))
  82             (when res
  83               (push (cons slotdef res) sels))))))
  84     sels))
  85
  86
  87 ;; Called by 'get-slot-values-from-view'
  88 ;;
  89
  90 (defmethod update-slot-from-db ((instance standard-db-object) slotdef value)
  91   (declare (optimize (speed 3) #+cmu (extensions:inhibit-warnings 3)))
  92   (let* ((slot-reader (view-class-slot-db-reader slotdef))
  93          (slot-name   (slot-definition-name slotdef))
  94          (slot-type   (specified-type slotdef)))
  95     (cond ((and value (null slot-reader))
  96            (setf (slot-value instance slot-name)
  97                  (read-sql-value value (delistify slot-type)
  98                                  (view-database instance)
  99                                  (database-underlying-type
 100                                   (view-database instance)))))
 101           ((null value)
 102            (update-slot-with-null instance slot-name slotdef))
 103           ((typep slot-reader 'string)
 104            (setf (slot-value instance slot-name)
 105                  (format nil slot-reader value)))
 106           ((typep slot-reader 'function)
 107            (setf (slot-value instance slot-name)
 108                  (apply slot-reader (list value))))
 109           (t
 110            (error "Slot reader is of an unusual type.")))))
 111
 112 (defmethod key-value-from-db (slotdef value database)
 113   (declare (optimize (speed 3) #+cmu (extensions:inhibit-warnings 3)))
 114   (let ((slot-reader (view-class-slot-db-reader slotdef))
 115         (slot-type (specified-type slotdef)))
 116     (cond ((and value (null slot-reader))
 117            (read-sql-value value (delistify slot-type) database
 118                            (database-underlying-type database)))
 119           ((null value)
 120            nil)
 121           ((typep slot-reader 'string)
 122            (format nil slot-reader value))
 123           ((typep slot-reader 'function)
 124            (apply slot-reader (list value)))
 125           (t
 126            (error "Slot reader is of an unusual type.")))))
 127
 128 (defun db-value-from-slot (slotdef val database)
 129   (let ((dbwriter (view-class-slot-db-writer slotdef))
 130         (dbtype (specified-type slotdef)))
 131     (typecase dbwriter
 132       (string (format nil dbwriter val))
 133       (function (apply dbwriter (list val)))
 134       (t
 135        (database-output-sql-as-type
 136         (typecase dbtype
 137           (cons (car dbtype))
 138           (t dbtype))
 139         val database (database-underlying-type database))))))
 140
 141 (defun check-slot-type (slotdef val)
 142   (let* ((slot-type (specified-type slotdef))
 143          (basetype (if (listp slot-type) (car slot-type) slot-type)))
 144     (when (and slot-type val)
 145       (unless (typep val basetype)
 146         (error 'sql-user-error
 147                :message
 148                (format nil "Invalid value ~A in slot ~A, not of type ~A."
 149                        val (slot-definition-name slotdef) slot-type))))))
 150
 151 ;;
 152 ;; Called by find-all
 153 ;;
 154
 155 (defmethod get-slot-values-from-view (obj slotdeflist values)
 156     (flet ((update-slot (slot-def values)
 157              (update-slot-from-db obj slot-def values)))
 158       (mapc #'update-slot slotdeflist values)
 159       obj))
 160
 161 (defmethod update-record-from-slot ((obj standard-db-object) slot &key
 162                                     (database *default-database*))
 163   (let* ((database (or (view-database obj) database))
 164          (vct (view-table (class-of obj)))
 165          (sd (slotdef-for-slot-with-class slot (class-of obj))))
 166     (check-slot-type sd (slot-value obj slot))
 167     (let* ((att (view-class-slot-column sd))
 168            (val (db-value-from-slot sd (slot-value obj slot) database)))
 169       (cond ((and vct sd (view-database obj))
 170              (update-records (sql-expression :table vct)
 171                              :attributes (list (sql-expression :attribute att))
 172                              :values (list val)
 173                              :where (key-qualifier-for-instance
 174                                      obj :database database)
 175                              :database database))
 176             ((and vct sd (not (view-database obj)))
 177              (insert-records :into (sql-expression :table vct)
 178                              :attributes (list (sql-expression :attribute att))
 179                              :values (list val)
 180                              :database database)
 181              (setf (slot-value obj 'view-database) database))
 182             (t
 183              (error "Unable to update record.")))))
 184   (values))
 185
 186 (defmethod update-record-from-slots ((obj standard-db-object) slots &key
 187                                      (database *default-database*))
 188   (let* ((database (or (view-database obj) database))
 189          (vct (view-table (class-of obj)))
 190          (sds (slotdefs-for-slots-with-class slots (class-of obj)))
 191          (avps (mapcar #'(lambda (s)
 192                            (let ((val (slot-value
 193                                        obj (slot-definition-name s))))
 194                              (check-slot-type s val)
 195                              (list (sql-expression
 196                                     :attribute (view-class-slot-column s))
 197                                    (db-value-from-slot s val database))))
 198                        sds)))
 199     (cond ((and avps (view-database obj))
 200            (update-records (sql-expression :table vct)
 201                            :av-pairs avps
 202                            :where (key-qualifier-for-instance
 203                                    obj :database database)
 204                            :database database))
 205           ((and avps (not (view-database obj)))
 206            (insert-records :into (sql-expression :table vct)
 207                            :av-pairs avps
 208                            :database database)
 209            (setf (slot-value obj 'view-database) database))
 210           (t
 211            (error "Unable to update records"))))
 212   (values))
 213
 214 (defmethod update-records-from-instance ((obj standard-db-object) &key database)
 215   (let ((database (or database (view-database obj) *default-database*)))
 216     (labels ((slot-storedp (slot)
 217                (and (member (view-class-slot-db-kind slot) '(:base :key))
 218                     (slot-boundp obj (slot-definition-name slot))))
 219              (slot-value-list (slot)
 220                (let ((value (slot-value obj (slot-definition-name slot))))
 221                  (check-slot-type slot value)
 222                  (list (sql-expression :attribute (view-class-slot-column slot))
 223                        (db-value-from-slot slot value database)))))
 224       (let* ((view-class (class-of obj))
 225              (view-class-table (view-table view-class))
 226              (slots (remove-if-not #'slot-storedp
 227                                    (ordered-class-slots view-class)))
 228              (record-values (mapcar #'slot-value-list slots)))
 229         (unless record-values
 230           (error "No settable slots."))
 231         (if (view-database obj)
 232             (update-records (sql-expression :table view-class-table)
 233                             :av-pairs record-values
 234                             :where (key-qualifier-for-instance
 235                                     obj :database database)
 236                             :database database)
 237             (progn
 238               (insert-records :into (sql-expression :table view-class-table)
 239                               :av-pairs record-values
 240                               :database database)
 241               (setf (slot-value obj 'view-database) database))))))
 242   (values))
 243
 244 (defmethod delete-instance-records ((instance standard-db-object))
 245   (let ((vt (sql-expression :table (view-table (class-of instance))))
 246         (vd (view-database instance)))
 247     (if vd
 248         (let ((qualifier (key-qualifier-for-instance instance :database vd)))
 249           (delete-records :from vt :where qualifier :database vd)
 250           (setf (record-caches vd) nil)
 251           (setf (slot-value instance 'view-database) nil)
 252           (values))
 253         (signal-no-database-error vd))))
 254
 255 (defmethod update-instance-from-records ((instance standard-db-object)
 256                                          &key (database *default-database*))
 257   (let* ((view-class (find-class (class-name (class-of instance))))
 258          (view-table (sql-expression :table (view-table view-class)))
 259          (vd (or (view-database instance) database))
 260          (view-qual (key-qualifier-for-instance instance :database vd))
 261          (sels (generate-selection-list view-class))
 262          (res (apply #'select (append (mapcar #'cdr sels)
 263                                       (list :from  view-table
 264                                             :where view-qual)
 265                                       (list :result-types nil)))))
 266     (when res
 267       (get-slot-values-from-view instance (mapcar #'car sels) (car res)))))
 268
 269 (defmethod update-slot-from-record ((instance standard-db-object)
 270                                     slot &key (database *default-database*))
 271   (let* ((view-class (find-class (class-name (class-of instance))))
 272          (view-table (sql-expression :table (view-table view-class)))
 273          (vd (or (view-database instance) database))
 274          (view-qual (key-qualifier-for-instance instance :database vd))
 275          (slot-def (slotdef-for-slot-with-class slot view-class))
 276          (att-ref (generate-attribute-reference view-class slot-def))
 277          (res (select att-ref :from  view-table :where view-qual
 278                       :result-types nil)))
 279     (when res
 280       (get-slot-values-from-view instance (list slot-def) (car res)))))
 281
 282
 283 (defmethod update-slot-with-null ((object standard-db-object)
 284                                   slotname
 285                                   slotdef)
 286   (setf (slot-value object slotname) (slot-value slotdef 'void-value)))
 287
 288 (defvar +no-slot-value+ '+no-slot-value+)
 289
 290 (defsql sql-slot-value (:symbol "slot-value") (classname slot &optional (value +no-slot-value+) (database *default-database*))
 291   (let* ((class (find-class classname))
 292          (sld (slotdef-for-slot-with-class slot class)))
 293     (if sld
 294         (if (eq value +no-slot-value+)
 295             (sql-expression :attribute (view-class-slot-column sld)
 296                             :table (view-table class))
 297             (db-value-from-slot
 298              sld
 299              value
 300              database))
 301         (error "Unknown slot ~A for class ~A" slot classname))))
 302
 303 (defsql sql-view-class (:symbol "view-class") (classname &optional (database *default-database*))
 304         (declare (ignore database))
 305         (let* ((class (find-class classname)))
 306           (unless (view-table class)
 307             (error "No view-table for class ~A"  classname))
 308           (sql-expression :table (view-table class))))
 309
 310
 311 (defmethod database-get-type-specifier (type args database db-type)
 312   (declare (ignore type args database db-type))
 313   (format nil "VARCHAR(~D)" *default-string-length*))
 314
 315 (defmethod database-get-type-specifier ((type (eql 'integer)) args database db-type)
 316   (declare (ignore database db-type))
 317   (if args
 318       (format nil "INT(~A)" (car args))
 319     "INT"))
 320
 321 (deftype tinyint ()
 322   "An 8-bit integer, this width may vary by SQL implementation."
 323   'integer)
 324
 325 (defmethod database-get-type-specifier ((type (eql 'tinyint)) args database db-type)
 326   (declare (ignore args database db-type))
 327   "INT")
 328
 329 (deftype smallint ()
 330   "An integer smaller than a 32-bit integer. this width may vary by SQL implementation."
 331   'integer)
 332
 333 (defmethod database-get-type-specifier ((type (eql 'smallint)) args database db-type)
 334   (declare (ignore args database db-type))
 335   "INT")
 336
 337 (deftype mediumint ()
 338   "An integer smaller than a 32-bit integer, but may be larger than a smallint. This width may vary by SQL implementation."
 339   'integer)
 340
 341 (defmethod database-get-type-specifier ((type (eql 'mediumint)) args database db-type)
 342   (declare (ignore args database db-type))
 343   "INT")
 344
 345 (deftype bigint ()
 346   "An integer larger than a 32-bit integer, this width may vary by SQL implementation."
 347   'integer)
 348
 349 (defmethod database-get-type-specifier ((type (eql 'bigint)) args database db-type)
 350   (declare (ignore args database db-type))
 351   "BIGINT")
 352
 353 (deftype varchar (&optional size)
 354   "A variable length string for the SQL varchar type."
 355   (declare (ignore size))
 356   'string)
 357
 358 (defmethod database-get-type-specifier ((type (eql 'varchar)) args
 359                                         database db-type)
 360   (declare (ignore database db-type))
 361   (if args
 362       (format nil "VARCHAR(~A)" (car args))
 363       (format nil "VARCHAR(~D)" *default-string-length*)))
 364
 365 (defmethod database-get-type-specifier ((type (eql 'string)) args database db-type)
 366   (declare (ignore database db-type))
 367   (if args
 368       (format nil "CHAR(~A)" (car args))
 369       (format nil "VARCHAR(~D)" *default-string-length*)))
 370
 371 (deftype universal-time ()
 372   "A positive integer as returned by GET-UNIVERSAL-TIME."
 373   '(integer 1 *))
 374
 375 (defmethod database-get-type-specifier ((type (eql 'universal-time)) args database db-type)
 376   (declare (ignore args database db-type))
 377   "BIGINT")
 378
 379 (defmethod database-get-type-specifier ((type (eql 'wall-time)) args database db-type)
 380   (declare (ignore args database db-type))
 381   "TIMESTAMP")
 382
 383 (defmethod database-get-type-specifier ((type (eql 'duration)) args database db-type)
 384   (declare (ignore database args db-type))
 385   "VARCHAR")
 386
 387 (defmethod database-get-type-specifier ((type (eql 'money)) args database db-type)
 388   (declare (ignore database args db-type))
 389   "INT8")
 390
 391 #+ignore
 392 (deftype char (&optional len)
 393   "A lisp type for the SQL CHAR type."
 394   `(string ,len))
 395
 396 (defmethod database-get-type-specifier ((type (eql 'float)) args database db-type)
 397   (declare (ignore database db-type))
 398   (if args
 399       (format nil "FLOAT(~A)" (car args))
 400       "FLOAT"))
 401
 402 (defmethod database-get-type-specifier ((type (eql 'long-float)) args database db-type)
 403   (declare (ignore database db-type))
 404   (if args
 405       (format nil "FLOAT(~A)" (car args))
 406       "FLOAT"))
 407
 408 (deftype generalized-boolean ()
 409   "A type which outputs a SQL boolean value, though any lisp type can be stored in the slot."
 410   t)
 411
 412 (defmethod database-get-type-specifier ((type (eql 'boolean)) args database db-type)
 413   (declare (ignore args database db-type))
 414   "BOOL")
 415
 416 (defmethod database-get-type-specifier ((type (eql 'generalized-boolean)) args database db-type)
 417   (declare (ignore args database db-type))
 418   "BOOL")
 419
 420 (defmethod database-get-type-specifier ((type (eql 'number)) args database db-type)
 421   (declare (ignore database db-type))
 422   (cond
 423    ((and (consp args) (= (length args) 2))
 424     (format nil "NUMBER(~D,~D)" (first args) (second args)))
 425    ((and (consp args) (= (length args) 1))
 426     (format nil "NUMBER(~D)" (first args)))
 427    (t
 428     "NUMBER")))
 429
 430 (defmethod database-get-type-specifier ((type (eql 'char)) args database db-type)
 431   (declare (ignore database db-type))
 432   (if args
 433       (format nil "CHAR(~D)" (first args))
 434       "CHAR(1)"))
 435
 436
 437 (defmethod database-output-sql-as-type (type val database db-type)
 438   (declare (ignore type database db-type))
 439   val)
 440
 441 (defmethod database-output-sql-as-type ((type (eql 'list)) val database db-type)
 442   (declare (ignore database db-type))
 443   (progv '(*print-circle* *print-array*) '(t t)
 444     (let ((escaped (prin1-to-string val)))
 445       (substitute-char-string
 446        escaped #\Null " "))))
 447
 448 (defmethod database-output-sql-as-type ((type (eql 'symbol)) val database db-type)
 449   (declare (ignore database db-type))
 450   (if val
 451     (concatenate 'string
 452                  (package-name (symbol-package val))
 453                  "::"
 454                  (symbol-name val))
 455     ""))
 456
 457 (defmethod database-output-sql-as-type ((type (eql 'keyword)) val database db-type)
 458   (declare (ignore database db-type))
 459   (if val
 460       (symbol-name val)
 461       ""))
 462
 463 (defmethod database-output-sql-as-type ((type (eql 'vector)) val database db-type)
 464   (declare (ignore database db-type))
 465   (progv '(*print-circle* *print-array*) '(t t)
 466     (prin1-to-string val)))
 467
 468 (defmethod database-output-sql-as-type ((type (eql 'array)) val database db-type)
 469   (declare (ignore database db-type))
 470   (progv '(*print-circle* *print-array*) '(t t)
 471     (prin1-to-string val)))
 472
 473 (defmethod database-output-sql-as-type ((type (eql 'boolean)) val database db-type)
 474   (declare (ignore database db-type))
 475   (if val "t" "f"))
 476
 477 (defmethod database-output-sql-as-type ((type (eql 'generalized-boolean)) val database db-type)
 478   (declare (ignore database db-type))
 479   (if val "t" "f"))
 480
 481 (defmethod database-output-sql-as-type ((type (eql 'string)) val database db-type)
 482   (declare (ignore database db-type))
 483   val)
 484
 485 (defmethod database-output-sql-as-type ((type (eql 'char)) val database db-type)
 486   (declare (ignore database db-type))
 487   (etypecase val
 488     (character (write-to-string val))
 489     (string val)))
 490
 491 (defmethod database-output-sql-as-type ((type (eql 'float)) val database db-type)
 492   (declare (ignore database db-type))
 493   (let ((*read-default-float-format* (type-of val)))
 494     (format nil "~F" val)))
 495
 496 (defmethod read-sql-value (val type database db-type)
 497   (declare (ignore type database db-type))
 498   (read-from-string val))
 499
 500 (defmethod read-sql-value (val (type (eql 'string)) database db-type)
 501   (declare (ignore database db-type))
 502   val)
 503
 504 (defmethod read-sql-value (val (type (eql 'varchar)) database db-type)
 505   (declare (ignore database db-type))
 506   val)
 507
 508 (defmethod read-sql-value (val (type (eql 'char)) database db-type)
 509   (declare (ignore database db-type))
 510   (schar val 0))
 511
 512 (defmethod read-sql-value (val (type (eql 'keyword)) database db-type)
 513   (declare (ignore database db-type))
 514   (when (< 0 (length val))
 515     (intern (symbol-name-default-case val)
 516             (find-package '#:keyword))))
 517
 518 (defmethod read-sql-value (val (type (eql 'symbol)) database db-type)
 519   (declare (ignore database db-type))
 520   (when (< 0 (length val))
 521     (unless (string= val (symbol-name-default-case "NIL"))
 522       (read-from-string val))))
 523
 524 (defmethod read-sql-value (val (type (eql 'integer)) database db-type)
 525   (declare (ignore database db-type))
 526   (etypecase val
 527     (string
 528      (unless (string-equal "NIL" val)
 529        (parse-integer val)))
 530     (number val)))
 531
 532 (defmethod read-sql-value (val (type (eql 'smallint)) database db-type)
 533   (declare (ignore database db-type))
 534   (etypecase val
 535     (string
 536      (unless (string-equal "NIL" val)
 537        (parse-integer val)))
 538     (number val)))
 539
 540 (defmethod read-sql-value (val (type (eql 'bigint)) database db-type)
 541   (declare (ignore database db-type))
 542   (etypecase val
 543     (string
 544      (unless (string-equal "NIL" val)
 545        (parse-integer val)))
 546     (number val)))
 547
 548 (defmethod read-sql-value (val (type (eql 'float)) database db-type)
 549   (declare (ignore database db-type))
 550   ;; writing 1.0 writes 1, so we we *really* want a float, must do (float ...)
 551   (etypecase val
 552     (string
 553      (float (read-from-string val)))
 554     (float
 555      val)))
 556
 557 (defmethod read-sql-value (val (type (eql 'boolean)) database db-type)
 558   (declare (ignore database db-type))
 559   (equal "t" val))
 560
 561 (defmethod read-sql-value (val (type (eql 'generalized-boolean)) database db-type)
 562   (declare (ignore database db-type))
 563   (equal "t" val))
 564
 565 (defmethod read-sql-value (val (type (eql 'number)) database db-type)
 566   (declare (ignore database db-type))
 567   (etypecase val
 568     (string
 569      (unless (string-equal "NIL" val)
 570        (read-from-string val)))
 571     (number val)))
 572
 573 (defmethod read-sql-value (val (type (eql 'universal-time)) database db-type)
 574   (declare (ignore database db-type))
 575   (unless (eq 'NULL val)
 576     (etypecase val
 577       (string
 578        (parse-integer val))
 579       (number val))))
 580
 581 (defmethod read-sql-value (val (type (eql 'wall-time)) database db-type)
 582   (declare (ignore database db-type))
 583   (unless (eq 'NULL val)
 584     (parse-timestring val)))
 585
 586 (defmethod read-sql-value (val (type (eql 'duration)) database db-type)
 587   (declare (ignore database db-type))
 588   (unless (or (eq 'NULL val)
 589               (equal "NIL" val))
 590     (parse-timestring val)))
 591
 592 ;; ------------------------------------------------------------
 593 ;; Logic for 'faulting in' :join slots
 594
 595 ;; this works, but is inefficient requiring (+ 1 n-rows)
 596 ;; SQL queries
 597 #+ignore
 598 (defun fault-join-target-slot (class object slot-def)
 599   (let* ((res (fault-join-slot-raw class object slot-def))
 600          (dbi (view-class-slot-db-info slot-def))
 601          (target-name (gethash :target-slot dbi))
 602          (target-class (find-class target-name)))
 603     (when res
 604       (mapcar (lambda (obj)
 605                 (list
 606                  (car
 607                   (fault-join-slot-raw
 608                    target-class
 609                    obj
 610                    (find target-name (class-slots (class-of obj))
 611                          :key #'slot-definition-name)))
 612                  obj))
 613               res)
 614       #+ignore ;; this doesn't work when attempting to call slot-value
 615       (mapcar (lambda (obj)
 616                 (cons obj (slot-value obj ts))) res))))
 617
 618 (defun fault-join-target-slot (class object slot-def)
 619   (let* ((dbi (view-class-slot-db-info slot-def))
 620          (ts (gethash :target-slot dbi))
 621          (jc (gethash :join-class dbi))
 622          (ts-view-table (view-table (find-class ts)))
 623          (jc-view-table (view-table (find-class jc)))
 624          (tdbi (view-class-slot-db-info
 625                 (find ts (class-slots (find-class jc))
 626                       :key #'slot-definition-name)))
 627          (retrieval (gethash :retrieval tdbi))
 628          (jq (join-qualifier class object slot-def))
 629          (key (slot-value object (gethash :home-key dbi))))
 630     (when jq
 631       (ecase retrieval
 632         (:immediate
 633          (let ((res
 634                 (find-all (list ts)
 635                           :inner-join (sql-expression :table jc-view-table)
 636                           :on (sql-operation
 637                                '==
 638                                (sql-expression
 639                                 :attribute (gethash :foreign-key tdbi)
 640                                 :table ts-view-table)
 641                                (sql-expression
 642                                 :attribute (gethash :home-key tdbi)
 643                                 :table jc-view-table))
 644                           :where jq
 645                           :result-types :auto
 646                           :database (view-database object))))
 647            (mapcar #'(lambda (i)
 648                        (let* ((instance (car i))
 649                               (jcc (make-instance jc :view-database (view-database instance))))
 650                          (setf (slot-value jcc (gethash :foreign-key dbi))
 651                                key)
 652                          (setf (slot-value jcc (gethash :home-key tdbi))
 653                                (slot-value instance (gethash :foreign-key tdbi)))
 654                       (list instance jcc)))
 655                    res)))
 656         (:deferred
 657             ;; just fill in minimal slots
 658             (mapcar
 659              #'(lambda (k)
 660                  (let ((instance (make-instance ts :view-database (view-database object)))
 661                        (jcc (make-instance jc :view-database (view-database object)))
 662                        (fk (car k)))
 663                    (setf (slot-value instance (gethash :home-key tdbi)) fk)
 664                    (setf (slot-value jcc (gethash :foreign-key dbi))
 665                          key)
 666                    (setf (slot-value jcc (gethash :home-key tdbi))
 667                          fk)
 668                    (list instance jcc)))
 669              (select (sql-expression :attribute (gethash :foreign-key tdbi) :table jc-view-table)
 670                      :from (sql-expression :table jc-view-table)
 671                      :where jq
 672                      :database (view-database object))))))))
 673
 674
 675 ;;; Remote Joins
 676
 677 (defvar *default-update-objects-max-len* nil
 678   "The default value to use for the MAX-LEN keyword argument to
 679   UPDATE-OBJECT-JOINS.")
 680
 681 (defun update-objects-joins (objects &key (slots t) (force-p t)
 682                             class-name (max-len
 683                             *default-update-objects-max-len*))
 684   "Updates from the records of the appropriate database tables
 685 the join slots specified by SLOTS in the supplied list of View
 686 Class instances OBJECTS.  SLOTS is t by default which means that
 687 all join slots with :retrieval :immediate are updated. CLASS-NAME
 688 is used to specify the View Class of all instance in OBJECTS and
 689 default to nil which means that the class of the first instance
 690 in OBJECTS is used. FORCE-P is t by default which means that all
 691 join slots are updated whereas a value of nil means that only
 692 unbound join slots are updated. MAX-LEN defaults to
 693 *DEFAULT-UPDATE-OBJECTS-MAX-LEN* and when non-nil specifies that
 694 UPDATE-OBJECT-JOINS may issue multiple database queries with a
 695 maximum of MAX-LEN instances updated in each query."
 696   (assert (or (null max-len) (plusp max-len)))
 697   (when objects
 698     (unless class-name
 699       (setq class-name (class-name (class-of (first objects)))))
 700     (let* ((class (find-class class-name))
 701            (class-slots (ordered-class-slots class))
 702            (slotdefs
 703             (if (eq t slots)
 704                 (generate-retrieval-joins-list class :deferred)
 705               (remove-if #'null
 706                          (mapcar #'(lambda (name)
 707                                      (let ((slotdef (find name class-slots :key #'slot-definition-name)))
 708                                        (unless slotdef
 709                                          (warn "Unable to find slot named ~S in class ~S." name class))
 710                                        slotdef))
 711                                  slots)))))
 712       (dolist (slotdef slotdefs)
 713         (let* ((dbi (view-class-slot-db-info slotdef))
 714                (slotdef-name (slot-definition-name slotdef))
 715                (foreign-key (gethash :foreign-key dbi))
 716                (home-key (gethash :home-key dbi))
 717                (object-keys
 718                 (remove-duplicates
 719                  (if force-p
 720                      (mapcar #'(lambda (o) (slot-value o home-key)) objects)
 721                    (remove-if #'null
 722                               (mapcar
 723                                #'(lambda (o) (if (slot-boundp o slotdef-name)
 724                                                  nil
 725                                                (slot-value o home-key)))
 726                                objects)))))
 727                (n-object-keys (length object-keys))
 728                (query-len (or max-len n-object-keys)))
 729
 730           (do ((i 0 (+ i query-len)))
 731               ((>= i n-object-keys))
 732             (let* ((keys (if max-len
 733                              (subseq object-keys i (min (+ i query-len) n-object-keys))
 734                            object-keys))
 735                    (results (find-all (list (gethash :join-class dbi))
 736                                       :where (make-instance 'sql-relational-exp
 737                                                :operator 'in
 738                                                :sub-expressions (list (sql-expression :attribute foreign-key)
 739                                                                       keys))
 740                                       :result-types :auto
 741                                       :flatp t)))
 742
 743               (dolist (object objects)
 744                 (when (or force-p (not (slot-boundp object slotdef-name)))
 745                   (let ((res (remove-if-not #'(lambda (obj)
 746                                                 (equal obj (slot-value
 747                                                             object
 748                                                             home-key)))
 749                                             results
 750                                             :key #'(lambda (res)
 751                                                      (slot-value res
 752                                                                  foreign-key)))))
 753                     (when res
 754                       (setf (slot-value object slotdef-name)
 755                             (if (gethash :set dbi) res (car res)))))))))))))
 756   (values))
 757
 758 (defun fault-join-slot-raw (class object slot-def)
 759   (let* ((dbi (view-class-slot-db-info slot-def))
 760          (jc (gethash :join-class dbi)))
 761     (let ((jq (join-qualifier class object slot-def)))
 762       (when jq
 763         (select jc :where jq :flatp t :result-types nil
 764                 :database (view-database object))))))
 765
 766 (defun fault-join-slot (class object slot-def)
 767   (let* ((dbi (view-class-slot-db-info slot-def))
 768          (ts (gethash :target-slot dbi)))
 769     (if (and ts (gethash :set dbi))
 770         (fault-join-target-slot class object slot-def)
 771         (let ((res (fault-join-slot-raw class object slot-def)))
 772           (when res
 773             (cond
 774               ((and ts (not (gethash :set dbi)))
 775                (mapcar (lambda (obj) (slot-value obj ts)) res))
 776               ((and (not ts) (not (gethash :set dbi)))
 777                (car res))
 778               ((and (not ts) (gethash :set dbi))
 779                res)))))))
 780
 781 (defun join-qualifier (class object slot-def)
 782     (declare (ignore class))
 783     (let* ((dbi (view-class-slot-db-info slot-def))
 784            (jc (find-class (gethash :join-class dbi)))
 785            ;;(ts (gethash :target-slot dbi))
 786            ;;(tsdef (if ts (slotdef-for-slot-with-class ts jc)))
 787            (foreign-keys (gethash :foreign-key dbi))
 788            (home-keys (gethash :home-key dbi)))
 789       (when (every #'(lambda (slt)
 790                        (and (slot-boundp object slt)
 791                             (not (null (slot-value object slt)))))
 792                    (if (listp home-keys) home-keys (list home-keys)))
 793         (let ((jc
 794                (mapcar #'(lambda (hk fk)
 795                            (let ((fksd (slotdef-for-slot-with-class fk jc)))
 796                              (sql-operation '==
 797                                             (typecase fk
 798                                               (symbol
 799                                                (sql-expression
 800                                                 :attribute
 801                                                 (view-class-slot-column fksd)
 802                                                 :table (view-table jc)))
 803                                               (t fk))
 804                                             (typecase hk
 805                                               (symbol
 806                                                (slot-value object hk))
 807                                               (t
 808                                                hk)))))
 809                        (if (listp home-keys)
 810                            home-keys
 811                            (list home-keys))
 812                        (if (listp foreign-keys)
 813                            foreign-keys
 814                            (list foreign-keys)))))
 815           (when jc
 816             (if (> (length jc) 1)
 817                 (apply #'sql-and jc)
 818                 jc))))))
 819
 820 ;; FIXME: add retrieval immediate for efficiency
 821 ;; For example, for (select 'employee-address) in test suite =>
 822 ;; select addr.*,ea_join.* FROM addr,ea_join WHERE ea_join.aaddressid=addr.addressid\g
 823
 824 (defun build-objects (vals sclasses immediate-join-classes sels immediate-joins database refresh flatp instances)
 825   "Used by find-all to build objects."
 826   (labels ((build-object (vals vclass jclasses selects immediate-selects instance)
 827              (let* ((db-vals (butlast vals (- (list-length vals)
 828                                               (list-length selects))))
 829                     (obj (if instance instance (make-instance (class-name vclass) :view-database database)))
 830                     (join-vals (subseq vals (list-length selects)))
 831                     (joins (mapcar #'(lambda (c) (when c (make-instance c :view-database database)))
 832                                    jclasses)))
 833
 834                ;;(format t "joins: ~S~%db-vals: ~S~%join-values: ~S~%selects: ~S~%immediate-selects: ~S~%"
 835                ;;joins db-vals join-vals selects immediate-selects)
 836
 837                ;; use refresh keyword here
 838                (setf obj (get-slot-values-from-view obj (mapcar #'car selects) db-vals))
 839                (mapc #'(lambda (jo)
 840                          ;; find all immediate-select slots and join-vals for this object
 841                          (let* ((slots (class-slots (class-of jo)))
 842                                 (pos-list (remove-if #'null
 843                                                      (mapcar
 844                                                       #'(lambda (s)
 845                                                           (position s immediate-selects
 846                                                                     :key #'car
 847                                                                     :test #'eq))
 848                                                       slots))))
 849                            (get-slot-values-from-view jo
 850                                                       (mapcar #'car
 851                                                               (mapcar #'(lambda (pos)
 852                                                                           (nth pos immediate-selects))
 853                                                                       pos-list))
 854                                                       (mapcar #'(lambda (pos) (nth pos join-vals))
 855                                                               pos-list))))
 856                      joins)
 857                (mapc
 858                 #'(lambda (jc)
 859                     (let ((slot (find (class-name (class-of jc)) (class-slots vclass)
 860                                       :key #'(lambda (slot)
 861                                                (when (and (eq :join (view-class-slot-db-kind slot))
 862                                                           (eq (slot-definition-name slot)
 863                                                               (gethash :join-class (view-class-slot-db-info slot))))
 864                                                  (slot-definition-name slot))))))
 865                       (when slot
 866                         (setf (slot-value obj (slot-definition-name slot)) jc))))
 867                 joins)
 868                (when refresh (instance-refreshed obj))
 869                obj)))
 870     (let* ((objects
 871             (mapcar #'(lambda (sclass jclass sel immediate-join instance)
 872                         (prog1
 873                             (build-object vals sclass jclass sel immediate-join instance)
 874                           (setf vals (nthcdr (+ (list-length sel) (list-length immediate-join))
 875                                              vals))))
 876                     sclasses immediate-join-classes sels immediate-joins instances)))
 877       (if (and flatp (= (length sclasses) 1))
 878           (car objects)
 879         objects))))
 880
 881 (defun find-all (view-classes
 882                  &rest args
 883                  &key all set-operation distinct from where group-by having
 884                       order-by offset limit refresh flatp result-types
 885                       inner-join on
 886                       (database *default-database*)
 887                       instances)
 888   "Called by SELECT to generate object query results when the
 889   View Classes VIEW-CLASSES are passed as arguments to SELECT."
 890   (declare (ignore all set-operation group-by having offset limit inner-join on)
 891            (optimize (debug 3) (speed 1)))
 892   (flet ((ref-equal (ref1 ref2)
 893            (string= (sql-output ref1 database)
 894                     (sql-output ref2 database)))
 895          (table-sql-expr (table)
 896            (sql-expression :table (view-table table)))
 897          (tables-equal (table-a table-b)
 898            (when (and table-a table-b)
 899              (string= (string (slot-value table-a 'name))
 900                       (string (slot-value table-b 'name))))))
 901     (remf args :from)
 902     (remf args :where)
 903     (remf args :flatp)
 904     (remf args :additional-fields)
 905     (remf args :result-types)
 906     (remf args :instances)
 907     (let* ((*db-deserializing* t)
 908            (sclasses (mapcar #'find-class view-classes))
 909            (immediate-join-slots
 910             (mapcar #'(lambda (c) (generate-retrieval-joins-list c :immediate)) sclasses))
 911            (immediate-join-classes
 912             (mapcar #'(lambda (jcs)
 913                         (mapcar #'(lambda (slotdef)
 914                                     (find-class (gethash :join-class (view-class-slot-db-info slotdef))))
 915                                 jcs))
 916                     immediate-join-slots))
 917            (immediate-join-sels (mapcar #'generate-immediate-joins-selection-list sclasses))
 918            (sels (mapcar #'generate-selection-list sclasses))
 919            (fullsels (apply #'append (mapcar #'append sels immediate-join-sels)))
 920            (sel-tables (collect-table-refs where))
 921            (tables (remove-if #'null
 922                               (remove-duplicates
 923                                (append (mapcar #'table-sql-expr sclasses)
 924                                        (mapcan #'(lambda (jc-list)
 925                                                    (mapcar
 926                                                     #'(lambda (jc) (when jc (table-sql-expr jc)))
 927                                                     jc-list))
 928                                                immediate-join-classes)
 929                                        sel-tables)
 930                                :test #'tables-equal)))
 931            (order-by-slots (mapcar #'(lambda (ob) (if (atom ob) ob (car ob)))
 932                                    (listify order-by)))
 933            (join-where nil))
 934
 935
 936       ;;(format t "sclasses: ~W~%ijc: ~W~%tables: ~W~%" sclasses immediate-join-classes tables)
 937
 938       (dolist (ob order-by-slots)
 939         (when (and ob (not (member ob (mapcar #'cdr fullsels)
 940                                    :test #'ref-equal)))
 941           (setq fullsels
 942             (append fullsels (mapcar #'(lambda (att) (cons nil att))
 943                                      order-by-slots)))))
 944       (dolist (ob (listify distinct))
 945         (when (and (typep ob 'sql-ident)
 946                    (not (member ob (mapcar #'cdr fullsels)
 947                                 :test #'ref-equal)))
 948           (setq fullsels
 949               (append fullsels (mapcar #'(lambda (att) (cons nil att))
 950                                        (listify ob))))))
 951       (mapcar #'(lambda (vclass jclasses jslots)
 952                   (when jclasses
 953                     (mapcar
 954                      #'(lambda (jclass jslot)
 955                          (let ((dbi (view-class-slot-db-info jslot)))
 956                            (setq join-where
 957                              (append
 958                               (list (sql-operation '==
 959                                                    (sql-expression
 960                                                     :attribute (gethash :foreign-key dbi)
 961                                                     :table (view-table jclass))
 962                                                    (sql-expression
 963                                                     :attribute (gethash :home-key dbi)
 964                                                     :table (view-table vclass))))
 965                               (when join-where (listify join-where))))))
 966                      jclasses jslots)))
 967               sclasses immediate-join-classes immediate-join-slots)
 968       (when where
 969         (setq where (listify where)))
 970       (cond
 971        ((and where join-where)
 972         (setq where (list (apply #'sql-and where join-where))))
 973        ((and (null where) (> (length join-where) 1))
 974         (setq where (list (apply #'sql-and join-where)))))
 975
 976       (let* ((rows (apply #'select
 977                           (append (mapcar #'cdr fullsels)
 978                                   (cons :from
 979                                         (list (append (when from (listify from))
 980                                                       (listify tables))))
 981                                   (list :result-types result-types)
 982                                   (when where
 983                                     (list :where where))
 984                                   args)))
 985              (instances-to-add (- (length rows) (length instances)))
 986              (perhaps-extended-instances
 987               (if (plusp instances-to-add)
 988                   (append instances (do ((i 0 (1+ i))
 989                                          (res nil))
 990                                         ((= i instances-to-add) res)
 991                                       (push (make-list (length sclasses) :initial-element nil) res)))
 992                 instances))
 993              (objects (mapcar
 994                        #'(lambda (row instance)
 995                            (build-objects row sclasses immediate-join-classes sels
 996                                           immediate-join-sels database refresh flatp
 997                                           (if (and flatp (atom instance))
 998                                               (list instance)
 999                                             instance)))
1000                        rows perhaps-extended-instances)))
1001         objects))))
1002
1003 (defmethod instance-refreshed ((instance standard-db-object)))
1004
1005 (defvar *default-caching* t
1006   "Controls whether SELECT caches objects by default. The CommonSQL
1007 specification states caching is on by default.")
1008
1009 (defun select (&rest select-all-args)
1010    "Executes a query on DATABASE, which has a default value of
1011 *DEFAULT-DATABASE*, specified by the SQL expressions supplied
1012 using the remaining arguments in SELECT-ALL-ARGS. The SELECT
1013 argument can be used to generate queries in both functional and
1014 object oriented contexts.
1015
1016 In the functional case, the required arguments specify the
1017 columns selected by the query and may be symbolic SQL expressions
1018 or strings representing attribute identifiers. Type modified
1019 identifiers indicate that the values selected from the specified
1020 column are converted to the specified lisp type. The keyword
1021 arguments ALL, DISTINCT, FROM, GROUP-by, HAVING, ORDER-BY,
1022 SET-OPERATION and WHERE are used to specify, using the symbolic
1023 SQL syntax, the corresponding components of the SQL query
1024 generated by the call to SELECT. RESULT-TYPES is a list of
1025 symbols which specifies the lisp type for each field returned by
1026 the query. If RESULT-TYPES is nil all results are returned as
1027 strings whereas the default value of :auto means that the lisp
1028 types are automatically computed for each field. FIELD-NAMES is t
1029 by default which means that the second value returned is a list
1030 of strings representing the columns selected by the query. If
1031 FIELD-NAMES is nil, the list of column names is not returned as a
1032 second value.
1033
1034 In the object oriented case, the required arguments to SELECT are
1035 symbols denoting View Classes which specify the database tables
1036 to query. In this case, SELECT returns a list of View Class
1037 instances whose slots are set from the attribute values of the
1038 records in the specified table. Slot-value is a legal operator
1039 which can be employed as part of the symbolic SQL syntax used in
1040 the WHERE keyword argument to SELECT. REFRESH is nil by default
1041 which means that the View Class instances returned are retrieved
1042 from a cache if an equivalent call to SELECT has previously been
1043 issued. If REFRESH is true, the View Class instances returned are
1044 updated as necessary from the database and the generic function
1045 INSTANCE-REFRESHED is called to perform any necessary operations
1046 on the updated instances.
1047
1048 In both object oriented and functional contexts, FLATP has a
1049 default value of nil which means that the results are returned as
1050 a list of lists. If FLATP is t and only one result is returned
1051 for each record selected in the query, the results are returned
1052 as elements of a list."
1053
1054    (flet ((select-objects (target-args)
1055             (and target-args
1056                  (every #'(lambda (arg)
1057                             (and (symbolp arg)
1058                                  (find-class arg nil)))
1059                         target-args))))
1060      (multiple-value-bind (target-args qualifier-args)
1061          (query-get-selections select-all-args)
1062        (unless (or *default-database* (getf qualifier-args :database))
1063          (signal-no-database-error nil))
1064
1065        (cond
1066          ((select-objects target-args)
1067           (let ((caching (getf qualifier-args :caching *default-caching*))
1068                 (result-types (getf qualifier-args :result-types :auto))
1069                 (refresh (getf qualifier-args :refresh nil))
1070                 (database (or (getf qualifier-args :database) *default-database*))
1071                 (order-by (getf qualifier-args :order-by)))
1072             (remf qualifier-args :caching)
1073             (remf qualifier-args :refresh)
1074             (remf qualifier-args :result-types)
1075
1076             ;; Add explicity table name to order-by if not specified and only
1077             ;; one selected table. This is required so FIND-ALL won't duplicate
1078             ;; the field
1079             (when (and order-by (= 1 (length target-args)))
1080               (let ((table-name  (view-table (find-class (car target-args))))
1081                     (order-by-list (copy-seq (listify order-by))))
1082
1083                 (loop for i from 0 below (length order-by-list)
1084                       do (etypecase (nth i order-by-list)
1085                            (sql-ident-attribute
1086                             (unless (slot-value (nth i order-by-list) 'qualifier)
1087                               (setf (slot-value (nth i order-by-list) 'qualifier) table-name)))
1088                            (cons
1089                             (unless (slot-value (car (nth i order-by-list)) 'qualifier)
1090                               (setf (slot-value (car (nth i order-by-list)) 'qualifier) table-name)))))
1091                 (setf (getf qualifier-args :order-by) order-by-list)))
1092
1093             (cond
1094               ((null caching)
1095                (apply #'find-all target-args
1096                       (append qualifier-args
1097                               (list :result-types result-types :refresh refresh))))
1098               (t
1099                (let ((cached (records-cache-results target-args qualifier-args database)))
1100                  (cond
1101                    ((and cached (not refresh))
1102                     cached)
1103                    ((and cached refresh)
1104                     (let ((results (apply #'find-all (append (list target-args) qualifier-args `(:instances ,cached :result-types :auto :refresh ,refresh)))))
1105                       (setf (records-cache-results target-args qualifier-args database) results)
1106                       results))
1107                    (t
1108                     (let ((results (apply #'find-all target-args (append qualifier-args
1109                                                                          `(:result-types :auto :refresh ,refresh)))))
1110                       (setf (records-cache-results target-args qualifier-args database) results)
1111                       results))))))))
1112          (t
1113           (let* ((expr (apply #'make-query select-all-args))
1114                  (specified-types
1115                   (mapcar #'(lambda (attrib)
1116                               (if (typep attrib 'sql-ident-attribute)
1117                                   (let ((type (slot-value attrib 'type)))
1118                                     (if type
1119                                         type
1120                                         t))
1121                                   t))
1122                           (slot-value expr 'selections))))
1123             (destructuring-bind (&key (flatp nil)
1124                                       (result-types :auto)
1125                                       (field-names t)
1126                                       (database *default-database*)
1127                                       &allow-other-keys)
1128                 qualifier-args
1129               (query expr :flatp flatp
1130                      :result-types
1131                      ;; specifying a type for an attribute overrides result-types
1132                      (if (some #'(lambda (x) (not (eq t x))) specified-types)
1133                          specified-types
1134                          result-types)
1135                      :field-names field-names
1136                      :database database))))))))
1137
1138 (defun compute-records-cache-key (targets qualifiers)
1139   (list targets
1140         (do ((args *select-arguments* (cdr args))
1141              (results nil))
1142             ((null args) results)
1143           (let* ((arg (car args))
1144                  (value (getf qualifiers arg)))
1145             (when value
1146               (push (list arg
1147                           (typecase value
1148                             (cons (cons (sql (car value)) (cdr value)))
1149                             (%sql-expression (sql value))
1150                             (t value)))
1151                     results))))))
1152
1153 (defun records-cache-results (targets qualifiers database)
1154   (when (record-caches database)
1155     (gethash (compute-records-cache-key targets qualifiers) (record-caches database))))
1156
1157 (defun (setf records-cache-results) (results targets qualifiers database)
1158   (unless (record-caches database)
1159     (setf (record-caches database)
1160           (make-hash-table :test 'equal
1161                            #+allegro   :values    #+allegro :weak
1162                            #+clisp     :weak      #+clisp :value
1163                            #+lispworks :weak-kind #+lispworks :value)))
1164   (setf (gethash (compute-records-cache-key targets qualifiers)
1165                  (record-caches database)) results)
1166   results)
1167
1168
1169
1170 ;;; Serialization functions
1171
1172 (defun write-instance-to-stream (obj stream)
1173   "Writes an instance to a stream where it can be later be read.
1174 NOTE: an error will occur if a slot holds a value which can not be written readably."
1175   (let* ((class (class-of obj))
1176          (alist '()))
1177     (dolist (slot (ordered-class-slots (class-of obj)))
1178       (let ((name (slot-definition-name slot)))
1179         (when (and (not (eq 'view-database name))
1180                    (slot-boundp obj name))
1181           (push (cons name (slot-value obj name)) alist))))
1182     (setq alist (reverse alist))
1183     (write (cons (class-name class) alist) :stream stream :readably t))
1184   obj)
1185
1186 (defun read-instance-from-stream (stream)
1187   (let ((raw (read stream nil nil)))
1188     (when raw
1189       (let ((obj (make-instance (car raw))))
1190         (dolist (pair (cdr raw))
1191           (setf (slot-value obj (car pair)) (cdr pair)))
1192         obj))))