/* Part of SWI-Prolog Author: Jan Wielemaker E-mail: J.Wielemaker@cs.vu.nl WWW: http://www.swi-prolog.org Copyright (C): 2012, VU University Amsterdam This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA As a special exception, if you link this library with other files, compiled with a Free Software compiler, to produce an executable, this library does not by itself cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU General Public License. */ :- module(prolog_autoload, [ autoload/0, autoload/1 % +Options ]). :- use_module(library(option)). :- use_module(library(error)). :- use_module(library(aggregate)). :- use_module(library(prolog_codewalk)). :- predicate_options(autoload/1, 1, [ verbose(boolean), undefined(oneof([ignore,error])) ]). /** 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 classical version relied on the predicate_property =undefined=. The current version relies on code analysis of the bodies of all clauses and all initialization goals. */ :- thread_local autoloaded_count/1. %% autoload is det. %% autoload(+Options) is det. % % Force all necessary autoloading to be done _now_. Options: % % * verbose(+Boolean) % If =true=, report on the files loaded. % * undefined(+Action) % Action defines what happens if the analysis finds a % definitely undefined predicate. One of =ignore= or % =error=. autoload :- autoload([]). autoload(Options) :- must_be(list, Options), statistics(cputime, T0), aggregate_all(count, source_file(_), OldFileCount), autoload(0, Iterations, Options), aggregate_all(count, source_file(_), NewFileCount), statistics(cputime, T1), Time is T1-T0, information_level(Level, Options), NewFiles is NewFileCount - OldFileCount, print_message(Level, autoload(completed(Iterations, Time, NewFiles))). autoload(Iteration0, Iterations, Options) :- statistics(cputime, T0), autoload_step(NewFiles, NewPreds, Options), statistics(cputime, T1), Time is T1-T0, succ(Iteration0, Iteration), ( NewFiles > 0 -> information_level(Level, Options), print_message(Level, autoload(reiterate(Iteration, NewFiles, NewPreds, Time))), autoload(Iteration, Iterations, Options) ; Iterations = Iteration ). information_level(Level, Options) :- ( option(verbose(true), Options, true) -> Level = informational ; Level = silent ). %% autoload_step(-NewFiles, -NewPreds, +Options) is det. % % Scan through the program and autoload all undefined referenced % predicates. % % @param NewFiles is unified to the number of files loaded % @param NewPreds is unified to the number of predicates imported % using the autoloader. autoload_step(NewFiles, NewPreds, Options) :- option(verbose(Verbose), Options, true), aggregate_all(count, source_file(_), OldFileCount), setup_call_cleanup( ( current_prolog_flag(autoload, OldAutoLoad), current_prolog_flag(verbose_autoload, OldVerbose), set_prolog_flag(autoload, true), set_prolog_flag(verbose_autoload, Verbose), assert_autoload_hook(Ref), asserta(autoloaded_count(0)) ), prolog_walk_code(Options), ( retract(autoloaded_count(Count)), erase(Ref), set_prolog_flag(autoload, OldAutoLoad), set_prolog_flag(verbose_autoload, OldVerbose) )), aggregate_all(count, source_file(_), NewFileCount), NewPreds = Count, NewFiles is NewFileCount - OldFileCount. assert_autoload_hook(Ref) :- asserta((user:message_hook(autoload(Module:Name/Arity, Library), _, _) :- autoloaded(Module:Name/Arity, Library)), Ref). :- public autoloaded/2. autoloaded(_, _) :- retract(autoloaded_count(N)), succ(N, N2), asserta(autoloaded_count(N2)), fail. % proceed with other hooks /******************************* * MESSAGES * *******************************/ :- multifile prolog:message//1. prolog:message(autoload(reiterate(Iteration, NewFiles, NewPreds, Time))) --> [ 'Autoloader: iteration ~D resolved ~D predicates \c and loaded ~D files in ~3f seconds. Restarting ...'- [Iteration, NewFiles, NewPreds, Time] ]. prolog:message(autoload(completed(Iterations, Time, NewFiles))) --> [ 'Autoloader: loaded ~D files in ~D iterations in ~3f seconds'- [NewFiles, Iterations, Time] ].