lists.lisp - clic - Clic is an command line interactive client for gopher written in Common LISP (HTM) git clone git://bitreich.org/clic/ git://enlrupgkhuxnvlhsf6lc3fziv5h2hhfrinws65d7roiv6bfj7d652fid.onion/clic/ (DIR) Log (DIR) Files (DIR) Refs (DIR) Tags (DIR) README (DIR) LICENSE --- lists.lisp (14160B) --- 1 (in-package :alexandria) 2 3 (declaim (inline safe-endp)) 4 (defun safe-endp (x) 5 (declare (optimize safety)) 6 (endp x)) 7 8 (defun alist-plist (alist) 9 "Returns a property list containing the same keys and values as the 10 association list ALIST in the same order." 11 (let (plist) 12 (dolist (pair alist) 13 (push (car pair) plist) 14 (push (cdr pair) plist)) 15 (nreverse plist))) 16 17 (defun plist-alist (plist) 18 "Returns an association list containing the same keys and values as the 19 property list PLIST in the same order." 20 (let (alist) 21 (do ((tail plist (cddr tail))) 22 ((safe-endp tail) (nreverse alist)) 23 (push (cons (car tail) (cadr tail)) alist)))) 24 25 (declaim (inline racons)) 26 (defun racons (key value ralist) 27 (acons value key ralist)) 28 29 (macrolet 30 ((define-alist-get (name get-entry get-value-from-entry add doc) 31 `(progn 32 (declaim (inline ,name)) 33 (defun ,name (alist key &key (test 'eql)) 34 ,doc 35 (let ((entry (,get-entry key alist :test test))) 36 (values (,get-value-from-entry entry) entry))) 37 (define-setf-expander ,name (place key &key (test ''eql) 38 &environment env) 39 (multiple-value-bind 40 (temporary-variables initforms newvals setter getter) 41 (get-setf-expansion place env) 42 (when (cdr newvals) 43 (error "~A cannot store multiple values in one place" ',name)) 44 (with-unique-names (new-value key-val test-val alist entry) 45 (values 46 (append temporary-variables 47 (list alist 48 key-val 49 test-val 50 entry)) 51 (append initforms 52 (list getter 53 key 54 test 55 `(,',get-entry ,key-val ,alist :test ,test-val))) 56 `(,new-value) 57 `(cond 58 (,entry 59 (setf (,',get-value-from-entry ,entry) ,new-value)) 60 (t 61 (let ,newvals 62 (setf ,(first newvals) (,',add ,key ,new-value ,alist)) 63 ,setter 64 ,new-value))) 65 `(,',get-value-from-entry ,entry)))))))) 66 (define-alist-get assoc-value assoc cdr acons 67 "ASSOC-VALUE is an alist accessor very much like ASSOC, but it can 68 be used with SETF.") 69 (define-alist-get rassoc-value rassoc car racons 70 "RASSOC-VALUE is an alist accessor very much like RASSOC, but it can 71 be used with SETF.")) 72 73 (defun malformed-plist (plist) 74 (error "Malformed plist: ~S" plist)) 75 76 (defmacro doplist ((key val plist &optional values) &body body) 77 "Iterates over elements of PLIST. BODY can be preceded by 78 declarations, and is like a TAGBODY. RETURN may be used to terminate 79 the iteration early. If RETURN is not used, returns VALUES." 80 (multiple-value-bind (forms declarations) (parse-body body) 81 (with-gensyms (tail loop results) 82 `(block nil 83 (flet ((,results () 84 (let (,key ,val) 85 (declare (ignorable ,key ,val)) 86 (return ,values)))) 87 (let* ((,tail ,plist) 88 (,key (if ,tail 89 (pop ,tail) 90 (,results))) 91 (,val (if ,tail 92 (pop ,tail) 93 (malformed-plist ',plist)))) 94 (declare (ignorable ,key ,val)) 95 ,@declarations 96 (tagbody 97 ,loop 98 ,@forms 99 (setf ,key (if ,tail 100 (pop ,tail) 101 (,results)) 102 ,val (if ,tail 103 (pop ,tail) 104 (malformed-plist ',plist))) 105 (go ,loop)))))))) 106 107 (define-modify-macro appendf (&rest lists) append 108 "Modify-macro for APPEND. Appends LISTS to the place designated by the first 109 argument.") 110 111 (define-modify-macro nconcf (&rest lists) nconc 112 "Modify-macro for NCONC. Concatenates LISTS to place designated by the first 113 argument.") 114 115 (define-modify-macro unionf (list &rest args) union 116 "Modify-macro for UNION. Saves the union of LIST and the contents of the 117 place designated by the first argument to the designated place.") 118 119 (define-modify-macro nunionf (list &rest args) nunion 120 "Modify-macro for NUNION. Saves the union of LIST and the contents of the 121 place designated by the first argument to the designated place. May modify 122 either argument.") 123 124 (define-modify-macro reversef () reverse 125 "Modify-macro for REVERSE. Copies and reverses the list stored in the given 126 place and saves back the result into the place.") 127 128 (define-modify-macro nreversef () nreverse 129 "Modify-macro for NREVERSE. Reverses the list stored in the given place by 130 destructively modifying it and saves back the result into the place.") 131 132 (defun circular-list (&rest elements) 133 "Creates a circular list of ELEMENTS." 134 (let ((cycle (copy-list elements))) 135 (nconc cycle cycle))) 136 137 (defun circular-list-p (object) 138 "Returns true if OBJECT is a circular list, NIL otherwise." 139 (and (listp object) 140 (do ((fast object (cddr fast)) 141 (slow (cons (car object) (cdr object)) (cdr slow))) 142 (nil) 143 (unless (and (consp fast) (listp (cdr fast))) 144 (return nil)) 145 (when (eq fast slow) 146 (return t))))) 147 148 (defun circular-tree-p (object) 149 "Returns true if OBJECT is a circular tree, NIL otherwise." 150 (labels ((circularp (object seen) 151 (and (consp object) 152 (do ((fast (cons (car object) (cdr object)) (cddr fast)) 153 (slow object (cdr slow))) 154 (nil) 155 (when (or (eq fast slow) (member slow seen)) 156 (return-from circular-tree-p t)) 157 (when (or (not (consp fast)) (not (consp (cdr slow)))) 158 (return 159 (do ((tail object (cdr tail))) 160 ((not (consp tail)) 161 nil) 162 (let ((elt (car tail))) 163 (circularp elt (cons object seen)))))))))) 164 (circularp object nil))) 165 166 (defun proper-list-p (object) 167 "Returns true if OBJECT is a proper list." 168 (cond ((not object) 169 t) 170 ((consp object) 171 (do ((fast object (cddr fast)) 172 (slow (cons (car object) (cdr object)) (cdr slow))) 173 (nil) 174 (unless (and (listp fast) (consp (cdr fast))) 175 (return (and (listp fast) (not (cdr fast))))) 176 (when (eq fast slow) 177 (return nil)))) 178 (t 179 nil))) 180 181 (deftype proper-list () 182 "Type designator for proper lists. Implemented as a SATISFIES type, hence 183 not recommended for performance intensive use. Main usefullness as a type 184 designator of the expected type in a TYPE-ERROR." 185 `(and list (satisfies proper-list-p))) 186 187 (defun circular-list-error (list) 188 (error 'type-error 189 :datum list 190 :expected-type '(and list (not circular-list)))) 191 192 (macrolet ((def (name lambda-list doc step declare ret1 ret2) 193 (assert (member 'list lambda-list)) 194 `(defun ,name ,lambda-list 195 ,doc 196 (unless (listp list) 197 (error 'type-error :datum list :expected-type 'list)) 198 (do ((last list fast) 199 (fast list (cddr fast)) 200 (slow (cons (car list) (cdr list)) (cdr slow)) 201 ,@(when step (list step))) 202 (nil) 203 (declare (dynamic-extent slow) ,@(when declare (list declare)) 204 (ignorable last)) 205 (when (safe-endp fast) 206 (return ,ret1)) 207 (when (safe-endp (cdr fast)) 208 (return ,ret2)) 209 (when (eq fast slow) 210 (circular-list-error list)))))) 211 (def proper-list-length (list) 212 "Returns length of LIST, signalling an error if it is not a proper list." 213 (n 1 (+ n 2)) 214 ;; KLUDGE: Most implementations don't actually support lists with bignum 215 ;; elements -- and this is WAY faster on most implementations then declaring 216 ;; N to be an UNSIGNED-BYTE. 217 (fixnum n) 218 (1- n) 219 n) 220 221 (def lastcar (list) 222 "Returns the last element of LIST. Signals a type-error if LIST is not a 223 proper list." 224 nil 225 nil 226 (cadr last) 227 (car fast)) 228 229 (def (setf lastcar) (object list) 230 "Sets the last element of LIST. Signals a type-error if LIST is not a proper 231 list." 232 nil 233 nil 234 (setf (cadr last) object) 235 (setf (car fast) object))) 236 237 (defun make-circular-list (length &key initial-element) 238 "Creates a circular list of LENGTH with the given INITIAL-ELEMENT." 239 (let ((cycle (make-list length :initial-element initial-element))) 240 (nconc cycle cycle))) 241 242 (deftype circular-list () 243 "Type designator for circular lists. Implemented as a SATISFIES type, so not 244 recommended for performance intensive use. Main usefullness as the 245 expected-type designator of a TYPE-ERROR." 246 `(satisfies circular-list-p)) 247 248 (defun ensure-car (thing) 249 "If THING is a CONS, its CAR is returned. Otherwise THING is returned." 250 (if (consp thing) 251 (car thing) 252 thing)) 253 254 (defun ensure-cons (cons) 255 "If CONS is a cons, it is returned. Otherwise returns a fresh cons with CONS 256 in the car, and NIL in the cdr." 257 (if (consp cons) 258 cons 259 (cons cons nil))) 260 261 (defun ensure-list (list) 262 "If LIST is a list, it is returned. Otherwise returns the list designated by LIST." 263 (if (listp list) 264 list 265 (list list))) 266 267 (defun remove-from-plist (plist &rest keys) 268 "Returns a propery-list with same keys and values as PLIST, except that keys 269 in the list designated by KEYS and values corresponding to them are removed. 270 The returned property-list may share structure with the PLIST, but PLIST is 271 not destructively modified. Keys are compared using EQ." 272 (declare (optimize (speed 3))) 273 ;; FIXME: possible optimization: (remove-from-plist '(:x 0 :a 1 :b 2) :a) 274 ;; could return the tail without consing up a new list. 275 (loop for (key . rest) on plist by #'cddr 276 do (assert rest () "Expected a proper plist, got ~S" plist) 277 unless (member key keys :test #'eq) 278 collect key and collect (first rest))) 279 280 (defun delete-from-plist (plist &rest keys) 281 "Just like REMOVE-FROM-PLIST, but this version may destructively modify the 282 provided PLIST." 283 (declare (optimize speed)) 284 (loop with head = plist 285 with tail = nil ; a nil tail means an empty result so far 286 for (key . rest) on plist by #'cddr 287 do (assert rest () "Expected a proper plist, got ~S" plist) 288 (if (member key keys :test #'eq) 289 ;; skip over this pair 290 (let ((next (cdr rest))) 291 (if tail 292 (setf (cdr tail) next) 293 (setf head next))) 294 ;; keep this pair 295 (setf tail rest)) 296 finally (return head))) 297 298 (define-modify-macro remove-from-plistf (&rest keys) remove-from-plist 299 "Modify macro for REMOVE-FROM-PLIST.") 300 (define-modify-macro delete-from-plistf (&rest keys) delete-from-plist 301 "Modify macro for DELETE-FROM-PLIST.") 302 303 (declaim (inline sans)) 304 (defun sans (plist &rest keys) 305 "Alias of REMOVE-FROM-PLIST for backward compatibility." 306 (apply #'remove-from-plist plist keys)) 307 308 (defun mappend (function &rest lists) 309 "Applies FUNCTION to respective element(s) of each LIST, appending all the 310 all the result list to a single list. FUNCTION must return a list." 311 (loop for results in (apply #'mapcar function lists) 312 append results)) 313 314 (defun setp (object &key (test #'eql) (key #'identity)) 315 "Returns true if OBJECT is a list that denotes a set, NIL otherwise. A list 316 denotes a set if each element of the list is unique under KEY and TEST." 317 (and (listp object) 318 (let (seen) 319 (dolist (elt object t) 320 (let ((key (funcall key elt))) 321 (if (member key seen :test test) 322 (return nil) 323 (push key seen))))))) 324 325 (defun set-equal (list1 list2 &key (test #'eql) (key nil keyp)) 326 "Returns true if every element of LIST1 matches some element of LIST2 and 327 every element of LIST2 matches some element of LIST1. Otherwise returns false." 328 (let ((keylist1 (if keyp (mapcar key list1) list1)) 329 (keylist2 (if keyp (mapcar key list2) list2))) 330 (and (dolist (elt keylist1 t) 331 (or (member elt keylist2 :test test) 332 (return nil))) 333 (dolist (elt keylist2 t) 334 (or (member elt keylist1 :test test) 335 (return nil)))))) 336 337 (defun map-product (function list &rest more-lists) 338 "Returns a list containing the results of calling FUNCTION with one argument 339 from LIST, and one from each of MORE-LISTS for each combination of arguments. 340 In other words, returns the product of LIST and MORE-LISTS using FUNCTION. 341 342 Example: 343 344 (map-product 'list '(1 2) '(3 4) '(5 6)) 345 => ((1 3 5) (1 3 6) (1 4 5) (1 4 6) 346 (2 3 5) (2 3 6) (2 4 5) (2 4 6)) 347 " 348 (labels ((%map-product (f lists) 349 (let ((more (cdr lists)) 350 (one (car lists))) 351 (if (not more) 352 (mapcar f one) 353 (mappend (lambda (x) 354 (%map-product (curry f x) more)) 355 one))))) 356 (%map-product (ensure-function function) (cons list more-lists)))) 357 358 (defun flatten (tree) 359 "Traverses the tree in order, collecting non-null leaves into a list." 360 (let (list) 361 (labels ((traverse (subtree) 362 (when subtree 363 (if (consp subtree) 364 (progn 365 (traverse (car subtree)) 366 (traverse (cdr subtree))) 367 (push subtree list))))) 368 (traverse tree)) 369 (nreverse list)))