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) 2011-2018, 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(prolog_autoload, 37 [ autoload/0, 38 autoload/1 % +Options 39 ]). 40:- use_module(library(option)). 41:- use_module(library(error)). 42:- use_module(library(aggregate)). 43:- use_module(library(prolog_codewalk)). 44:- use_module(library(check), [ list_undefined/0 ]). 45 46:- predicate_options(autoload/1, 1, 47 [ verbose(boolean), 48 undefined(oneof([ignore,error])) 49 ]).

Autoload all dependencies

The autoloader is there to smoothen program development. It liberates the programmer from finding the library that defines some particular predicate and including the proper use_module/1,2 directive in the sources. This is even better at the toplevel, where just using maplist/3 is way more comfortable than first having to load library(apply). In addition, it reduces the startup time of applications by only loading the necessary bits.

Of course, there is also a price. One is that it becomes less obvious from where some predicate is loaded and thus whether you have the right definition. The second issue is that it is harder to create a stand-alone executable because this executable, without access to the development system, can no longer rely on autoloading. Finally, program analysis becomes harder because the program may be incomplete.

This library provides autoload/0 and autoload/1 to autoload all predicates that are referenced by the program. Now, this is not possible in Prolog because the language allows for constructing arbitrary goals and runtime and calling them (e.g., read(X), call(X)).

The implementation relies on code analysis of the bodies of all clauses and all initialization goals. */

92autoload :- 93 autoload([]). 94 95autoload(Options) :- 96 must_be(list, Options), 97 statistics(cputime, T0), 98 aggregate_all(count, source_file(_), OldFileCount), 99 call_cleanup( 100 autoload(0, Iterations, Options), 101 check:collect_undef(Undef)), 102 aggregate_all(count, source_file(_), NewFileCount), 103 statistics(cputime, T1), 104 Time is T1-T0, 105 information_level(Level, Options), 106 NewFiles is NewFileCount - OldFileCount, 107 print_message(Level, autoload(completed(Iterations, Time, NewFiles))), 108 report_undefined(Undef). 109 110autoload(Iteration0, Iterations, Options) :- 111 statistics(cputime, T0), 112 autoload_step(NewFiles, NewPreds, Options), 113 statistics(cputime, T1), 114 Time is T1-T0, 115 succ(Iteration0, Iteration), 116 ( NewFiles > 0 117 -> information_level(Level, Options), 118 print_message(Level, autoload(reiterate(Iteration, 119 NewFiles, NewPreds, Time))), 120 autoload(Iteration, Iterations, Options) 121 ; Iterations = Iteration 122 ). 123 124information_level(Level, Options) :- 125 ( option(verbose(true), Options) 126 -> Level = informational 127 ; Level = silent 128 ).

139autoload_step(NewFiles, NewPreds, Options) :- 140 option(verbose(Verbose), Options, false), 141 walk_options(Options, WalkOptions), 142 aggregate_all(count, source_file(_), OldFileCount), 143 setup_call_cleanup( 144 ( current_prolog_flag(autoload, OldAutoLoad), 145 current_prolog_flag(verbose_autoload, OldVerbose), 146 set_prolog_flag(autoload, true), 147 set_prolog_flag(verbose_autoload, Verbose), 148 assert_autoload_hook(Ref), 149 asserta(autoloaded_count(0)) 150 ), 151 prolog_walk_code(WalkOptions), 152 ( retract(autoloaded_count(Count)), 153 erase(Ref), 154 set_prolog_flag(autoload, OldAutoLoad), 155 set_prolog_flag(verbose_autoload, OldVerbose) 156 )), 157 aggregate_all(count, source_file(_), NewFileCount), 158 NewPreds = Count, 159 NewFiles is NewFileCount - OldFileCount. 160 161assert_autoload_hook(Ref) :- 162 asserta((user:message_hook(autoload(Module:Name/Arity, Library), _, _) :- 163 autoloaded(Module:Name/Arity, Library)), Ref). 164 165:- public 166 autoloaded/2. 167 168autoloaded(_, _) :- 169 retract(autoloaded_count(N)), 170 succ(N, N2), 171 asserta(autoloaded_count(N2)), 172 fail. % proceed with other hooks

181walk_options([], []). 182walk_options([verbose(V)|T0], [verbose(V)|T]) :- 183 !, 184 walk_options(T0, T). 185walk_options([undefined(error)|T0], 186 [ undefined(trace), 187 on_trace(check:found_undef) 188 | T 189 ]) :- 190 !, 191 walk_options(T0, T). 192walk_options([_|T0], T) :- 193 walk_options(T0, T).

200report_undefined([]) :- 201 !. 202report_undefined(Grouped) :- 203 existence_error(procedures, Grouped). 204 205 206 /******************************* 207 * MESSAGES * 208 *******************************/ 209 210:- multifile 211 prolog:message//1, 212 prolog:error_message//1. 213 214prolog:message(autoload(reiterate(Iteration, NewFiles, NewPreds, Time))) --> 215 [ 'Autoloader: iteration ~D resolved ~D predicates \c 216 and loaded ~D files in ~3f seconds. Restarting ...'- 217 [Iteration, NewPreds, NewFiles, Time] 218 ]. 219prolog:message(autoload(completed(Iterations, Time, NewFiles))) --> 220 [ 'Autoloader: loaded ~D files in ~D iterations in ~3f seconds'- 221 [NewFiles, Iterations, Time] ]. 222 223prolog:error_message(existence_error(procedures, Grouped)) --> 224 prolog:message(check(undefined_procedures, Grouped))

`NewFiles`	- is unified to the number of files loaded
`NewPreds`	- is unified to the number of predicates imported using the autoloader.