1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker and Anjo Anjewierden 4 E-mail: J.Wielemaker@vu.nl 5 WWW: http://www.swi-prolog.org/ 6 Copyright (c) 2011-2015, University of Amsterdam 7 VU University 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(prolog_breakpoints, 37 [ set_breakpoint/4, % +File, +Line, +CharPos, -Id 38 set_breakpoint/5, % +Owner, +File, +Line, +CharPos, -Id 39 delete_breakpoint/1, % +Id 40 breakpoint_property/2 % ?Id, ?Property 41 ]). 42:- use_module(prolog_clause). 43:- use_module(library(debug)). 44:- use_module(library(error)).
61:- dynamic 62 user:prolog_event_hook/1. 63:- multifile 64 user:prolog_event_hook/1.
First, '$clause_from_source'/4 uses the SWI-Prolog clause-source information to find the last clause starting before Line. '$break_pc' generated (on backtracking), a list of possible break-points.
Note that in addition to setting the break-point, the system must be in debug mode. With threading enabled, there are various different ways this may be done. See debug/0, tdebug/0 and tdebug/1. Therefore, this predicate does not enable debug mode.
90set_breakpoint(File, Line, Char, Id) :- 91 set_breakpoint(File, File, Line, Char, Id). 92set_breakpoint(Owner, File, Line, Char, Id) :- 93 debug(break, 'break_at(~q, ~d, ~d).', [File, Line, Char]), 94 '$clause_from_source'(Owner, File, Line, ClauseRef), 95 clause_info(ClauseRef, InfoFile, TermPos, _NameOffset), 96 ( InfoFile == File 97 -> '$break_pc'(ClauseRef, PC, NextPC), 98 debug(break, 'Clause ~p, PC=~p NextPC=~p', [ClauseRef, PC, NextPC]), 99 '$clause_term_position'(ClauseRef, NextPC, List), 100 debug(break, 'Location = ~w', [List]), 101 range(List, TermPos, _0A, Z), 102 debug(break, 'Term from ~w-~w', [_0A, Z]), 103 Z >= Char, ! 104 ; format('Failed to unify clause ~p, using first break', 105 [ClauseRef]), 106 '$break_pc'(ClauseRef, PC, _), ! 107 ), 108 debug(break, 'Break at clause ~w, PC=~w', [ClauseRef, PC]), 109 with_mutex('$break', next_break_id(Id)), 110 Location = file_position(File, Line, Char), 111 asserta(known_breakpoint(ClauseRef, PC, Location, Id), Ref), 112 catch('$break_at'(ClauseRef, PC, true), E, 113 (erase(Ref), throw(E))). 114 115 116range(_, Pos, _, _) :- 117 var(Pos), !, fail. 118range([], Pos, A, Z) :- 119 arg(1, Pos, A), 120 arg(2, Pos, Z). 121range([H|T], term_position(_, _, _, _, PosL), A, Z) :- 122 nth1(H, PosL, Pos), 123 range(T, Pos, A, Z). 124 125:- dynamic 126 known_breakpoint/4, % 127 break_id/1. 128 129next_break_id(Id) :- 130 retract(break_id(Id0)), 131 !, 132 Id is Id0+1, 133 asserta(break_id(Id)). 134next_break_id(1) :- 135 asserta(break_id(1)).
print_message(breakpoint(delete, Id)) is called. Message hooks
working on this message may still call breakpoint_property/2.
145delete_breakpoint(Id) :- 146 integer(Id), 147 known_breakpoint(ClauseRef, PC, _Location, Id), 148 !, 149 '$break_at'(ClauseRef, PC, false). 150delete_breakpoint(Id) :- 151 existence_error(breakpoint, Id).
169breakpoint_property(Id, file(File)) :- 170 known_breakpoint(ClauseRef,_,_,Id), 171 clause_property(ClauseRef, file(File)). 172breakpoint_property(Id, line_count(Line)) :- 173 known_breakpoint(_,_,Location,Id), 174 location_line(Location, Line). 175breakpoint_property(Id, character_range(Start, Len)) :- 176 known_breakpoint(ClauseRef,PC,_,Id), 177 ( known_breakpoint(_,_,file_character_range(Start,Len),Id) 178 ; break_location(ClauseRef, PC, _File, Start-End), 179 Len is End+1-Start 180 ). 181breakpoint_property(Id, clause(Reference)) :- 182 known_breakpoint(Reference,_,_,Id). 183 184location_line(file_position(_File, Line, _Char), Line). 185location_line(file_character_range(File, Start, _Len), Line) :- 186 file_line(File, Start, Line). 187location_line(file_line(_File, Line), Line).
195file_line(File, Start, Line) :- 196 setup_call_cleanup( 197 open(File, read, In), 198 stream_line(In, Start, 1, Line), 199 close(In)). 200 201stream_line(In, _, Line0, Line) :- 202 at_end_of_stream(In), 203 !, 204 Line = Line0. 205stream_line(In, Index, Line0, Line) :- 206 skip(In, 0'\n), 207 character_count(In, At), 208 ( At > Index 209 -> Line = Line0 210 ; Line1 is Line0+1, 211 stream_line(In, Index, Line1, Line) 212 ). 213 214 215 /******************************* 216 * FEEDBACK * 217 *******************************/ 218 219user:prolog_event_hook(break(ClauseRef, PC, Set)) :- 220 break(Set, ClauseRef, PC). 221 222break(true, ClauseRef, PC) :- 223 known_breakpoint(ClauseRef, PC, _Location, Id), 224 !, 225 print_message(informational, breakpoint(set, Id)). 226break(true, ClauseRef, PC) :- 227 !, 228 debug(break, 'Trap in Clause ~p, PC ~d', [ClauseRef, PC]), 229 with_mutex('$break', next_break_id(Id)), 230 ( break_location(ClauseRef, PC, File, A-Z) 231 -> Len is Z+1-A, 232 Location = file_character_range(File, A, Len) 233 ; clause_property(ClauseRef, file(File)), 234 clause_property(ClauseRef, line_count(Line)) 235 -> Location = file_line(File, Line) 236 ; Location = unknown 237 ), 238 asserta(known_breakpoint(ClauseRef, PC, Location, Id)), 239 print_message(informational, breakpoint(set, Id)). 240break(false, ClauseRef, PC) :- 241 debug(break, 'Remove breakpoint from ~p, PC ~d', [ClauseRef, PC]), 242 clause(known_breakpoint(ClauseRef, PC, _Location, Id), true, Ref), 243 call_cleanup(print_message(informational, breakpoint(delete, Id)), 244 erase(Ref)).
254break_location(ClauseRef, PC, File, A-Z) :- 255 clause_info(ClauseRef, File, TermPos, _NameOffset), 256 '$fetch_vm'(ClauseRef, PC, NPC, _VMI), 257 '$clause_term_position'(ClauseRef, NPC, List), 258 debug(break, 'ClausePos = ~w', [List]), 259 range(List, TermPos, A, Z), 260 debug(break, 'Range: ~d .. ~d', [A, Z]). 261 262 263 /******************************* 264 * MESSAGES * 265 *******************************/ 266 267:- multifile 268 prolog:message/3. 269 270prologmessage(breakpoint(SetClear, Id)) --> 271 setclear(SetClear), 272 breakpoint(Id). 273 274setclear(set) --> 275 ['Breakpoint ']. 276setclear(delete) --> 277 ['Deleted breakpoint ']. 278 279breakpoint(Id) --> 280 breakpoint_name(Id), 281 ( { breakpoint_property(Id, file(File)), 282 file_base_name(File, Base), 283 breakpoint_property(Id, line_count(Line)) 284 } 285 -> [ ' at ~w:~d'-[Base, Line] ] 286 ; [] 287 ). 288 289breakpoint_name(Id) --> 290 { breakpoint_property(Id, clause(ClauseRef)) }, 291 ( { clause_property(ClauseRef, erased) } 292 -> ['~w'-[Id]] 293 ; { clause_name(ClauseRef, Name) }, 294 ['~w in ~w'-[Id, Name]] 295 )
Manage Prolog break-points
This module provides an interface for development tools to set and delete break-points, giving a location in the source. Development tools that want to track changes to breakpoints must use user:message_hook/3 to intercept these message terms:
breakpoint(set, Id)breakpoint(delete, Id)Note that the hook must fail after creating its side-effects to give other hooks the opportunity to react. */