/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@vu.nl
WWW: http://www.swi-prolog.org
Copyright (c) 1985-2020, University of Amsterdam
VU University Amsterdam
CWI, Amsterdam
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
:- module('$autoload',
[ '$find_library'/5,
'$in_library'/3,
'$define_predicate'/1,
'$update_library_index'/0,
'$autoload'/1,
make_library_index/1,
make_library_index/2,
reload_library_index/0,
autoload_path/1,
autoload/1, % +File
autoload/2, % +File, +Imports
require/1 % +Predicates
]).
:- meta_predicate
'$autoload'(:),
autoload(:),
autoload(:, +),
require(:).
:- dynamic
library_index/3, % Head x Module x Path
autoload_directories/1, % List
index_checked_at/1. % Time
:- volatile
library_index/3,
autoload_directories/1,
index_checked_at/1.
user:file_search_path(autoload, swi(library)).
user:file_search_path(autoload, pce(prolog/lib)).
user:file_search_path(autoload, app_config(lib)).
%! '$find_library'(+Module, +Name, +Arity, -LoadModule, -Library) is semidet.
%
% Locate a predicate in the library. Name and arity are the name
% and arity of the predicate searched for. `Module' is the
% preferred target module. The return values are the full path
% name (excluding extension) of the library and module declared in
% that file.
'$find_library'(Module, Name, Arity, LoadModule, Library) :-
load_library_index(Name, Arity),
functor(Head, Name, Arity),
( library_index(Head, Module, Library),
LoadModule = Module
; library_index(Head, LoadModule, Library)
),
!.
%! '$in_library'(+Name, +Arity, -Path) is semidet.
%! '$in_library'(-Name, -Arity, -Path) is nondet.
%
% Is true if Name/Arity is in the autoload libraries.
'$in_library'(Name, Arity, Path) :-
atom(Name), integer(Arity),
!,
load_library_index(Name, Arity),
functor(Head, Name, Arity),
library_index(Head, _, Path).
'$in_library'(Name, Arity, Path) :-
load_library_index(Name, Arity),
library_index(Head, _, Path),
functor(Head, Name, Arity).
%! '$define_predicate'(:Head)
%
% Make sure PredInd can be called. First test if the predicate is
% defined. If not, invoke the autoloader.
:- meta_predicate
'$define_predicate'(:).
'$define_predicate'(Head) :-
'$defined_predicate'(Head),
!.
'$define_predicate'(Term) :-
Term = Module:Head,
( compound(Head)
-> compound_name_arity(Head, Name, Arity)
; Name = Head, Arity = 0
),
'$undefined_procedure'(Module, Name, Arity, retry).
/********************************
* UPDATE INDEX *
********************************/
:- thread_local
silent/0.
%! '$update_library_index'
%
% Called from make/0 to update the index of the library for each
% library directory that has a writable index. Note that in the
% Windows version access_file/2 is mostly bogus. We assert
% silent/0 to suppress error messages.
'$update_library_index' :-
setof(Dir, writable_indexed_directory(Dir), Dirs),
!,
setup_call_cleanup(
asserta(silent, Ref),
guarded_make_library_index(Dirs),
erase(Ref)),
( flag('$modified_index', true, false)
-> reload_library_index
; true
).
'$update_library_index'.
guarded_make_library_index([]).
guarded_make_library_index([Dir|Dirs]) :-
( catch(make_library_index(Dir), E,
print_message(error, E))
-> true
; print_message(warning, goal_failed(make_library_index(Dir)))
),
guarded_make_library_index(Dirs).
%! writable_indexed_directory(-Dir) is nondet.
%
% True when Dir is an indexed library directory with a writable
% index, i.e., an index that can be updated.
writable_indexed_directory(Dir) :-
index_file_name(IndexFile, autoload('INDEX'), [access([read,write])]),
file_directory_name(IndexFile, Dir).
writable_indexed_directory(Dir) :-
absolute_file_name(library('MKINDEX'),
[ file_type(prolog),
access(read),
solutions(all),
file_errors(fail)
], MkIndexFile),
file_directory_name(MkIndexFile, Dir),
plfile_in_dir(Dir, 'INDEX', _, IndexFile),
access_file(IndexFile, write).
/********************************
* LOAD INDEX *
********************************/
%! reload_library_index
%
% Reload the index on the next call
reload_library_index :-
context_module(M),
reload_library_index(M).
reload_library_index(M) :-
with_mutex('$autoload', clear_library_index(M)).
clear_library_index(M) :-
retractall(M:library_index(_, _, _)),
retractall(M:autoload_directories(_)),
retractall(M:index_checked_at(_)).
%! load_library_index(?Name, ?Arity) is det.
%! load_library_index(?Name, ?Arity, :IndexSpec) is det.
%
% Try to find Name/Arity in the library. If the predicate is
% there, we are happy. If not, we check whether the set of loaded
% libraries has changed and if so we reload the index.
:- meta_predicate load_library_index(?, ?, :).
:- public load_library_index/3.
load_library_index(Name, Arity) :-
load_library_index(Name, Arity, autoload('INDEX')).
load_library_index(Name, Arity, M:_Spec) :-
atom(Name), integer(Arity),
functor(Head, Name, Arity),
M:library_index(Head, _, _),
!.
load_library_index(_, _, Spec) :-
notrace(with_mutex('$autoload', load_library_index_p(Spec))).
load_library_index_p(M:_) :-
M:index_checked_at(Time),
get_time(Now),
Now-Time < 60,
!.
load_library_index_p(M:Spec) :-
findall(Index, index_file_name(Index, Spec, [access(read)]), List0),
'$list_to_set'(List0, List),
retractall(M:index_checked_at(_)),
get_time(Now),
assert(M:index_checked_at(Now)),
( M:autoload_directories(List)
-> true
; retractall(M:library_index(_, _, _)),
retractall(M:autoload_directories(_)),
read_index(List, M),
assert(M:autoload_directories(List))
).
%! index_file_name(-IndexFile, +Spec, +Options) is nondet.
%
% True if IndexFile is an autoload index file. Options is passed
% to absolute_file_name/3. This predicate searches the path
% =autoload=.
%
% @see file_search_path/2.
index_file_name(IndexFile, FileSpec, Options) :-
absolute_file_name(FileSpec,
IndexFile,
[ file_type(prolog),
solutions(all),
file_errors(fail)
| Options
]).
read_index([], _) :- !.
read_index([H|T], M) :-
!,
read_index(H, M),
read_index(T, M).
read_index(Index, M) :-
print_message(silent, autoload(read_index(Dir))),
file_directory_name(Index, Dir),
setup_call_cleanup(
'$push_input_context'(autoload_index),
setup_call_cleanup(
open(Index, read, In),
read_index_from_stream(Dir, In, M),
close(In)),
'$pop_input_context').
read_index_from_stream(Dir, In, M) :-
repeat,
read(In, Term),
assert_index(Term, Dir, M),
!.
assert_index(end_of_file, _, _) :- !.
assert_index(index(Name, Arity, Module, File), Dir, M) :-
!,
functor(Head, Name, Arity),
atomic_list_concat([Dir, '/', File], Path),
assertz(M:library_index(Head, Module, Path)),
fail.
assert_index(Term, Dir, _) :-
print_message(error, illegal_autoload_index(Dir, Term)),
fail.
/********************************
* CREATE INDEX.pl *
********************************/
%! make_library_index(+Dir) is det.
%
% Create an index for autoloading from the directory Dir. The
% index file is called INDEX.pl. In Dir contains a file
% MKINDEX.pl, this file is loaded and we assume that the index is
% created by directives that appearin this file. Otherwise, all
% source files are scanned for their module-header and all
% exported predicates are added to the autoload index.
%
% @see make_library_index/2
make_library_index(Dir0) :-
forall(absolute_file_name(Dir0, Dir,
[ expand(true),
file_type(directory),
file_errors(fail),
solutions(all)
]),
make_library_index2(Dir)).
make_library_index2(Dir) :-
plfile_in_dir(Dir, 'MKINDEX', _MkIndex, AbsMkIndex),
access_file(AbsMkIndex, read),
!,
load_files(user:AbsMkIndex, [silent(true)]).
make_library_index2(Dir) :-
findall(Pattern, source_file_pattern(Pattern), PatternList),
make_library_index2(Dir, PatternList).
%! make_library_index(+Dir, +Patterns:list(atom)) is det.
%
% Create an autoload index INDEX.pl for Dir by scanning all files
% that match any of the file-patterns in Patterns. Typically, this
% appears as a directive in MKINDEX.pl. For example:
%
% ```
% :- prolog_load_context(directory, Dir),
% make_library_index(Dir, ['*.pl']).
% ```
%
% @see make_library_index/1.
make_library_index(Dir0, Patterns) :-
forall(absolute_file_name(Dir0, Dir,
[ expand(true),
file_type(directory),
file_errors(fail),
solutions(all)
]),
make_library_index2(Dir, Patterns)).
make_library_index2(Dir, Patterns) :-
plfile_in_dir(Dir, 'INDEX', _Index, AbsIndex),
ensure_slash(Dir, DirS),
pattern_files(Patterns, DirS, Files),
( library_index_out_of_date(AbsIndex, Files)
-> do_make_library_index(AbsIndex, DirS, Files),
flag('$modified_index', _, true)
; true
).
ensure_slash(Dir, DirS) :-
( sub_atom(Dir, _, _, 0, /)
-> DirS = Dir
; atom_concat(Dir, /, DirS)
).
source_file_pattern(Pattern) :-
user:prolog_file_type(PlExt, prolog),
PlExt \== qlf,
atom_concat('*.', PlExt, Pattern).
plfile_in_dir(Dir, Base, PlBase, File) :-
file_name_extension(Base, pl, PlBase),
atomic_list_concat([Dir, '/', PlBase], File).
pattern_files([], _, []).
pattern_files([H|T], DirS, Files) :-
atom_concat(DirS, H, P0),
expand_file_name(P0, Files0),
'$append'(Files0, Rest, Files),
pattern_files(T, DirS, Rest).
library_index_out_of_date(Index, _Files) :-
\+ exists_file(Index),
!.
library_index_out_of_date(Index, Files) :-
time_file(Index, IndexTime),
( time_file('.', DotTime),
DotTime > IndexTime
; '$member'(File, Files),
time_file(File, FileTime),
FileTime > IndexTime
),
!.
do_make_library_index(Index, Dir, Files) :-
ensure_slash(Dir, DirS),
'$stage_file'(Index, StagedIndex),
setup_call_catcher_cleanup(
open(StagedIndex, write, Out),
( print_message(informational, make(library_index(Dir))),
index_header(Out),
index_files(Files, DirS, Out)
),
Catcher,
install_index(Out, Catcher, StagedIndex, Index)).
install_index(Out, Catcher, StagedIndex, Index) :-
catch(close(Out), Error, true),
( silent
-> OnError = silent
; OnError = error
),
( var(Error)
-> TheCatcher = Catcher
; TheCatcher = exception(Error)
),
'$install_staged_file'(TheCatcher, StagedIndex, Index, OnError).
%! index_files(+Files, +Directory, +Out:stream) is det.
%
% Write index for Files in Directory to the stream Out.
index_files([], _, _).
index_files([File|Files], DirS, Fd) :-
catch(setup_call_cleanup(
open(File, read, In),
read(In, Term),
close(In)),
E, print_message(warning, E)),
( Term = (:- module(Module, Public)),
is_list(Public)
-> atom_concat(DirS, Local, File),
file_name_extension(Base, _, Local),
forall(public_predicate(Public, Name/Arity),
format(Fd, 'index((~k), ~k, ~k, ~k).~n',
[Name, Arity, Module, Base]))
; true
),
index_files(Files, DirS, Fd).
public_predicate(Public, PI) :-
'$member'(PI0, Public),
canonical_pi(PI0, PI).
canonical_pi(Var, _) :-
var(Var), !, fail.
canonical_pi(Name/Arity, Name/Arity).
canonical_pi(Name//A0, Name/Arity) :-
Arity is A0 + 2.
index_header(Fd):-
format(Fd, '/* Creator: make/0~n~n', []),
format(Fd, ' Purpose: Provide index for autoload~n', []),
format(Fd, '*/~n~n', []).
/*******************************
* EXTENDING *
*******************************/
%! autoload_path(+Path) is det.
%
% Add Path to the libraries that are used by the autoloader. This
% extends the search path =autoload= and reloads the library
% index. For example:
%
% ==
% :- autoload_path(library(http)).
% ==
%
% If this call appears as a directive, it is term-expanded into a
% clause for user:file_search_path/2 and a directive calling
% reload_library_index/0. This keeps source information and allows
% for removing this directive.
autoload_path(Alias) :-
( user:file_search_path(autoload, Alias)
-> true
; assertz(user:file_search_path(autoload, Alias)),
reload_library_index
).
system:term_expansion((:- autoload_path(Alias)),
[ user:file_search_path(autoload, Alias),
(:- reload_library_index)
]).
/*******************************
* RUNTIME AUTOLOADER *
*******************************/
%! $autoload'(:PI) is semidet.
%
% Provide PI by autoloading. This checks:
%
% - Explicit autoload/2 declarations
% - Explicit autoload/1 declarations
% - The library if current_prolog_flag(autoload, true) holds.
'$autoload'(PI) :-
source_location(File, _Line),
!,
setup_call_cleanup(
'$start_aux'(File, Context),
'$autoload2'(PI),
'$end_aux'(File, Context)).
'$autoload'(PI) :-
'$autoload2'(PI).
'$autoload2'(PI) :-
autoload_from(PI, LoadModule, FullFile),
do_autoload(FullFile, PI, LoadModule).
%! autoload_from(+PI, -LoadModule, -File) is semidet.
%
% True when PI can be defined by loading File which is defined the
% module LoadModule.
autoload_from(Module:PI, LoadModule, FullFile) :-
autoload_in(Module, explicit),
current_autoload(Module:File, Ctx, import(Imports)),
memberchk(PI, Imports),
library_info(File, Ctx, FullFile, LoadModule, Exports),
( pi_in_exports(PI, Exports)
-> !
; autoload_error(Ctx, not_exported(PI, File, FullFile, Exports)),
fail
).
autoload_from(Module:Name/Arity, LoadModule, FullFile) :-
autoload_in(Module, explicit),
PI = Name/Arity,
current_autoload(Module:File, Ctx, all),
library_info(File, Ctx, FullFile, LoadModule, Exports),
pi_in_exports(PI, Exports).
autoload_from(Module:Name/Arity, LoadModule, Library) :-
autoload_in(Module, general),
'$find_library'(Module, Name, Arity, LoadModule, Library).
:- public autoload_in/2. % used in syspred
autoload_in(Module, How) :-
current_prolog_flag(autoload, AutoLoad),
autoload_in(AutoLoad, How, Module),
!.
%! autoload_in(+AutoloadFlag, +AutoloadMode, +TargetModule) is semidet.
autoload_in(true, _, _).
autoload_in(explicit, explicit, _).
autoload_in(explicit_or_user, explicit, _).
autoload_in(user, explicit, user).
autoload_in(explicit_or_user, explicit, _).
autoload_in(user, _, user).
autoload_in(explicit_or_user, general, user).
%! do_autoload(+File, :PI, +LoadModule) is det.
%
% Load File, importing PI into the qualified module. File is known to
% define LoadModule.
%
% @tbd: Why do we need LoadModule?
do_autoload(Library, Module:Name/Arity, LoadModule) :-
functor(Head, Name, Arity),
'$update_autoload_level'([autoload(true)], Old),
verbose_autoload(Module:Name/Arity, Library),
'$compilation_mode'(OldComp, database),
( Module == LoadModule
-> ensure_loaded(Module:Library)
; ( '$get_predicate_attribute'(LoadModule:Head, defined, 1),
\+ '$loading'(Library)
-> Module:import(LoadModule:Name/Arity)
; use_module(Module:Library, [Name/Arity])
)
),
'$set_compilation_mode'(OldComp),
'$set_autoload_level'(Old),
'$c_current_predicate'(_, Module:Head).
verbose_autoload(PI, Library) :-
current_prolog_flag(verbose_autoload, true),
!,
set_prolog_flag(verbose_autoload, false),
print_message(informational, autoload(PI, Library)),
set_prolog_flag(verbose_autoload, true).
verbose_autoload(PI, Library) :-
print_message(silent, autoload(PI, Library)).
%! autoloadable(:Head, -File) is nondet.
%
% True when Head can be autoloaded from File. This implements the
% predicate_property/2 property autoload(File). The module muse be
% instantiated.
:- public % used from predicate_property/2
autoloadable/2.
autoloadable(M:Head, FullFile) :-
atom(M),
current_module(M),
autoload_in(M, explicit),
( callable(Head)
-> goal_name_arity(Head, Name, Arity),
autoload_from(M:Name/Arity, _, FullFile)
; findall((M:H)-F, autoloadable_2(M:H, F), Pairs),
( '$member'(M:Head-FullFile, Pairs)
; current_autoload(M:File, Ctx, all),
library_info(File, Ctx, FullFile, _, Exports),
'$member'(PI, Exports),
'$pi_head'(PI, Head),
\+ memberchk(M:Head-_, Pairs)
)
).
autoloadable(M:Head, FullFile) :-
( var(M)
-> autoload_in(any, general)
; autoload_in(M, general)
),
( callable(Head)
-> goal_name_arity(Head, Name, Arity),
( '$find_library'(_, Name, Arity, _, FullFile)
-> true
)
; '$in_library'(Name, Arity, autoload),
functor(Head, Name, Arity)
).
autoloadable_2(M:Head, FullFile) :-
current_autoload(M:File, Ctx, import(Imports)),
library_info(File, Ctx, FullFile, _LoadModule, _Exports),
'$member'(PI, Imports),
'$pi_head'(PI, Head).
goal_name_arity(Head, Name, Arity) :-
compound(Head),
!,
compound_name_arity(Head, Name, Arity).
goal_name_arity(Head, Head, 0).
%! library_info(+Spec, +AutoloadContext, -FullFile, -Module, -Exports)
%
% Find information about a library.
library_info(Spec, _, FullFile, Module, Exports) :-
'$resolved_source_path'(Spec, FullFile, []),
!,
( \+ '$loading_file'(FullFile, _Queue, _LoadThread)
-> '$current_module'(Module, FullFile),
'$module_property'(Module, exports(Exports))
; library_info_from_file(FullFile, Module, Exports)
).
library_info(Spec, Context, FullFile, Module, Exports) :-
( Context = (Path:_Line)
-> Extra = [relative_to(Path)]
; Extra = []
),
( absolute_file_name(Spec, FullFile,
[ file_type(prolog),
access(read),
file_errors(fail)
| Extra
])
-> '$register_resolved_source_path'(Spec, FullFile),
library_info_from_file(FullFile, Module, Exports)
; autoload_error(Context, no_file(Spec)),
fail
).
library_info_from_file(FullFile, Module, Exports) :-
setup_call_cleanup(
'$open_source'(FullFile, In, State, [], []),
'$term_in_file'(In, _Read, _RLayout, Term, _TLayout, _Stream,
[FullFile], []),
'$close_source'(State, true)),
( Term = (:- module(Module, Exports))
-> !
; nonvar(Term),
skip_header(Term)
-> fail
; throw(error(domain_error(module_file, FullFile), _))
).
skip_header(begin_of_file).
:- dynamic printed/3.
:- volatile printed/3.
autoload_error(Context, Error) :-
suppress(Context, Error),
!.
autoload_error(Context, Error) :-
get_time(Now),
assertz(printed(Context, Error, Now)),
print_message(warning, error(autoload(Error), autoload(Context))).
suppress(Context, Error) :-
printed(Context, Error, Printed),
get_time(Now),
( Now - Printed < 1
-> true
; retractall(printed(Context, Error, _)),
fail
).
/*******************************
* CALLBACK *
*******************************/
:- public
set_autoload/1.
%! set_autoload(+Value) is det.
%
% Hook called from set_prolog_flag/2 when autoloading is switched. If
% the desired value is `false` we should materialize all registered
% requests for autoloading. We must do so before disabling autoloading
% as loading the files may require autoloading.
set_autoload(FlagValue) :-
\+ autoload_in(FlagValue, explicit, any),
!,
setup_call_cleanup(
nb_setval('$autoload_disabling', true),
materialize_autoload(Count),
nb_delete('$autoload_disabling')),
print_message(informational, autoload(disabled(Count))).
set_autoload(_).
materialize_autoload(Count) :-
State = state(0),
forall(current_predicate(M:'$autoload'/3),
materialize_autoload(M, State)),
arg(1, State, Count).
materialize_autoload(M, State) :-
( current_autoload(M:File, Context, Import),
library_info(File, Context, FullFile, _LoadModule, _Exports),
arg(1, State, N0),
N is N0+1,
nb_setarg(1, State, N),
( Import == all
-> verbose_autoload(M:all, FullFile),
use_module(M:FullFile)
; Import = import(Preds)
-> verbose_autoload(M:Preds, FullFile),
use_module(M:FullFile, Preds)
),
fail
; true
),
abolish(M:'$autoload'/3).
/*******************************
* AUTOLOAD/2 *
*******************************/
autoload(M:File) :-
( \+ autoload_in(M, explicit)
; nb_current('$autoload_disabling', true)
),
!,
use_module(M:File).
autoload(M:File) :-
'$must_be'(filespec, File),
source_context(Context),
retractall(M:'$autoload'(File, _, _)),
assert_autoload(M:'$autoload'(File, Context, all)).
autoload(M:File, Imports) :-
( \+ autoload_in(M, explicit)
; nb_current('$autoload_disabling', true)
),
!,
use_module(M:File, Imports).
autoload(M:File, Imports0) :-
'$must_be'(filespec, File),
valid_imports(Imports0, Imports),
source_context(Context),
register_autoloads(Imports, M, File, Context),
( current_autoload(M:File, _, import(Imports))
-> true
; assert_autoload(M:'$autoload'(File, Context, import(Imports)))
).
source_context(Path:Line) :-
source_location(Path, Line),
!.
source_context(-).
assert_autoload(Clause) :-
'$initialization_context'(Source, Ctx),
'$store_admin_clause2'(Clause, _Layout, Source, Ctx).
valid_imports(Imports0, Imports) :-
'$must_be'(list, Imports0),
valid_import_list(Imports0, Imports).
valid_import_list([], []).
valid_import_list([H0|T0], [H|T]) :-
'$pi_head'(H0, Head),
'$pi_head'(H, Head),
valid_import_list(T0, T).
%! register_autoloads(+ListOfPI, +Module, +File, +Context)
%
% Put an `autoload` flag on all predicates declared using autoload/2
% to prevent duplicates or the user defining the same predicate.
register_autoloads([], _, _, _).
register_autoloads([PI|T], Module, File, Context) :-
PI = Name/Arity,
functor(Head, Name, Arity),
( '$get_predicate_attribute'(Module:Head, autoload, 1)
-> ( current_autoload(Module:_File0, _Ctx0, import(Imports)),
memberchk(PI, Imports)
-> '$permission_error'(redefine, imported_procedure, PI),
fail
; Done = true
)
; '$get_predicate_attribute'(Module:Head, imported, From)
-> ( ( '$resolved_source_path'(File, FullFile)
-> true
; '$resolve_source_path'(File, FullFile, [])
),
module_property(From, file(FullFile))
-> Done = true
; print_message(warning,
autoload(already_defined(Module:PI, From))),
Done = true
)
; true
),
( Done == true
-> true
; '$set_predicate_attribute'(Module:Head, autoload, 1)
),
register_autoloads(T, Module, File, Context).
pi_in_exports(PI, Exports) :-
'$member'(E, Exports),
canonical_pi(E, PI),
!.
current_autoload(M:File, Context, Term) :-
'$get_predicate_attribute'(M:'$autoload'(_,_,_), defined, 1),
M:'$autoload'(File, Context, Term).
/*******************************
* REQUIRE *
*******************************/
%! require(:ListOfPredIndicators) is det.
%
% Register the predicates in ListOfPredIndicators for autoloading
% using autoload/2 if they are not system predicates.
require(M:Spec) :-
( is_list(Spec)
-> List = Spec
; phrase(comma_list(Spec), List)
), !,
require(List, M, FromLib),
keysort(FromLib, Sorted),
by_file(Sorted, Autoload),
forall('$member'(File-Import, Autoload),
autoload(M:File, Import)).
require(_:Spec) :-
'$type_error'(list, Spec).
require([],_, []).
require([H|T], M, Needed) :-
'$pi_head'(H, Head),
( '$get_predicate_attribute'(system:Head, defined, 1)
-> require(T, M, Needed)
; '$pi_head'(Module:Name/Arity, M:Head),
( '$find_library'(Module, Name, Arity, _LoadModule, Library)
-> Needed = [Library-H|More],
require(T, M, More)
; print_message(error, error(existence_error(procedure, Name/Arity), _)),
require(T, M, Needed)
)
).
by_file([], []).
by_file([File-PI|T0], [Spec-[PI|PIs]|T]) :-
on_path(File, Spec),
same_file(T0, File, PIs, T1),
by_file(T1, T).
on_path(Library, library(Base)) :-
file_base_name(Library, Base),
findall(Path, plain_source(library(Base), Path), [Library]),
!.
on_path(Library, Library).
plain_source(Spec, Path) :-
absolute_file_name(Spec, PathExt,
[ file_type(prolog),
access(read),
file_errors(fail),
solutions(all)
]),
file_name_extension(Path, _, PathExt).
same_file([File-PI|T0], File, [PI|PIs], T) :-
!,
same_file(T0, File, PIs, T).
same_file(List, _, [], List).
comma_list(Var) -->
{ var(Var),
!,
'$instantiation_error'(Var)
}.
comma_list((A,B)) -->
!,
comma_list(A),
comma_list(B).
comma_list(A) -->
[A].