1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker 4 E-mail: J.Wielemaker@vu.nl 5 WWW: http://www.swi-prolog.org 6 Copyright (c) 2019-2020, VU University Amsterdam 7 CWI, Amsterdam 8 All rights reserved. 9 10 Redistribution and use in source and binary forms, with or without 11 modification, are permitted provided that the following conditions 12 are met: 13 14 1. Redistributions of source code must retain the above copyright 15 notice, this list of conditions and the following disclaimer. 16 17 2. Redistributions in binary form must reproduce the above copyright 18 notice, this list of conditions and the following disclaimer in 19 the documentation and/or other materials provided with the 20 distribution. 21 22 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 23 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 24 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 25 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 26 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 27 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 28 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 29 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 30 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 32 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 POSSIBILITY OF SUCH DAMAGE. 34*/ 35 36:- module(tables, 37 [ abolish_all_tables/0, 38 abolish_module_tables/1, % +Module 39 abolish_table_pred/1, % :CallableOrPI 40 abolish_table_call/1, % :Callable 41 abolish_table_call/2, % :Callable, +Options 42 abolish_table_subgoals/2, % :Callable, +Options 43 44 tfindall/3, % +Template, :Goal, -Answers 45 't not'/1, % :Goal 46 47 get_call/3, % :CallTerm, -AnswerTrie, -Templ 48 get_calls/3, % :CallTerm, -AnswerTrie, -Templ 49 get_returns/2, % +AnswerTrie, -Return 50 get_returns/3, % +AnswerTrie, -Return, -NodeID 51 get_returns_and_dls/3, % +AnswerTrie, -Return, -DL 52 get_returns_and_tvs/3, % +AnswerTrie, -Return, -TVs 53 get_returns_for_call/2, % :CallTerm, ?AnswerTerm 54 get_residual/2, % :CallTerm, -DelayList 55 56 set_pil_on/0, 57 set_pil_off/0, 58 59 op(900, fy, tnot) 60 ]). 61:- autoload(library(apply), [maplist/3]). 62:- autoload(library(error), [type_error/2, must_be/2, domain_error/2]). 63:- autoload(library(lists), [append/3]). 64 65/** <module> XSB interface to tables 66 67This module provides an XSB compatible library to access tables as 68created by tabling (see table/1). The aim of this library is first of 69all compatibility with XSB. This library contains some old and internal 70XSB predicates that are marked deprecated. 71*/ 72 73:- meta_predicate 74 abolish_table_pred(:), 75 abolish_table_call(:), 76 abolish_table_call(:, +), 77 abolish_table_subgoals(:, +), 78 tfindall(+, 0, -), 79 't not'(0), 80 get_call(:, -, -), 81 get_calls(:, -, -), 82 get_returns_for_call(:, :), 83 get_returns_and_dls(+, -, :), 84 get_residual(:, -). 85 86%! 't not'(:Goal) 87% 88% Tabled negation. 89% 90% @deprecated This is a synonym to tnot/1. 91 92't not'(Goal) :- 93 tnot(Goal). 94 95%! tfindall(+Template, :Goal, -Answers) 96% 97% This predicate emerged in XSB in an attempt to provide a safer 98% alternative to findall/3. This doesn't really work in XSB and the 99% SWI-Prolog emulation is a simple call to findall/3. Note that Goal 100% may not be a variant of an _incomplete_ table. 101% 102% @deprecated Use findall/3 103 104tfindall(Template, Goal, Answers) :- 105 findall(Template, Goal, Answers). 106 107%! set_pil_on. 108%! set_pil_off. 109% 110% Dummy predicates for XSB compatibility. 111% 112% @deprecated These predicates have no effect. 113 114set_pil_on. 115set_pil_off. 116 117%! get_call(:CallTerm, -Trie, -Return) is semidet. 118% 119% True when Trie is an answer trie for a variant of CallTerm. Return 120% is a term ret/N with N variables that share with variables in 121% CallTerm. The Trie contains zero or more instances of the Return 122% term. See also get_calls/3. 123 124get_call(Goal0, Trie, Return) :- 125 '$tbl_implementation'(Goal0, M:Goal), 126 M:'$table_mode'(Goal, Table, Moded), 127 current_table(M:Table, Trie), 128 '$tbl_table_status'(Trie, _Status, M:Table, Skeleton), 129 extend_return(Moded, Skeleton, Return). 130 131extend_return(Moded, Skeleton, Return) :- 132 '$tbl_trienode'(Reserved), 133 Moded == Reserved, 134 !, 135 Return = Skeleton. 136extend_return(Moded, Skeleton, Return) :- 137 var(Moded), 138 !, 139 Skeleton =.. [ret|Args0], 140 append(Args0, [Moded], Args), 141 Return =.. [ret|Args]. 142extend_return(Moded, Skeleton, Return) :- 143 Moded =.. [_|Extra], 144 Skeleton =.. [ret|Args0], 145 append(Args0, Extra, Args), 146 Return =.. [ret|Args]. 147 148%! get_calls(:CallTerm, -Trie, -Return) is nondet. 149% 150% True when Trie is an answer trie for a variant that unifies with 151% CallTerm and Skeleton is the answer skeleton. See get_call/3 for 152% details. 153 154get_calls(Goal0, Trie, Return) :- 155 '$tbl_variant_table'(VariantTrie), 156 '$tbl_implementation'(Goal0, M:Goal), 157 M:'$table_mode'(Goal, Table, Moded), 158 trie_gen(VariantTrie, M:Table, Trie), 159 '$tbl_table_status'(Trie, _Status, M:Table, Skeleton), 160 extend_return(Moded, Skeleton, Return). 161 162%! get_returns(+ATrie, -Return) is nondet. 163% 164% True when Return is an answer template for the AnswerTrie. 165% 166% @arg Return is a term ret(...). See get_calls/3. 167 168get_returns(ATrie, Return) :- 169 '$tbl_table_status'(ATrie, _Status, M:Table, Skeleton), 170 M:'$table_mode'(_Goal, Table, Moded), 171 '$tbl_trienode'(Reserved), 172 Moded \== Reserved, 173 !, 174 extend_return(Moded, Skeleton, Return), 175 '$tabling':moded_gen_answer(ATrie, Skeleton, Moded). 176get_returns(ATrie, Return) :- 177 trie_gen(ATrie, Return). 178 179%! get_returns(+AnswerTrie, -Return, -NodeID) is nondet. 180% 181% True when Return is an answer template for the AnswerTrie and the 182% answer is represented by the trie node NodeID. 183% 184% @arg Return is a term ret(...). See get_calls/3. 185 186get_returns(AnswerTrie, Return, NodeID) :- 187 '$trie_gen_node'(AnswerTrie, Return, NodeID). 188 189%! get_returns_and_tvs(+AnswerTrie, -Return, -TruthValue) is nondet. 190% 191% Identical to get_returns/2, but also obtains the truth value of a 192% given answer, setting TruthValue to `t` if the answer is 193% unconditional and to `u` if it is conditional. If a conditional 194% answer has multiple delay lists, this predicate will succeed only 195% once, so that using this predicate may be more efficient than 196% get_residual/2 (although less informative) 197 198get_returns_and_tvs(ATrie, Return, TruthValue) :- 199 '$tbl_table_status'(ATrie, _Status, M:Table, Skeleton), 200 M:'$table_mode'(_Goal, Table, Moded), 201 '$tbl_trienode'(Reserved), 202 Moded \== Reserved, 203 !, 204 extend_return(Moded, Skeleton, Return), 205 trie_gen(ATrie, Skeleton), 206 '$tbl_answer_dl'(ATrie, Skeleton, Moded, AN), 207 ( AN == true 208 -> TruthValue = t 209 ; TruthValue = u 210 ). 211get_returns_and_tvs(AnswerTrie, Return, TruthValue) :- 212 '$tbl_answer_dl'(AnswerTrie, Return, AN), 213 ( AN == true 214 -> TruthValue = t 215 ; TruthValue = u 216 ). 217 218%! get_returns_and_dls(+AnswerTrie, -Return, :DelayLists) is nondet. 219% 220% True when Return appears in AnswerTrie with the given DelayLists. 221% DelayLists is a list of lists, where the inner lists expresses a 222% conjunctive condition and and outer list a disjunction. 223 224get_returns_and_dls(AnswerTrie, Return, M:DelayLists) :- 225 '$tbl_answer'(AnswerTrie, Return, Condition), 226 condition_delay_lists(Condition, M, DelayLists). 227 228condition_delay_lists(true, _, []) :- 229 !. 230condition_delay_lists((A;B), M, List) :- 231 !, 232 phrase(semicolon_list((A;B)), L0), 233 maplist(conj_list(M), L0, List). 234condition_delay_lists(One, M, [List]) :- 235 conj_list(M, One, List). 236 237semicolon_list((A;B)) --> 238 !, 239 semicolon_list(A), 240 semicolon_list(B). 241semicolon_list(G) --> 242 [G]. 243 244 245%! get_residual(:CallTerm, -DelayList) is nondet. 246% 247% True if CallTerm appears in a table and has DelayList. SWI-Prolog's 248% representation for a delay is a body term, more specifically a 249% disjunction of conjunctions. The XSB representation is 250% non-deterministic and uses a list to represent the conjunction. 251% 252% The delay condition is a disjunction of conjunctions and is 253% represented as such in the native SWI-Prolog interface as a nested 254% term of ;/2 and ,/2, using `true` if the answer is unconditional. 255% This XSB predicate returns the associated conjunctions 256% non-deterministically as a list. 257% 258% See also call_residual_program/2 from library(wfs). 259 260get_residual(Goal0, DelayList) :- 261 '$tbl_implementation'(Goal0, Goal), 262 Goal = M:Head, 263 '$tbl_trienode'(Reserved), 264 M:'$table_mode'(Head, Variant, Moded), 265 '$tbl_variant_table'(VariantTrie), 266 trie_gen(VariantTrie, M:Variant, Trie), 267 '$tbl_table_status'(Trie, _Status, M:Variant, Skeleton), 268 ( Reserved == Moded 269 -> '$tbl_answer'(Trie, Skeleton, Condition) 270 ; '$tbl_answer'(Trie, Skeleton, Moded, Condition) 271 ), 272 condition_delay_list(Condition, M, DelayList). 273 274condition_delay_list(true, _, List) :- 275 !, 276 List = []. 277condition_delay_list((A;B), M, List) :- 278 !, 279 ( condition_delay_list(A, M, List) 280 ; condition_delay_list(B, M, List) 281 ). 282condition_delay_list(Conj, M, List) :- 283 !, 284 conj_list(M, Conj, List). 285 286conj_list(M, Conj, List) :- 287 phrase(comma_list(Conj, M), List). 288 289comma_list((A,B), M) --> 290 !, 291 comma_list(A, M), 292 comma_list(B, M). 293comma_list(M:G, M) --> 294 !, 295 [G]. 296comma_list(tnot(M:G), M) --> 297 !, 298 [tnot(G)]. 299comma_list(system:G, _) --> 300 !, 301 [G]. 302comma_list(G, _) --> 303 [G]. 304 305 306%! get_returns_for_call(:CallTerm, -AnswerTerm) is nondet. 307% 308% True if AnswerTerm appears in the tables for the _variant_ CallTerm. 309 310get_returns_for_call(CallTerm, M:AnswerTerm) :- 311 current_table(CallTerm, Trie), 312 '$tbl_table_status'(Trie, _Status, Q:AnswerTerm0, Skeleton), 313 ( Q == M 314 -> AnswerTerm = AnswerTerm0 315 ; AnswerTerm = Q:AnswerTerm0 316 ), 317 '$tbl_answer_update_dl'(Trie, Skeleton). 318 319 320 /******************************* 321 * TABLES * 322 *******************************/ 323 324%! abolish_table_pred(:CallTermOrPI) 325% 326% Invalidates all tabled subgoals for the predicate denoted by the 327% predicate or term indicator Pred. 328% 329% @tbd If Pred has a subgoal that contains a conditional answer, the 330% default behavior will be to transitively abolish any tabled 331% predicates with subgoals having answers that depend on any 332% conditional answers of S. 333 334abolish_table_pred(M:Name/Arity) :- 335 !, 336 functor(Head, Name, Arity), 337 abolish_table_subgoals(M:Head). 338abolish_table_pred(M:Head) :- 339 callable(Head), 340 !, 341 functor(Head, Name, Arity), 342 functor(Generic, Name, Arity), 343 abolish_table_subgoals(M:Generic). 344abolish_table_pred(PI) :- 345 type_error(callable_or_predicate_indicator, PI). 346 347%! abolish_table_call(+Head) is det. 348%! abolish_table_call(+Head, +Options) is det. 349% 350% Same as abolish_table_subgoals/1. See also abolish_table_pred/1. 351% 352% @deprecated Use abolish_table_subgoals/[1,2]. 353 354abolish_table_call(Head) :- 355 abolish_table_subgoals(Head). 356 357abolish_table_call(Head, Options) :- 358 abolish_table_subgoals(Head, Options). 359 360%! abolish_table_subgoals(:Head, +Options) 361% 362% Behaves as abolish_table_subgoals/1, but allows the default 363% `table_gc_action` to be over-ridden with a flag, which can be either 364% `abolish_tables_transitively` or `abolish_tables_singly`. 365% 366% @compat Options is compatible with XSB, but does not follow the ISO 367% option handling conventions. 368 369abolish_table_subgoals(Head, Options) :- 370 must_be(list, Options), 371 ( Options == [] 372 -> abolish_table_subgoals(Head) 373 ; memberchk(abolish_tables_transitively, Options) 374 -> abolish_table_subgoals(Head) 375 ; memberchk(abolish_tables_singly, Options) 376 -> abolish_table_subgoals(Head) 377 ; domain_error([abolish_tables_transitively,abolish_tables_singly], Options) 378 ). 379