src/code/list.lisp

   1 ;;;; functions to implement lists
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5 ;;;;
   6 ;;;; This software is derived from the CMU CL system, which was
   7 ;;;; written at Carnegie Mellon University and released into the
   8 ;;;; public domain. The software is in the public domain and is
   9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  10 ;;;; files for more information.
  11
  12 (in-package "SB!IMPL")
  13
  14 ;;;; KLUDGE: comment from CMU CL, what does it mean?
  15 ;;;;   NSUBLIS, things at the beginning broken.
  16 ;;;; -- WHN 20000127
  17
  18 (declaim (maybe-inline
  19           tree-equal nth %setnth nthcdr last make-list append
  20           nconc member member-if member-if-not tailp adjoin union
  21           nunion intersection nintersection set-difference nset-difference
  22           set-exclusive-or nset-exclusive-or subsetp acons assoc
  23           assoc-if assoc-if-not rassoc rassoc-if rassoc-if-not subst subst-if
  24           subst-if-not nsubst nsubst-if nsubst-if-not sublis nsublis))
  25
  26 ;;; These functions perform basic list operations.
  27 (defun car (list) #!+sb-doc "Return the 1st object in a list." (car list))
  28 (defun cdr (list)
  29   #!+sb-doc "Return all but the first object in a list."
  30   (cdr list))
  31 (defun cadr (list) #!+sb-doc "Return the 2nd object in a list." (cadr list))
  32 (defun cdar (list) #!+sb-doc "Return the cdr of the 1st sublist." (cdar list))
  33 (defun caar (list) #!+sb-doc "Return the car of the 1st sublist." (caar list))
  34 (defun cddr (list)
  35   #!+sb-doc "Return all but the 1st two objects of a list."
  36   (cddr list))
  37 (defun caddr (list)
  38   #!+sb-doc "Return the 1st object in the cddr of a list."
  39   (caddr list))
  40 (defun caadr (list)
  41   #!+sb-doc "Return the 1st object in the cadr of a list."
  42   (caadr list))
  43 (defun caaar (list)
  44   #!+sb-doc "Return the 1st object in the caar of a list."
  45   (caaar list))
  46 (defun cdaar (list)
  47   #!+sb-doc "Return the cdr of the caar of a list."
  48   (cdaar list))
  49 (defun cddar (list)
  50   #!+sb-doc "Return the cdr of the cdar of a list."
  51   (cddar list))
  52 (defun cdddr (list)
  53   #!+sb-doc "Return the cdr of the cddr of a list."
  54   (cdddr list))
  55 (defun cadar (list)
  56   #!+sb-doc "Return the car of the cdar of a list."
  57   (cadar list))
  58 (defun cdadr (list)
  59   #!+sb-doc "Return the cdr of the cadr of a list."
  60   (cdadr list))
  61 (defun caaaar (list)
  62   #!+sb-doc "Return the car of the caaar of a list."
  63   (caaaar list))
  64 (defun caaadr (list)
  65   #!+sb-doc "Return the car of the caadr of a list."
  66   (caaadr list))
  67 (defun caaddr (list)
  68   #!+sb-doc "Return the car of the caddr of a list."
  69   (caaddr list))
  70 (defun cadddr (list)
  71   #!+sb-doc "Return the car of the cdddr of a list."
  72   (cadddr list))
  73 (defun cddddr (list)
  74   #!+sb-doc "Return the cdr of the cdddr of a list."
  75   (cddddr list))
  76 (defun cdaaar (list)
  77   #!+sb-doc "Return the cdr of the caaar of a list."
  78   (cdaaar list))
  79 (defun cddaar (list)
  80   #!+sb-doc "Return the cdr of the cdaar of a list."
  81   (cddaar list))
  82 (defun cdddar (list)
  83   #!+sb-doc "Return the cdr of the cddar of a list."
  84   (cdddar list))
  85 (defun caadar (list)
  86   #!+sb-doc "Return the car of the cadar of a list."
  87   (caadar list))
  88 (defun cadaar (list)
  89   #!+sb-doc "Return the car of the cdaar of a list."
  90   (cadaar list))
  91 (defun cadadr (list)
  92   #!+sb-doc "Return the car of the cdadr of a list."
  93   (cadadr list))
  94 (defun caddar (list)
  95   #!+sb-doc "Return the car of the cddar of a list."
  96   (caddar list))
  97 (defun cdaadr (list)
  98   #!+sb-doc "Return the cdr of the caadr of a list."
  99   (cdaadr list))
 100 (defun cdadar (list)
 101   #!+sb-doc "Return the cdr of the cadar of a list."
 102   (cdadar list))
 103 (defun cdaddr (list)
 104   #!+sb-doc "Return the cdr of the caddr of a list."
 105   (cdaddr list))
 106 (defun cddadr (list)
 107   #!+sb-doc "Return the cdr of the cdadr of a list."
 108   (cddadr list))
 109 (defun cons (se1 se2)
 110   #!+sb-doc "Return a list with SE1 as the CAR and SE2 as the CDR."
 111   (cons se1 se2))
 112 \f
 113 (declaim (maybe-inline tree-equal-test tree-equal-test-not))
 114
 115 (defun tree-equal-test-not (x y test-not)
 116   (declare (type function test-not))
 117   (cond ((consp x)
 118          (and (consp y)
 119               (tree-equal-test-not (car x) (car y) test-not)
 120               (tree-equal-test-not (cdr x) (cdr y) test-not)))
 121         ((consp y) nil)
 122         ((not (funcall test-not x y)) t)
 123         (t ())))
 124
 125 (defun tree-equal-test (x y test)
 126   (declare (type function test))
 127   (cond ((consp x)
 128          (and (consp y)
 129               (tree-equal-test (car x) (car y) test)
 130               (tree-equal-test (cdr x) (cdr y) test)))
 131         ((consp y) nil)
 132         ((funcall test x y) t)
 133         (t ())))
 134
 135 (defun tree-equal (x y &key (test #'eql testp) (test-not nil notp))
 136   #!+sb-doc
 137   "Return T if X and Y are isomorphic trees with identical leaves."
 138   (when (and testp notp)
 139     (error ":TEST and :TEST-NOT were both supplied."))
 140   (if test-not
 141       (tree-equal-test-not x y (%coerce-callable-to-fun test-not))
 142       (tree-equal-test x y (%coerce-callable-to-fun test))))
 143
 144 (defun endp (object)
 145   #!+sb-doc
 146   "This is the recommended way to test for the end of a proper list. It
 147    returns true if OBJECT is NIL, false if OBJECT is a CONS, and an error
 148    for any other type of OBJECT."
 149   (endp object))
 150
 151 (defun list-length (list)
 152   #!+sb-doc
 153   "Return the length of the given List, or Nil if the List is circular."
 154   (do ((n 0 (+ n 2))
 155        (y list (cddr y))
 156        (z list (cdr z)))
 157       (())
 158     (declare (type fixnum n)
 159              (type list y z))
 160     (when (endp y) (return n))
 161     (when (endp (cdr y)) (return (+ n 1)))
 162     (when (and (eq y z) (> n 0)) (return nil))))
 163
 164 (defun nth (n list)
 165   #!+sb-doc
 166   "Return the nth object in a list where the car is the zero-th element."
 167   (car (nthcdr n list)))
 168
 169 (defun first (list)
 170   #!+sb-doc
 171   "Return the 1st object in a list or NIL if the list is empty."
 172   (car list))
 173 (defun second (list)
 174   "Return the 2nd object in a list or NIL if there is no 2nd object."
 175   (cadr list))
 176 (defun third (list)
 177   #!+sb-doc
 178   "Return the 3rd object in a list or NIL if there is no 3rd object."
 179   (caddr list))
 180 (defun fourth (list)
 181   #!+sb-doc
 182   "Return the 4th object in a list or NIL if there is no 4th object."
 183   (cadddr list))
 184 (defun fifth (list)
 185   #!+sb-doc
 186   "Return the 5th object in a list or NIL if there is no 5th object."
 187   (car (cddddr list)))
 188 (defun sixth (list)
 189   #!+sb-doc
 190   "Return the 6th object in a list or NIL if there is no 6th object."
 191   (cadr (cddddr list)))
 192 (defun seventh (list)
 193   #!+sb-doc
 194   "Return the 7th object in a list or NIL if there is no 7th object."
 195   (caddr (cddddr list)))
 196 (defun eighth (list)
 197   #!+sb-doc
 198   "Return the 8th object in a list or NIL if there is no 8th object."
 199   (cadddr (cddddr list)))
 200 (defun ninth (list)
 201   #!+sb-doc
 202   "Return the 9th object in a list or NIL if there is no 9th object."
 203   (car (cddddr (cddddr list))))
 204 (defun tenth (list)
 205   #!+sb-doc
 206   "Return the 10th object in a list or NIL if there is no 10th object."
 207   (cadr (cddddr (cddddr list))))
 208 (defun rest (list)
 209   #!+sb-doc
 210   "Means the same as the cdr of a list."
 211   (cdr list))
 212
 213 (defun nthcdr (n list)
 214   (declare (type index n))
 215   #!+sb-doc
 216   "Performs the cdr function n times on a list."
 217   (do ((i n (1- i))
 218        (result list (cdr result)))
 219       ((not (plusp i)) result)
 220       (declare (type index i))))
 221
 222 (defun last (list &optional (n 1))
 223   #!+sb-doc
 224   "Return the last N conses (not the last element!) of a list."
 225   (declare (type index n))
 226   (do ((checked-list list (cdr checked-list))
 227        (returned-list list)
 228        (index 0 (1+ index)))
 229       ((atom checked-list) returned-list)
 230     (declare (type index index))
 231     (if (>= index n)
 232         (pop returned-list))))
 233
 234 (defun list (&rest args)
 235   #!+sb-doc
 236   "Return constructs and returns a list of its arguments."
 237   args)
 238
 239 ;;; LIST* is done the same as LIST, except that the last cons is made
 240 ;;; a dotted pair.
 241
 242 (defun list* (arg &rest others)
 243   #!+sb-doc
 244   "Return a list of the arguments with last cons a dotted pair"
 245   (cond ((atom others) arg)
 246         ((atom (cdr others)) (cons arg (car others)))
 247         (t (do ((x others (cdr x)))
 248                ((null (cddr x)) (rplacd x (cadr x))))
 249            (cons arg others))))
 250
 251 (defun make-list (size &key initial-element)
 252   #!+sb-doc
 253   "Constructs a list with size elements each set to value"
 254   (declare (type index size))
 255   (do ((count size (1- count))
 256        (result '() (cons initial-element result)))
 257       ((zerop count) result)
 258     (declare (type index count))))
 259 \f
 260 (defun append (&rest lists)
 261   #!+sb-doc
 262   "Construct a new list by concatenating the list arguments"
 263   (labels ((fail (object)
 264              (error 'type-error
 265                     :datum object
 266                     :expected-type 'list))
 267            (append-into (last-cons current rest)
 268              "Set (CDR LAST-CONS) to (APPLY #'APPEND CURRENT REST)."
 269              (declare (cons last-cons rest))
 270              (cond ((consp current)
 271                     (append-into (setf (cdr last-cons) (list (car current)))
 272                                 (cdr current)
 273                                 rest))
 274                    ((not (null current)) (fail current))
 275                    ((null (cdr rest)) (setf (cdr last-cons) (car rest)))
 276                    (t (append-into last-cons (car rest) (cdr rest)))))
 277            (append1 (lists)
 278              (let ((current (car lists))
 279                    (rest (cdr lists)))
 280                (cond ((null rest) current)
 281                      ((consp current)
 282                       (let ((result (truly-the cons (list (car current)))))
 283                         (append-into result
 284                                     (cdr current)
 285                                     rest)
 286                         result))
 287                      ((null current) (append1 rest))
 288                      (t (fail current))))))
 289     (append1 lists)))
 290 \f
 291 ;;;; list copying functions
 292
 293 (defun copy-list (list)
 294   #!+sb-doc
 295   "Return a new list which is EQUAL to LIST."
 296   ;; The list is copied correctly even if the list is not terminated
 297   ;; by NIL. The new list is built by CDR'ing SPLICE which is always
 298   ;; at the tail of the new list.
 299   (if (atom list)
 300       list
 301       (let ((result (list (car list))))
 302         (do ((x (cdr list) (cdr x))
 303              (splice result
 304                      (cdr (rplacd splice (cons (car x) '())))))
 305             ((atom x)
 306              (unless (null x)
 307                (rplacd splice x))))
 308         result)))
 309
 310 (defun copy-alist (alist)
 311   #!+sb-doc
 312   "Return a new association list which is EQUAL to ALIST."
 313   (if (endp alist)
 314       alist
 315       (let ((result
 316              (cons (if (atom (car alist))
 317                        (car alist)
 318                        (cons (caar alist) (cdar alist)))
 319                    nil)))
 320         (do ((x (cdr alist) (cdr x))
 321              (splice result
 322                      (cdr (rplacd splice
 323                                   (cons
 324                                    (if (atom (car x))
 325                                        (car x)
 326                                        (cons (caar x) (cdar x)))
 327                                    nil)))))
 328             ((endp x)))
 329         result)))
 330
 331 (defun copy-tree (object)
 332   #!+sb-doc
 333   "Recursively copy trees of conses."
 334   (if (consp object)
 335       (cons (copy-tree (car object)) (copy-tree (cdr object)))
 336       object))
 337 \f
 338 ;;;; more commonly-used list functions
 339
 340 (defun revappend (x y)
 341   #!+sb-doc
 342   "Return (append (reverse x) y)."
 343   (do ((top x (cdr top))
 344        (result y (cons (car top) result)))
 345       ((endp top) result)))
 346
 347 ;;; NCONC finds the first non-null list, so it can make splice point
 348 ;;; to a cons. After finding the first cons element, it holds it in a
 349 ;;; result variable while running down successive elements tacking
 350 ;;; them together. While tacking lists together, if we encounter a
 351 ;;; null list, we set the previous list's last cdr to nil just in case
 352 ;;; it wasn't already nil, and it could have been dotted while the
 353 ;;; null list was the last argument to NCONC. The manipulation of
 354 ;;; splice (that is starting it out on a first cons, setting LAST of
 355 ;;; splice, and setting splice to ele) inherently handles (nconc x x),
 356 ;;; and it avoids running down the last argument to NCONC which allows
 357 ;;; the last argument to be circular.
 358 (defun nconc (&rest lists)
 359   #!+sb-doc
 360   "Concatenates the lists given as arguments (by changing them)"
 361   (flet ((fail (object)
 362            (error 'type-error
 363                   :datum object
 364                   :expected-type 'list)))
 365     (do ((top lists (cdr top)))
 366         ((null top) nil)
 367       (let ((top-of-top (car top)))
 368         (typecase top-of-top
 369           (cons
 370            (let* ((result top-of-top)
 371                   (splice result))
 372              (do ((elements (cdr top) (cdr elements)))
 373                  ((endp elements))
 374                (let ((ele (car elements)))
 375                  (typecase ele
 376                    (cons (rplacd (last splice) ele)
 377                          (setf splice ele))
 378                    (null (rplacd (last splice) nil))
 379                    (atom (if (cdr elements)
 380                              (fail ele)
 381                              (rplacd (last splice) ele)))
 382                    (t (fail ele)))))
 383              (return result)))
 384           (null)
 385           (atom
 386            (if (cdr top)
 387                (fail top-of-top)
 388                (return top-of-top)))
 389           (t (fail top-of-top)))))))
 390
 391 (defun nreconc (x y)
 392   #!+sb-doc
 393   "Return (NCONC (NREVERSE X) Y)."
 394   (do ((1st (cdr x) (if (endp 1st) 1st (cdr 1st)))
 395        (2nd x 1st)              ;2nd follows first down the list.
 396        (3rd y 2nd))             ;3rd follows 2nd down the list.
 397       ((atom 2nd) 3rd)
 398     (rplacd 2nd 3rd)))
 399 \f
 400 (flet (;; Return the number of conses at the head of the
 401        ;; possibly-improper list LIST. (Or if LIST is circular, you
 402        ;; lose.)
 403        (count-conses (list)
 404          (do ((in-list list (cdr in-list))
 405               (result 0 (1+ result)))
 406              ((atom in-list)
 407               result)
 408            (declare (type index result)))))
 409   (declare (ftype (function (t) index) count-conses))
 410   (defun butlast (list &optional (n 1))
 411     (let ((n-conses-in-list (count-conses list)))
 412       (cond ((zerop n)
 413              ;; (We can't use SUBSEQ in this case because LIST isn't
 414              ;; necessarily a proper list, but SUBSEQ expects a
 415              ;; proper sequence. COPY-LIST isn't so fussy.)
 416              (copy-list list))
 417             ((>= n n-conses-in-list)
 418              nil)
 419             (t
 420              ;; (LIST isn't necessarily a proper list in this case
 421              ;; either, and technically SUBSEQ wants a proper
 422              ;; sequence, but no reasonable implementation of SUBSEQ
 423              ;; will actually walk down to the end of the list to
 424              ;; check, and since we're calling our own implementation
 425              ;; we know it's reasonable, so it's OK.)
 426              (subseq list 0 (- n-conses-in-list n))))))
 427   (defun nbutlast (list &optional (n 1))
 428     (if (zerop n)
 429         list
 430         (let ((n-conses-in-list (count-conses list)))
 431           (unless (<= n-conses-in-list n)
 432             (setf (cdr (nthcdr (- n-conses-in-list n 1) list))
 433                   nil)
 434             list)))))
 435
 436 (defun ldiff (list object)
 437   "Return a new list, whose elements are those of LIST that appear before
 438    OBJECT. If OBJECT is not a tail of LIST, a copy of LIST is returned.
 439    LIST must be a proper list or a dotted list."
 440   (do* ((list list (cdr list))
 441         (result (list ()))
 442         (splice result))
 443        ((atom list)
 444         (if (eql list object)
 445             (cdr result)
 446             (progn (rplacd splice list) (cdr result))))
 447     (if (eql list object)
 448         (return (cdr result))
 449         (setq splice (cdr (rplacd splice (list (car list))))))))
 450 \f
 451 ;;;; functions to alter list structure
 452
 453 (defun rplaca (x y)
 454   #!+sb-doc
 455   "Change the CAR of X to Y and return the new X."
 456   (rplaca x y))
 457
 458 (defun rplacd (x y)
 459   #!+sb-doc
 460   "Change the CDR of X to Y and return the new X."
 461   (rplacd x y))
 462
 463 ;;; The following are for use by SETF.
 464
 465 (defun %rplaca (x val) (rplaca x val) val)
 466
 467 (defun %rplacd (x val) (rplacd x val) val)
 468
 469 ;;; Set the Nth element of LIST to NEWVAL.
 470 (defun %setnth (n list newval)
 471   (declare (type index n))
 472   (do ((count n (1- count))
 473        (list list (cdr list)))
 474       ((endp list)
 475        (error "~S is too large an index for SETF of NTH." n))
 476     (declare (type fixnum count))
 477     (when (<= count 0)
 478       (rplaca list newval)
 479       (return newval))))
 480 \f
 481 ;;;; :KEY arg optimization to save funcall of IDENTITY
 482
 483 ;;; APPLY-KEY saves us a function call sometimes.
 484 ;;;    This isn't wrapped in an (EVAL-WHEN (COMPILE EVAL) ..)
 485 ;;;    because it's used in seq.lisp and sort.lisp.
 486 (defmacro apply-key (key element)
 487   `(if ,key
 488        (funcall ,key ,element)
 489        ,element))
 490 \f
 491 ;;;; macros for (&KEY (KEY #'IDENTITY) (TEST #'EQL TESTP) (TEST-NOT NIL NOTP))
 492
 493 ;;; Use these with the following &KEY args:
 494 (defmacro with-set-keys (funcall)
 495   `(if notp
 496        ,(append funcall '(:key key :test-not test-not))
 497        ,(append funcall '(:key key :test test))))
 498
 499 (defmacro satisfies-the-test (item elt)
 500   (let ((key-tmp (gensym)))
 501     `(let ((,key-tmp (apply-key key ,elt)))
 502       (cond (testp (funcall test ,item ,key-tmp))
 503             (notp (not (funcall test-not ,item ,key-tmp)))
 504             (t (funcall test ,item ,key-tmp))))))
 505 \f
 506 ;;;; substitution of expressions
 507
 508 (defun subst (new old tree &key key (test #'eql testp) (test-not #'eql notp))
 509   #!+sb-doc
 510   "Substitutes new for subtrees matching old."
 511   (when (and testp notp)
 512     (error ":TEST and :TEST-NOT were both supplied."))
 513   (let ((key (and key (%coerce-callable-to-fun key)))
 514         (test (if testp (%coerce-callable-to-fun test) test))
 515         (test-not (if notp (%coerce-callable-to-fun test-not) test-not)))
 516     (declare (type function test test-not))
 517     (labels ((s (subtree)
 518                (cond ((satisfies-the-test old subtree) new)
 519                      ((atom subtree) subtree)
 520                      (t (let ((car (s (car subtree)))
 521                               (cdr (s (cdr subtree))))
 522                           (if (and (eq car (car subtree))
 523                                    (eq cdr (cdr subtree)))
 524                               subtree
 525                               (cons car cdr)))))))
 526       (s tree))))
 527
 528 (defun subst-if (new test tree &key key)
 529   #!+sb-doc
 530   "Substitutes new for subtrees for which test is true."
 531   (let ((test (%coerce-callable-to-fun test))
 532         (key (and key (%coerce-callable-to-fun key))))
 533     (labels ((s (subtree)
 534                (cond ((funcall test (apply-key key subtree)) new)
 535                      ((atom subtree) subtree)
 536                      (t (let ((car (s (car subtree)))
 537                               (cdr (s (cdr subtree))))
 538                           (if (and (eq car (car subtree))
 539                                    (eq cdr (cdr subtree)))
 540                               subtree
 541                               (cons car cdr)))))))
 542       (s tree))))
 543
 544 (defun subst-if-not (new test tree &key key)
 545   #!+sb-doc
 546   "Substitutes new for subtrees for which test is false."
 547   (let ((test (%coerce-callable-to-fun test))
 548         (key (and key (%coerce-callable-to-fun key))))
 549     (labels ((s (subtree)
 550                (cond ((not (funcall test (apply-key key subtree))) new)
 551                      ((atom subtree) subtree)
 552                      (t (let ((car (s (car subtree)))
 553                               (cdr (s (cdr subtree))))
 554                           (if (and (eq car (car subtree))
 555                                    (eq cdr (cdr subtree)))
 556                               subtree
 557                               (cons car cdr)))))))
 558       (s tree))))
 559
 560 (defun nsubst (new old tree &key key (test #'eql testp) (test-not #'eql notp))
 561   #!+sb-doc
 562   "Substitute NEW for subtrees matching OLD."
 563   (when (and testp notp)
 564     (error ":TEST and :TEST-NOT were both supplied."))
 565   (let ((key (and key (%coerce-callable-to-fun key)))
 566         (test (if testp (%coerce-callable-to-fun test) test))
 567         (test-not (if notp (%coerce-callable-to-fun test-not) test-not)))
 568     (declare (type function test test-not))
 569     (labels ((s (subtree)
 570                (cond ((satisfies-the-test old subtree) new)
 571                      ((atom subtree) subtree)
 572                      (t (do* ((last nil subtree)
 573                               (subtree subtree (Cdr subtree)))
 574                              ((atom subtree)
 575                               (if (satisfies-the-test old subtree)
 576                                   (setf (cdr last) new)))
 577                           (if (satisfies-the-test old subtree)
 578                               (return (setf (cdr last) new))
 579                               (setf (car subtree) (s (car subtree)))))
 580                         subtree))))
 581       (s tree))))
 582
 583 (defun nsubst-if (new test tree &key key)
 584   #!+sb-doc
 585   "Substitute NEW for subtrees of TREE for which TEST is true."
 586   (let ((test (%coerce-callable-to-fun test))
 587         (key (and key (%coerce-callable-to-fun key))))
 588     (labels ((s (subtree)
 589                (cond ((funcall test (apply-key key subtree)) new)
 590                      ((atom subtree) subtree)
 591                      (t (do* ((last nil subtree)
 592                               (subtree subtree (Cdr subtree)))
 593                              ((atom subtree)
 594                               (if (funcall test (apply-key key subtree))
 595                                   (setf (cdr last) new)))
 596                           (if (funcall test (apply-key key subtree))
 597                               (return (setf (cdr last) new))
 598                               (setf (car subtree) (s (car subtree)))))
 599                         subtree))))
 600       (s tree))))
 601
 602 (defun nsubst-if-not (new test tree &key key)
 603   #!+sb-doc
 604   "Substitute NEW for subtrees of TREE for which TEST is false."
 605   (let ((test (%coerce-callable-to-fun test))
 606         (key (and key (%coerce-callable-to-fun key))))
 607     (labels ((s (subtree)
 608                (cond ((not (funcall test (apply-key key subtree))) new)
 609                      ((atom subtree) subtree)
 610                      (t (do* ((last nil subtree)
 611                               (subtree subtree (Cdr subtree)))
 612                              ((atom subtree)
 613                               (if (not (funcall test (apply-key key subtree)))
 614                                   (setf (cdr last) new)))
 615                           (if (not (funcall test (apply-key key subtree)))
 616                               (return (setf (cdr last) new))
 617                               (setf (car subtree) (s (car subtree)))))
 618                         subtree))))
 619       (s tree))))
 620 \f
 621 (defun sublis (alist tree &key key (test #'eql testp) (test-not #'eql notp))
 622   #!+sb-doc
 623   "Substitute from ALIST into TREE nondestructively."
 624   (when (and testp notp)
 625     (error ":TEST and :TEST-NOT were both supplied."))
 626   (let ((key (and key (%coerce-callable-to-fun key)))
 627         (test (if testp (%coerce-callable-to-fun test) test))
 628         (test-not (if notp (%coerce-callable-to-fun test-not) test-not)))
 629     (declare (type function test test-not))
 630     (declare (inline assoc))
 631     (labels ((s (subtree)
 632                (let* ((key-val (apply-key key subtree))
 633                       (assoc (if notp
 634                                  (assoc key-val alist :test-not test-not)
 635                                  (assoc key-val alist :test test))))
 636                  (cond (assoc (cdr assoc))
 637                        ((atom subtree) subtree)
 638                        (t (let ((car (s (car subtree)))
 639                                 (cdr (s (cdr subtree))))
 640                             (if (and (eq car (car subtreE))
 641                                      (eq cdr (cdr subtree)))
 642                                 subtree
 643                                 (cons car cdr))))))))
 644       (s tree))))
 645
 646 ;;; This is in run-time env (i.e. not wrapped in EVAL-WHEN (COMPILE EVAL))
 647 ;;; because it can be referenced in inline expansions.
 648 (defmacro nsublis-macro ()
 649   (let ((key-tmp (gensym)))
 650     `(let ((,key-tmp (apply-key key subtree)))
 651       (if notp
 652           (assoc ,key-tmp alist :test-not test-not)
 653           (assoc ,key-tmp alist :test test)))))
 654
 655 (defun nsublis (alist tree &key key (test #'eql testp) (test-not #'eql notp))
 656   #!+sb-doc
 657   "Substitute from ALIST into TRUE destructively."
 658   (when (and testp notp)
 659     (error ":TEST and :TEST-NOT were both supplied."))
 660   (let ((key (and key (%coerce-callable-to-fun key)))
 661         (test (if testp (%coerce-callable-to-fun test) test))
 662         (test-not (if notp (%coerce-callable-to-fun test-not) test-not)))
 663     (declare (inline assoc))
 664     (let (temp)
 665       (labels ((s (subtree)
 666                  (cond ((Setq temp (nsublis-macro))
 667                         (cdr temp))
 668                        ((atom subtree) subtree)
 669                        (t (do* ((last nil subtree)
 670                                 (subtree subtree (Cdr subtree)))
 671                                ((atom subtree)
 672                                 (if (setq temp (nsublis-macro))
 673                                     (setf (cdr last) (cdr temp))))
 674                             (if (setq temp (nsublis-macro))
 675                                 (return (setf (Cdr last) (Cdr temp)))
 676                                 (setf (car subtree) (s (car subtree)))))
 677                           subtree))))
 678         (s tree)))))
 679 \f
 680 ;;;; functions for using lists as sets
 681
 682 (defun member (item list &key key (test #'eql testp) (test-not #'eql notp))
 683   #!+sb-doc
 684   "Return the tail of LIST beginning with first element satisfying EQLity,
 685    :TEST, or :TEST-NOT with the given ITEM."
 686   (when (and testp notp)
 687     (error ":TEST and :TEST-NOT were both supplied."))
 688   (let ((key (and key (%coerce-callable-to-fun key)))
 689         (test (if testp (%coerce-callable-to-fun test) test))
 690         (test-not (if notp (%coerce-callable-to-fun test-not) test-not)))
 691     (declare (type function test test-not))
 692     (do ((list list (cdr list)))
 693         ((null list) nil)
 694       (let ((car (car list)))
 695         (if (satisfies-the-test item car)
 696             (return list))))))
 697
 698 (defun member-if (test list &key key)
 699   #!+sb-doc
 700   "Return tail of LIST beginning with first element satisfying TEST."
 701   (let ((test (%coerce-callable-to-fun test))
 702         (key (and key (%coerce-callable-to-fun key))))
 703     (do ((list list (cdr list)))
 704         ((endp list) nil)
 705       (if (funcall test (apply-key key (car list)))
 706           (return list)))))
 707
 708 (defun member-if-not (test list &key key)
 709   #!+sb-doc
 710   "Return tail of LIST beginning with first element not satisfying TEST."
 711   (let ((test (%coerce-callable-to-fun test))
 712         (key (and key (%coerce-callable-to-fun key))))
 713     (do ((list list (cdr list)))
 714         ((endp list) ())
 715       (if (not (funcall test (apply-key key (car list))))
 716           (return list)))))
 717
 718 (defun tailp (object list)
 719   #!+sb-doc
 720   "Return true if OBJECT is the same as some tail of LIST, otherwise
 721    returns false. LIST must be a proper list or a dotted list."
 722   (do ((list list (cdr list)))
 723       ((atom list) (eql list object))
 724     (if (eql object list)
 725         (return t))))
 726
 727 (defun adjoin (item list &key key (test #'eql testp) (test-not nil notp))
 728   #!+sb-doc
 729   "Add ITEM to LIST unless it is already a member"
 730   (when (and testp notp)
 731     (error ":TEST and :TEST-NOT were both supplied."))
 732   (let ((key (and key (%coerce-callable-to-fun key))))
 733     (declare (inline member))
 734     (if (let ((key-val (apply-key key item)))
 735           (if notp
 736               (member key-val list :test-not test-not :key key)
 737               (member key-val list :test test :key key)))
 738         list
 739         (cons item list))))
 740
 741 (defun union (list1 list2 &key key (test #'eql testp) (test-not nil notp))
 742   #!+sb-doc
 743   "Return the union of LIST1 and LIST2."
 744   (declare (inline member))
 745   (when (and testp notp)
 746     (error ":TEST and :TEST-NOT were both supplied."))
 747   ;; We assumes LIST2 is the result, adding to it from LIST1 as
 748   ;; necessary. LIST2 must initialize the result value, so the call to
 749   ;; MEMBER will apply the test to the elements from LIST1 and LIST2
 750   ;; in the correct order.
 751   (let ((key (and key (%coerce-callable-to-fun key))))
 752     (let ((res list2))
 753       (dolist (elt list1)
 754         (unless (with-set-keys (member (apply-key key elt) list2))
 755           (push elt res)))
 756       res)))
 757
 758 ;;; Destination and source are SETF-able and many-evaluable. Set the
 759 ;;; SOURCE to the CDR, and "cons" the 1st elt of source to DESTINATION.
 760 ;;;
 761 ;;; FIXME: needs a more mnemonic name
 762 (defmacro steve-splice (source destination)
 763   `(let ((temp ,source))
 764      (setf ,source (cdr ,source)
 765            (cdr temp) ,destination
 766            ,destination temp)))
 767
 768 (defun nunion (list1 list2 &key key (test #'eql testp) (test-not nil notp))
 769   #!+sb-doc
 770   "Destructively return the union of LIST1 and LIST2."
 771   (declare (inline member))
 772   (when (and testp notp)
 773     (error ":TEST and :TEST-NOT were both supplied."))
 774   (let ((key (and key (%coerce-callable-to-fun key))))
 775     (let ((res list2)
 776           (list1 list1))
 777       (do ()
 778           ((endp list1))
 779         (if (not (with-set-keys (member (apply-key key (car list1)) list2)))
 780             (steve-splice list1 res)
 781             (setf list1 (cdr list1))))
 782       res)))
 783
 784 (defun intersection (list1 list2
 785                      &key key (test #'eql testp) (test-not nil notp))
 786   #!+sb-doc
 787   "Return the intersection of LIST1 and LIST2."
 788   (declare (inline member))
 789   (when (and testp notp)
 790     (error ":TEST and :TEST-NOT were both supplied."))
 791   (let ((key (and key (%coerce-callable-to-fun key))))
 792     (let ((res nil))
 793       (dolist (elt list1)
 794         (if (with-set-keys (member (apply-key key elt) list2))
 795             (push elt res)))
 796       res)))
 797
 798 (defun nintersection (list1 list2
 799                       &key key (test #'eql testp) (test-not nil notp))
 800   #!+sb-doc
 801   "Destructively return the intersection of LIST1 and LIST2."
 802   (declare (inline member))
 803   (when (and testp notp)
 804     (error ":TEST and :TEST-NOT were both supplied."))
 805   (let ((key (and key (%coerce-callable-to-fun key))))
 806     (let ((res nil)
 807           (list1 list1))
 808       (do () ((endp list1))
 809         (if (with-set-keys (member (apply-key key (car list1)) list2))
 810             (steve-splice list1 res)
 811             (setq list1 (Cdr list1))))
 812       res)))
 813
 814 (defun set-difference (list1 list2
 815                        &key key (test #'eql testp) (test-not nil notp))
 816   #!+sb-doc
 817   "Return the elements of LIST1 which are not in LIST2."
 818   (declare (inline member))
 819   (when (and testp notp)
 820     (error ":TEST and :TEST-NOT were both supplied."))
 821   (let ((key (and key (%coerce-callable-to-fun key))))
 822     (if (null list2)
 823         list1
 824         (let ((res nil))
 825           (dolist (elt list1)
 826             (if (not (with-set-keys (member (apply-key key elt) list2)))
 827                 (push elt res)))
 828           res))))
 829
 830 (defun nset-difference (list1 list2
 831                         &key key (test #'eql testp) (test-not nil notp))
 832   #!+sb-doc
 833   "Destructively return the elements of LIST1 which are not in LIST2."
 834   (declare (inline member))
 835   (when (and testp notp)
 836     (error ":TEST and :TEST-NOT were both supplied."))
 837   (let ((key (and key (%coerce-callable-to-fun key))))
 838     (let ((res nil)
 839           (list1 list1))
 840       (do () ((endp list1))
 841         (if (not (with-set-keys (member (apply-key key (car list1)) list2)))
 842             (steve-splice list1 res)
 843             (setq list1 (cdr list1))))
 844       res)))
 845
 846 (defun set-exclusive-or (list1 list2
 847                          &key key (test #'eql testp) (test-not #'eql notp))
 848   #!+sb-doc
 849   "Return new list of elements appearing exactly once in LIST1 and LIST2."
 850   (declare (inline member))
 851   (when (and testp notp)
 852     (error ":TEST and :TEST-NOT were both supplied."))
 853   (let ((result nil)
 854         (key (and key (%coerce-callable-to-fun key)))
 855         (test (if testp (%coerce-callable-to-fun test) test))
 856         (test-not (if notp (%coerce-callable-to-fun test-not) test-not)))
 857     (declare (type function test test-not))
 858     (dolist (elt list1)
 859       (unless (with-set-keys (member (apply-key key elt) list2))
 860         (setq result (cons elt result))))
 861     (let ((test (if testp
 862                     (lambda (x y) (funcall test y x))
 863                     test))
 864           (test-not (if notp
 865                         (lambda (x y) (funcall test-not y x))
 866                         test-not)))
 867       (dolist (elt list2)
 868         (unless (with-set-keys (member (apply-key key elt) list1))
 869           (setq result (cons elt result)))))
 870     result))
 871
 872 (defun nset-exclusive-or (list1 list2
 873                           &key key (test #'eql testp) (test-not #'eql notp))
 874   #!+sb-doc
 875   "Destructively return a list with elements which appear but once in LIST1
 876    and LIST2."
 877   (when (and testp notp)
 878     (error ":TEST and :TEST-NOT were both supplied."))
 879   (let ((key (and key (%coerce-callable-to-fun key)))
 880         (test (if testp (%coerce-callable-to-fun test) test))
 881         (test-not (if notp (%coerce-callable-to-fun test-not) test-not)))
 882     (declare (type function test test-not))
 883     ;; The outer loop examines LIST1 while the inner loop examines
 884     ;; LIST2. If an element is found in LIST2 "equal" to the element
 885     ;; in LIST1, both are spliced out. When the end of LIST1 is
 886     ;; reached, what is left of LIST2 is tacked onto what is left of
 887     ;; LIST1. The splicing operation ensures that the correct
 888     ;; operation is performed depending on whether splice is at the
 889     ;; top of the list or not
 890     (do ((list1 list1)
 891          (list2 list2)
 892          (x list1 (cdr x))
 893          (splicex ()))
 894         ((endp x)
 895          (if (null splicex)
 896              (setq list1 list2)
 897              (rplacd splicex list2))
 898          list1)
 899       (do ((y list2 (cdr y))
 900            (splicey ()))
 901           ((endp y) (setq splicex x))
 902         (cond ((let ((key-val-x (apply-key key (car x)))
 903                      (key-val-y (apply-key key (Car y))))
 904                  (if notp
 905                      (not (funcall test-not key-val-x key-val-y))
 906                      (funcall test key-val-x key-val-y)))
 907                (if (null splicex)
 908                    (setq list1 (cdr x))
 909                    (rplacd splicex (cdr x)))
 910                (if (null splicey)
 911                    (setq list2 (cdr y))
 912                    (rplacd splicey (cdr y)))
 913                (return ())) ; assume lists are really sets
 914               (t (setq splicey y)))))))
 915
 916 (defun subsetp (list1 list2 &key key (test #'eql testp) (test-not nil notp))
 917   #!+sb-doc
 918   "Return T if every element in LIST1 is also in LIST2."
 919   (declare (inline member))
 920   (when (and testp notp)
 921     (error ":TEST and :TEST-NOT were both supplied."))
 922   (let ((key (and key (%coerce-callable-to-fun key))))
 923     (dolist (elt list1)
 924       (unless (with-set-keys (member (apply-key key elt) list2))
 925         (return-from subsetp nil)))
 926     t))
 927 \f
 928 ;;;; functions that operate on association lists
 929
 930 (defun acons (key datum alist)
 931   #!+sb-doc
 932   "Construct a new alist by adding the pair (KEY . DATUM) to ALIST."
 933   (cons (cons key datum) alist))
 934
 935 (defun pairlis (keys data &optional (alist '()))
 936   #!+sb-doc
 937   "Construct an association list from KEYS and DATA (adding to ALIST)."
 938   (do ((x keys (cdr x))
 939        (y data (cdr y)))
 940       ((and (endp x) (endp y)) alist)
 941     (if (or (endp x) (endp y))
 942         (error "The lists of keys and data are of unequal length."))
 943     (setq alist (acons (car x) (car y) alist))))
 944
 945 ;;; This is defined in the run-time environment, not just the compile-time
 946 ;;; environment (i.e. not wrapped in EVAL-WHEN (COMPILE EVAL)) because it
 947 ;;; can appear in inline expansions.
 948 (defmacro assoc-guts (test-expr)
 949   `(do ((alist alist (cdr alist)))
 950        ((endp alist))
 951     (when (and (car alist) ,test-expr)
 952       (return (car alist)))))
 953
 954 (defun assoc (item alist &key key (test nil testp) (test-not nil notp))
 955   #!+sb-doc
 956   "Return the cons in ALIST whose car is equal (by a given test or EQL) to
 957    the ITEM."
 958   (when (and testp notp)
 959     (error ":TEST and :TEST-NOT were both supplied."))
 960   (let ((key (and key (%coerce-callable-to-fun key)))
 961         (test (and testp (%coerce-callable-to-fun test)))
 962         (test-not (and notp (%coerce-callable-to-fun test-not))))
 963     (cond (test
 964            (if key
 965                (assoc-guts (funcall test item (funcall key (caar alist))))
 966                (assoc-guts (funcall test item (caar alist)))))
 967           (test-not
 968            (if key
 969                (assoc-guts (not (funcall test-not item
 970                                          (funcall key (caar alist)))))
 971                (assoc-guts (not (funcall test-not item (caar alist))))))
 972           (t
 973            (if key
 974                (assoc-guts (eql item (funcall key (caar alist))))
 975                (assoc-guts (eql item (caar alist))))))))
 976
 977 (defun assoc-if (predicate alist &key key)
 978   #!+sb-doc
 979   "Return the first cons in ALIST whose CAR satisfies PREDICATE. If
 980    KEY is supplied, apply it to the CAR of each cons before testing."
 981   (let ((predicate (%coerce-callable-to-fun predicate))
 982         (key (and key (%coerce-callable-to-fun key))))
 983     (if key
 984         (assoc-guts (funcall predicate (funcall key (caar alist))))
 985         (assoc-guts (funcall predicate (caar alist))))))
 986
 987 (defun assoc-if-not (predicate alist &key key)
 988   #!+sb-doc
 989   "Return the first cons in ALIST whose CAR does not satisfy PREDICATE.
 990   If KEY is supplied, apply it to the CAR of each cons before testing."
 991   (let ((predicate (%coerce-callable-to-fun predicate))
 992         (key (and key (%coerce-callable-to-fun key))))
 993     (if key
 994         (assoc-guts (not (funcall predicate (funcall key (caar alist)))))
 995         (assoc-guts (not (funcall predicate (caar alist)))))))
 996
 997 (defun rassoc (item alist &key key (test nil testp) (test-not nil notp))
 998   (declare (list alist))
 999   #!+sb-doc
1000   "Return the cons in ALIST whose CDR is equal (by a given test or EQL) to
1001    the ITEM."
1002   (when (and testp notp)
1003     (error ":TEST and :TEST-NOT were both supplied."))
1004   (let ((key (and key (%coerce-callable-to-fun key)))
1005         (test (and testp (%coerce-callable-to-fun test)))
1006         (test-not (and notp (%coerce-callable-to-fun test-not))))
1007     (cond (test
1008            (if key
1009                (assoc-guts (funcall test item (funcall key (cdar alist))))
1010                (assoc-guts (funcall test item (cdar alist)))))
1011           (test-not
1012            (if key
1013                (assoc-guts (not (funcall test-not item
1014                                          (funcall key (cdar alist)))))
1015                (assoc-guts (not (funcall test-not item (cdar alist))))))
1016           (t
1017            (if key
1018                (assoc-guts (eql item (funcall key (cdar alist))))
1019                (assoc-guts (eql item (cdar alist))))))))
1020
1021 (defun rassoc-if (predicate alist &key key)
1022   #!+sb-doc
1023   "Return the first cons in ALIST whose CDR satisfies PREDICATE. If KEY
1024   is supplied, apply it to the CDR of each cons before testing."
1025   (let ((predicate (%coerce-callable-to-fun predicate))
1026         (key (and key (%coerce-callable-to-fun key))))
1027     (if key
1028         (assoc-guts (funcall predicate (funcall key (cdar alist))))
1029         (assoc-guts (funcall predicate (cdar alist))))))
1030
1031 (defun rassoc-if-not (predicate alist &key key)
1032   #!+sb-doc
1033   "Return the first cons in ALIST whose CDR does not satisfy PREDICATE.
1034   If KEY is supplied, apply it to the CDR of each cons before testing."
1035   (let ((predicate (%coerce-callable-to-fun predicate))
1036         (key (and key (%coerce-callable-to-fun key))))
1037     (if key
1038         (assoc-guts (not (funcall predicate (funcall key (cdar alist)))))
1039         (assoc-guts (not (funcall predicate (cdar alist)))))))
1040 \f
1041 ;;;; mapping functions
1042
1043 ;;; a helper function for implementation of MAPC, MAPCAR, MAPCAN,
1044 ;;; MAPL, MAPLIST, and MAPCON
1045 ;;;
1046 ;;; Map the designated function over the arglists in the appropriate
1047 ;;; way. It is done when any of the arglists runs out. Until then, it
1048 ;;; CDRs down the arglists calling the function and accumulating
1049 ;;; results as desired.
1050 (defun map1 (fun-designator original-arglists accumulate take-car)
1051   (let ((fun (%coerce-callable-to-fun fun-designator)))
1052     (let* ((arglists (copy-list original-arglists))
1053            (ret-list (list nil))
1054            (temp ret-list))
1055       (do ((res nil)
1056            (args '() '()))
1057           ((dolist (x arglists nil) (if (null x) (return t)))
1058            (if accumulate
1059                (cdr ret-list)
1060                (car original-arglists)))
1061         (do ((l arglists (cdr l)))
1062             ((null l))
1063           (push (if take-car (caar l) (car l)) args)
1064           (setf (car l) (cdar l)))
1065         (setq res (apply fun (nreverse args)))
1066         (case accumulate
1067           (:nconc (setq temp (last (nconc temp res))))
1068           (:list (rplacd temp (list res))
1069                  (setq temp (cdr temp))))))))
1070
1071 (defun mapc (function list &rest more-lists)
1072   #!+sb-doc
1073   "Apply FUNCTION to successive elements of lists. Return the second argument."
1074   (map1 function (cons list more-lists) nil t))
1075
1076 (defun mapcar (function list &rest more-lists)
1077   #!+sb-doc
1078   "Apply FUNCTION to successive elements of LIST. Return list of FUNCTION
1079    return values."
1080   (map1 function (cons list more-lists) :list t))
1081
1082 (defun mapcan (function list &rest more-lists)
1083   #!+sb-doc
1084   "Apply FUNCTION to successive elements of LIST. Return NCONC of FUNCTION
1085    results."
1086   (map1 function (cons list more-lists) :nconc t))
1087
1088 (defun mapl (function list &rest more-lists)
1089   #!+sb-doc
1090   "Apply FUNCTION to successive CDRs of list. Return NIL."
1091   (map1 function (cons list more-lists) nil nil))
1092
1093 (defun maplist (function list &rest more-lists)
1094   #!+sb-doc
1095   "Apply FUNCTION to successive CDRs of list. Return list of results."
1096   (map1 function (cons list more-lists) :list nil))
1097
1098 (defun mapcon (function list &rest more-lists)
1099   #!+sb-doc
1100   "Apply FUNCTION to successive CDRs of lists. Return NCONC of results."
1101   (map1 function (cons list more-lists) :nconc nil))