| 1 | ;;+----------------------------------------------------------------------------- |
|---|
| 2 | ;;+ Isidorus |
|---|
| 3 | ;;+ (c) 2008-2009 Marc Kuester, Christoph Ludwig, Lukas Giessmann |
|---|
| 4 | ;;+ |
|---|
| 5 | ;;+ Isidorus is freely distributable under the LGPL license. |
|---|
| 6 | ;;+ You can find a detailed description in trunk/docs/LGPL-LICENSE.txt. |
|---|
| 7 | ;;+----------------------------------------------------------------------------- |
|---|
| 8 | |
|---|
| 9 | |
|---|
| 10 | (in-package :datamodel) |
|---|
| 11 | |
|---|
| 12 | (defun get-all-revisions () |
|---|
| 13 | "Returns an ordered set of the start dates of all revisions in the engine" |
|---|
| 14 | ;TODO: this is a very inefficient implementation... it would equally |
|---|
| 15 | ;be possible to have a separate object that stored all such |
|---|
| 16 | ;revisions and only make the search from the latest version that's |
|---|
| 17 | ;stored their |
|---|
| 18 | (let ((revision-set)) |
|---|
| 19 | (dolist (vi (elephant:get-instances-by-class 'VersionInfoC)) |
|---|
| 20 | (pushnew (start-revision vi) revision-set)) |
|---|
| 21 | (sort revision-set #'<))) |
|---|
| 22 | |
|---|
| 23 | |
|---|
| 24 | (defun get-all-revisions-for-tm (tm-id) |
|---|
| 25 | "Returns an ordered set of the start dates of all revisions in the |
|---|
| 26 | engine for this Topic Map" |
|---|
| 27 | (let* |
|---|
| 28 | ((tm (get-item-by-item-identifier tm-id :revision 0)) |
|---|
| 29 | (tops-and-assocs (when tm (union (topics tm) (associations tm)))) |
|---|
| 30 | (revision-set nil)) |
|---|
| 31 | (dolist (vi (mapcan #'versions tops-and-assocs)) |
|---|
| 32 | (pushnew (start-revision vi) revision-set)) |
|---|
| 33 | (sort revision-set #'<))) |
|---|
| 34 | |
|---|
| 35 | |
|---|
| 36 | (defgeneric find-all-associations (instance &key revision) |
|---|
| 37 | (:documentation "Finds all associations for a topic.") |
|---|
| 38 | (:method ((instance TopicC) &key (revision *TM-REVISION*)) |
|---|
| 39 | (declare (type (or integer null) revision)) |
|---|
| 40 | (remove-duplicates |
|---|
| 41 | (map 'list #'(lambda(role) |
|---|
| 42 | (parent role :revision revision)) |
|---|
| 43 | (player-in-roles instance :revision revision))))) |
|---|
| 44 | |
|---|
| 45 | |
|---|
| 46 | (defgeneric find-associations (instance &key revision) |
|---|
| 47 | (:documentation "Finds all associations of this topic except |
|---|
| 48 | type-instance-associations.") |
|---|
| 49 | (:method ((instance TopicC) &key (revision *TM-REVISION*)) |
|---|
| 50 | (declare (type (or integer null) revision)) |
|---|
| 51 | (let ((type-instance-topic |
|---|
| 52 | (d:identified-construct |
|---|
| 53 | (elephant:get-instance-by-value |
|---|
| 54 | 'PersistentIdC 'uri *type-instance-psi*)))) |
|---|
| 55 | (remove-if |
|---|
| 56 | #'(lambda(assoc) |
|---|
| 57 | (eql (instance-of assoc :revision revision) |
|---|
| 58 | type-instance-topic)) |
|---|
| 59 | (find-all-associations instance :revision revision))))) |
|---|
| 60 | |
|---|
| 61 | |
|---|
| 62 | (defgeneric find-referenced-topics (construct &key revision) |
|---|
| 63 | (:documentation "find all the topics that are references from this construct as type, scope or player, as the case may be")) |
|---|
| 64 | |
|---|
| 65 | |
|---|
| 66 | (defmethod find-referenced-topics ((characteristic CharacteristicC) |
|---|
| 67 | &key (revision *TM-REVISION*)) |
|---|
| 68 | "characteristics are scopable + typable + reifiable" |
|---|
| 69 | (append |
|---|
| 70 | (when (reifier characteristic :revision revision) |
|---|
| 71 | (list (reifier characteristic :revision revision))) |
|---|
| 72 | (themes characteristic :revision revision) |
|---|
| 73 | (when (instance-of characteristic :revision revision) |
|---|
| 74 | (list (instance-of characteristic :revision revision))) |
|---|
| 75 | (when (and (typep characteristic 'NameC) |
|---|
| 76 | (variants characteristic :revision revision)) |
|---|
| 77 | (remove-if #'null |
|---|
| 78 | (loop for var in (variants characteristic :revision revision) |
|---|
| 79 | append (find-referenced-topics var :revision revision)))) |
|---|
| 80 | (when (and (typep characteristic 'OccurrenceC) |
|---|
| 81 | (> (length (charvalue characteristic)) 0) |
|---|
| 82 | (eq #\# (elt (charvalue characteristic) 0))) |
|---|
| 83 | (list (get-item-by-id (subseq (charvalue characteristic) 1) |
|---|
| 84 | :revision revision))))) |
|---|
| 85 | |
|---|
| 86 | |
|---|
| 87 | (defmethod find-referenced-topics ((role RoleC) |
|---|
| 88 | &key (revision *TM-REVISION*)) |
|---|
| 89 | (append |
|---|
| 90 | (when (reifier role :revision revision) |
|---|
| 91 | (list (reifier role :revision revision))) |
|---|
| 92 | (list (instance-of role :revision revision)) |
|---|
| 93 | (list (player role :revision revision)))) |
|---|
| 94 | |
|---|
| 95 | |
|---|
| 96 | (defmethod find-referenced-topics ((association AssociationC) |
|---|
| 97 | &key (revision *TM-REVISION*)) |
|---|
| 98 | "associations are scopable + typable" |
|---|
| 99 | (append |
|---|
| 100 | (when (reifier association :revision revision) |
|---|
| 101 | (list (reifier association :revision revision))) |
|---|
| 102 | (list (instance-of association :revision revision)) |
|---|
| 103 | (themes association :revision revision) |
|---|
| 104 | (mapcan #'(lambda(role) |
|---|
| 105 | (find-referenced-topics role :revision revision)) |
|---|
| 106 | (roles association :revision revision)))) |
|---|
| 107 | |
|---|
| 108 | |
|---|
| 109 | (defmethod find-referenced-topics ((top TopicC) |
|---|
| 110 | &key (revision *TM-REVISION*)) |
|---|
| 111 | "Part 1b of the eGov-Share spec states: |
|---|
| 112 | # for each topicname in T export a topic stub for each scope topic |
|---|
| 113 | # for each occurrence in T export a topic stub for the occurrence type (if it exists) |
|---|
| 114 | # for each occurrence in T export a topic stub for each scope topic |
|---|
| 115 | # for each association A in which T plays a role export the association |
|---|
| 116 | # for each association A export a topic stub for the association type |
|---|
| 117 | # for each association A export a topic stub for each topic scope topic |
|---|
| 118 | # for each role R in A export a topic stub for the role type and one for the role player UNLESS the role player is T" |
|---|
| 119 | (remove-duplicates |
|---|
| 120 | (remove |
|---|
| 121 | top |
|---|
| 122 | (append |
|---|
| 123 | (list-instanceOf top :revision revision) |
|---|
| 124 | (mapcan #'(lambda(name) |
|---|
| 125 | (find-referenced-topics name :revision revision)) |
|---|
| 126 | (names top :revision revision)) |
|---|
| 127 | (mapcan #'(lambda(variant) |
|---|
| 128 | (find-referenced-topics variant :revision revision)) |
|---|
| 129 | (mapcan #'variants (names top :revision revision))) |
|---|
| 130 | (mapcan #'(lambda(occ) |
|---|
| 131 | (find-referenced-topics occ :revision revision)) |
|---|
| 132 | (occurrences top :revision revision)) |
|---|
| 133 | (mapcan #'(lambda(assoc) |
|---|
| 134 | (find-referenced-topics assoc :revision revision)) |
|---|
| 135 | (find-associations top :revision revision)))))) |
|---|
| 136 | |
|---|
| 137 | |
|---|
| 138 | (defgeneric initial-version-p (version-info) |
|---|
| 139 | (:documentation "A helper function for changed-p that returns the passed |
|---|
| 140 | version-info object if it is the initial version-info object, |
|---|
| 141 | i.e. it owns the smallest start-revsion of the |
|---|
| 142 | version-construct.") |
|---|
| 143 | (:method ((version-info VersionInfoC)) |
|---|
| 144 | (unless (find-if #'(lambda(vi) |
|---|
| 145 | (< (start-revision vi) (start-revision version-info))) |
|---|
| 146 | (versions (versioned-construct version-info))) |
|---|
| 147 | version-info))) |
|---|
| 148 | |
|---|
| 149 | |
|---|
| 150 | (defgeneric changed-p (construct revision) |
|---|
| 151 | (:documentation "Has the topic map construct changed in a given revision? |
|---|
| 152 | 'Changed' can mean: |
|---|
| 153 | * newly created |
|---|
| 154 | * deletion of an element |
|---|
| 155 | * modified through the addition or removal of identifiers |
|---|
| 156 | * (for associations) modified through the addition or removal of |
|---|
| 157 | identifiers in the association or one of its roles |
|---|
| 158 | * (for topics) modified through the addition or removal of identifiers |
|---|
| 159 | or characteristics |
|---|
| 160 | * (for topics) modified through the addition or removal of an association |
|---|
| 161 | in which it is first player")) |
|---|
| 162 | |
|---|
| 163 | |
|---|
| 164 | (defmethod changed-p ((construct TopicMapConstructC) (revision integer)) |
|---|
| 165 | "changed-p returns nil for TopicMapConstructCs that are not specified |
|---|
| 166 | more detailed. The actual algorithm is processed for all |
|---|
| 167 | VersionedConstructCs." |
|---|
| 168 | (declare (ignorable revision)) |
|---|
| 169 | nil) |
|---|
| 170 | |
|---|
| 171 | |
|---|
| 172 | (defmethod changed-p ((construct PointerC) (revision integer)) |
|---|
| 173 | "Returns t if the PointerC was added to a construct the first |
|---|
| 174 | time in the passed revision" |
|---|
| 175 | (let ((version-info (some #'(lambda(pointer-association) |
|---|
| 176 | (changed-p pointer-association revision)) |
|---|
| 177 | (slot-p construct 'identified-construct)))) |
|---|
| 178 | (when version-info |
|---|
| 179 | (initial-version-p version-info)))) |
|---|
| 180 | |
|---|
| 181 | |
|---|
| 182 | (defmethod changed-p ((construct VersionedConstructC) (revision integer)) |
|---|
| 183 | "changed-p returns t if there exist a VersionInfoC with the given start-revision." |
|---|
| 184 | (let ((version-info |
|---|
| 185 | (find revision (versions construct) :test #'= :key #'start-revision))) |
|---|
| 186 | (when version-info |
|---|
| 187 | (initial-version-p version-info)))) |
|---|
| 188 | |
|---|
| 189 | |
|---|
| 190 | (defmethod changed-p ((construct CharacteristicC) (revision integer)) |
|---|
| 191 | "Returns t if the CharacteristicC was added to a construct in the passed |
|---|
| 192 | revision or if <ReifiableConstructC> changed." |
|---|
| 193 | (or (call-next-method) |
|---|
| 194 | (let ((version-info |
|---|
| 195 | (some #'(lambda(characteristic-association) |
|---|
| 196 | (changed-p characteristic-association revision)) |
|---|
| 197 | (slot-p construct 'parent)))) |
|---|
| 198 | (when version-info |
|---|
| 199 | (initial-version-p version-info))))) |
|---|
| 200 | |
|---|
| 201 | |
|---|
| 202 | (defmethod changed-p ((construct RoleC) (revision integer)) |
|---|
| 203 | "Returns t if the RoleC was added to a construct in the passed |
|---|
| 204 | revision or if <ReifiableConstructC> changed." |
|---|
| 205 | (or (call-next-method) |
|---|
| 206 | (let ((version-info |
|---|
| 207 | (some #'(lambda(role-association) |
|---|
| 208 | (changed-p role-association revision)) |
|---|
| 209 | (slot-p construct 'parent)))) |
|---|
| 210 | (when version-info |
|---|
| 211 | (initial-version-p version-info))))) |
|---|
| 212 | |
|---|
| 213 | |
|---|
| 214 | (defgeneric end-revision-p (construct revision) |
|---|
| 215 | (:documentation "A helper function for changed-p. It returns the latest |
|---|
| 216 | version-info if the passed versioned-construct was |
|---|
| 217 | marked-as-deleted in the version that is given.") |
|---|
| 218 | (:method ((construct VersionedConstructC) (revision integer)) |
|---|
| 219 | (let ((version-info (find revision (versions construct) |
|---|
| 220 | :key #'end-revision :test #'=))) |
|---|
| 221 | (when (and version-info |
|---|
| 222 | (not |
|---|
| 223 | (find-if |
|---|
| 224 | #'(lambda(vi) |
|---|
| 225 | (or (> (end-revision vi) (end-revision version-info)) |
|---|
| 226 | (= (end-revision vi) 0))) |
|---|
| 227 | (versions construct)))) |
|---|
| 228 | version-info)))) |
|---|
| 229 | |
|---|
| 230 | |
|---|
| 231 | (defmethod changed-p ((construct ReifiableConstructC) (revision integer)) |
|---|
| 232 | "Returns t if a ReifiableConstructC changed in the given version, i.e. |
|---|
| 233 | an item-identifier or reifier was added to the construct itself." |
|---|
| 234 | (or (some #'(lambda(vc) |
|---|
| 235 | (changed-p vc revision)) |
|---|
| 236 | (union (item-identifiers construct :revision revision) |
|---|
| 237 | (let ((reifier-top (reifier construct :revision revision))) |
|---|
| 238 | (when reifier-top |
|---|
| 239 | (list reifier-top))))) |
|---|
| 240 | (some #'(lambda(vc) |
|---|
| 241 | (end-revision-p vc revision)) |
|---|
| 242 | (union (slot-p construct 'item-identifiers) |
|---|
| 243 | (slot-p construct 'reifier))))) |
|---|
| 244 | |
|---|
| 245 | |
|---|
| 246 | (defmethod changed-p ((construct NameC) (revision integer)) |
|---|
| 247 | "Returns t if the passed NameC changed in the given version, i.e. |
|---|
| 248 | the <ReifiableConstructC> characteristics or the variants changed." |
|---|
| 249 | (or (call-next-method) |
|---|
| 250 | (some #'(lambda(var) |
|---|
| 251 | (changed-p var revision)) |
|---|
| 252 | (variants construct :revision revision)) |
|---|
| 253 | (some #'(lambda(vc) |
|---|
| 254 | (end-revision-p vc revision)) |
|---|
| 255 | (slot-p construct 'variants)))) |
|---|
| 256 | |
|---|
| 257 | |
|---|
| 258 | (defmethod changed-p ((construct TopicC) (revision integer)) |
|---|
| 259 | "Returns t if the passed TopicC changed in the given version, i.e. |
|---|
| 260 | the <ReifiableConstructC>, <PersistentIdC>, <LocatorC>, <NameC>, |
|---|
| 261 | <OccurrenceC>, <AssociationC> or the reified-construct changed." |
|---|
| 262 | (or (call-next-method) |
|---|
| 263 | (some #'(lambda(vc) |
|---|
| 264 | (changed-p vc revision)) |
|---|
| 265 | (union |
|---|
| 266 | (union |
|---|
| 267 | (union (psis construct :revision revision) |
|---|
| 268 | (locators construct :revision revision)) |
|---|
| 269 | (union (names construct :revision revision) |
|---|
| 270 | (occurrences construct :revision revision))) |
|---|
| 271 | (remove-if-not |
|---|
| 272 | (lambda (assoc) |
|---|
| 273 | (eq (player (first (roles assoc :revision revision)) |
|---|
| 274 | :revision revision) |
|---|
| 275 | construct)) |
|---|
| 276 | (find-all-associations construct :revision revision)))) |
|---|
| 277 | (let ((rc (reified-construct construct :revision revision))) |
|---|
| 278 | (when rc |
|---|
| 279 | (let ((ra (find-if #'(lambda(reifier-assoc) |
|---|
| 280 | (eql (reifiable-construct reifier-assoc) rc)) |
|---|
| 281 | (slot-p construct 'reified-construct)))) |
|---|
| 282 | (changed-p ra revision)))) |
|---|
| 283 | (some #'(lambda(vc) |
|---|
| 284 | (end-revision-p vc revision)) |
|---|
| 285 | (union (union (union (slot-p construct 'psis) |
|---|
| 286 | (slot-p construct 'locators)) |
|---|
| 287 | (union (slot-p construct 'names) |
|---|
| 288 | (slot-p construct 'occurrences))) |
|---|
| 289 | (slot-p construct 'reified-construct))))) |
|---|
| 290 | |
|---|
| 291 | |
|---|
| 292 | |
|---|
| 293 | (defmethod changed-p ((construct AssociationC) (revision integer)) |
|---|
| 294 | "Returns t if the passed AssociationC changed in the given version, i.e. |
|---|
| 295 | the <RoleC> or the <ReifiableConstructC> changed." |
|---|
| 296 | (or (call-next-method) |
|---|
| 297 | (some #'(lambda(role) |
|---|
| 298 | (changed-p role revision)) |
|---|
| 299 | (roles construct :revision revision)) |
|---|
| 300 | (some #'(lambda(vc) |
|---|
| 301 | (end-revision-p vc revision)) |
|---|
| 302 | (slot-p construct 'roles)))) |
|---|
| 303 | |
|---|
| 304 | |
|---|
| 305 | (defpclass FragmentC () |
|---|
| 306 | ((revision :type integer |
|---|
| 307 | :initarg :revision |
|---|
| 308 | :accessor revision |
|---|
| 309 | :index t |
|---|
| 310 | :documentation "revision in question") |
|---|
| 311 | (unique-id :initarg :unique-id |
|---|
| 312 | :accessor unique-id |
|---|
| 313 | :index t |
|---|
| 314 | :documentation "a unique id for this fragment. for now |
|---|
| 315 | just its OID, but may become a true UUID in the future") |
|---|
| 316 | (topic :type TopicC |
|---|
| 317 | :initarg :topic |
|---|
| 318 | :accessor topic |
|---|
| 319 | :index t |
|---|
| 320 | :documentation "changed topic (topicSI in Atom") |
|---|
| 321 | (referenced-topics |
|---|
| 322 | :type list |
|---|
| 323 | :initarg :referenced-topics |
|---|
| 324 | :accessor referenced-topics |
|---|
| 325 | :documentation "list of topics that this topic references somehow (through associations, types, scopes in the characteristics etc.") |
|---|
| 326 | (associations |
|---|
| 327 | :type list |
|---|
| 328 | :initarg :associations |
|---|
| 329 | :accessor associations |
|---|
| 330 | :documentation "list of association that this topic is a player in"))) |
|---|
| 331 | |
|---|
| 332 | (defmethod initialize-instance :after ((fragment FragmentC) &key) |
|---|
| 333 | "initialze the unique id of the fragment ot some suitable value" |
|---|
| 334 | (setf (slot-value fragment 'unique-id) (elephant::oid fragment))) |
|---|
| 335 | |
|---|
| 336 | |
|---|
| 337 | (defun get-fragments (revision) |
|---|
| 338 | "Gets the list of all fragments for a given revision. Returns a |
|---|
| 339 | list of FragmentC objects" |
|---|
| 340 | (declare (integer revision)) |
|---|
| 341 | (let |
|---|
| 342 | ((cached-fragments |
|---|
| 343 | (elephant:get-instances-by-value 'FragmentC |
|---|
| 344 | 'revision |
|---|
| 345 | revision))) |
|---|
| 346 | (if cached-fragments |
|---|
| 347 | cached-fragments |
|---|
| 348 | (remove |
|---|
| 349 | nil |
|---|
| 350 | (map |
|---|
| 351 | 'list |
|---|
| 352 | (lambda (top) |
|---|
| 353 | (when (changed-p top revision) |
|---|
| 354 | (make-instance 'FragmentC |
|---|
| 355 | :revision revision |
|---|
| 356 | :associations (find-associations |
|---|
| 357 | top :revision revision) |
|---|
| 358 | ;TODO: this quite probably introduces |
|---|
| 359 | ;code duplication with query: Check! |
|---|
| 360 | :referenced-topics (find-referenced-topics |
|---|
| 361 | top :revision revision) |
|---|
| 362 | :topic top))) |
|---|
| 363 | (get-all-topics revision)))))) |
|---|
| 364 | |
|---|
| 365 | (defun get-fragment (unique-id) |
|---|
| 366 | "get a fragment by its unique id" |
|---|
| 367 | (declare (integer unique-id)) |
|---|
| 368 | (elephant:get-instance-by-value 'FragmentC |
|---|
| 369 | 'unique-id |
|---|
| 370 | unique-id)) |
|---|
| 371 | |
|---|
| 372 | (defgeneric add-source-locator (construct &key source-locator revision) |
|---|
| 373 | (:documentation "adds an item identifier to a given construct based on the source |
|---|
| 374 | locator and an internally generated id (ideally a uuid)")) |
|---|
| 375 | |
|---|
| 376 | |
|---|
| 377 | (defmethod add-source-locator ((construct ReifiableConstructC) &key source-locator revision) |
|---|
| 378 | (declare (integer revision)) |
|---|
| 379 | (unless |
|---|
| 380 | (some (lambda (ii) |
|---|
| 381 | (string-starts-with (uri ii) source-locator)) |
|---|
| 382 | (item-identifiers construct :revision revision)) |
|---|
| 383 | (let |
|---|
| 384 | ((ii-uri (format nil "~a/~d" source-locator (internal-id construct)))) |
|---|
| 385 | (make-construct 'ItemIdentifierC |
|---|
| 386 | :uri ii-uri |
|---|
| 387 | :identified-construct construct |
|---|
| 388 | :start-revision revision)))) |
|---|
| 389 | |
|---|
| 390 | |
|---|
| 391 | (defmethod add-source-locator ((top TopicC) &key source-locator revision) |
|---|
| 392 | ;topics already have the source locator in (at least) one PSI, so we |
|---|
| 393 | ;do not need to add an extra item identifier to them. However, we |
|---|
| 394 | ;need to do that for all their characteristics + associations |
|---|
| 395 | (mapc (lambda (name) |
|---|
| 396 | (add-source-locator name :revision revision |
|---|
| 397 | :source-locator source-locator)) |
|---|
| 398 | (names top :revision revision)) |
|---|
| 399 | (mapc (lambda (occ) |
|---|
| 400 | (add-source-locator occ :revision revision |
|---|
| 401 | :source-locator source-locator)) |
|---|
| 402 | (occurrences top :revision revision)) |
|---|
| 403 | (mapc (lambda (ass) |
|---|
| 404 | (add-source-locator ass :revision revision |
|---|
| 405 | :source-locator source-locator)) |
|---|
| 406 | (find-associations top :revision revision))) |
|---|
| 407 | |
|---|
| 408 | |
|---|
| 409 | (defun create-latest-fragment-of-topic (topic-psi) |
|---|
| 410 | "Returns the latest fragment of the passed topic-psi" |
|---|
| 411 | (declare (string topic-psi)) |
|---|
| 412 | (let ((topic (get-latest-topic-by-psi topic-psi))) |
|---|
| 413 | (when topic |
|---|
| 414 | (let ((start-revision |
|---|
| 415 | (start-revision |
|---|
| 416 | (find-if #'(lambda(x) |
|---|
| 417 | (when (= 0 (end-revision x)) |
|---|
| 418 | t)) |
|---|
| 419 | (versions topic))))) |
|---|
| 420 | (let ((existing-fragment |
|---|
| 421 | (find-if #'(lambda(x) |
|---|
| 422 | (when (eq topic (topic x)) |
|---|
| 423 | t)) |
|---|
| 424 | (get-fragments start-revision)))) |
|---|
| 425 | (if existing-fragment |
|---|
| 426 | existing-fragment |
|---|
| 427 | (make-instance 'FragmentC |
|---|
| 428 | :revision start-revision |
|---|
| 429 | :associations (find-associations |
|---|
| 430 | topic :revision start-revision) |
|---|
| 431 | :referenced-topics (find-referenced-topics |
|---|
| 432 | topic :revision start-revision) |
|---|
| 433 | :topic topic))))))) |
|---|
| 434 | |
|---|
| 435 | |
|---|
| 436 | (defun get-latest-fragment-of-topic (topic-psi) |
|---|
| 437 | "Returns the latest existing fragment of the passed topic-psi." |
|---|
| 438 | (declare (string topic-psi)) |
|---|
| 439 | (let ((topic (get-latest-topic-by-psi topic-psi))) |
|---|
| 440 | (when topic |
|---|
| 441 | (let ((existing-fragments |
|---|
| 442 | (elephant:get-instances-by-value 'FragmentC 'topic topic))) |
|---|
| 443 | (when existing-fragments |
|---|
| 444 | (first (sort existing-fragments |
|---|
| 445 | #'(lambda(frg-1 frg-2) |
|---|
| 446 | (> (revision frg-1) (revision frg-2)))))))))) |
|---|
