175 lines
4.6 KiB
Prolog
175 lines
4.6 KiB
Prolog
/**
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@defgroup pathconf Configuration of the Prolog file search path
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@ingroup AbsoluteFileName
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Prolog systems search follow a complex search on order to track down files.
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@{
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**/
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/**
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@pred library_directory(?Directory:atom) is nondet, dynamic
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Dynamic, multi-file predicate that succeeds when _Directory_ is a
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current library directory name. Asserted in the user module.
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Library directories are the places where files specified in the form
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`library( _File_ )` are searched by the predicates consult/1,
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reconsult/1, use_module/1, ensure_loaded/1, and load_files/2.
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This directory is initialized by a rule that calls the system predicate
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system_library/1.
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*/
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:- multifile library_directory/1.
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:- dynamic library_directory/1.
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%% Specifies the set of directories where
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% one can find Prolog libraries.
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%
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% 1. honor YAPSHAREDIR
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library_directory( Dir ) :-
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getenv( 'YAPSHAREDIR', Dir).
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%% 2. honor user-library
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library_directory( '~/share/Yap' ).
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%% 3. honor current directory
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library_directory( '.' ).
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%% 4. honor default location.
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library_directory( Dir ) :-
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system_library( Dir ).
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/**
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@pred commons_directory(? _Directory_:atom) is nondet, dynamic
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State the location of the Commons Prolog Initiative.
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This directory is initialized as a rule that calls the system predicate
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library_directories/2.
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:- dynamic commons_directory/1.
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commons_directory( Path ):-
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system_commons( Path ).
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/**
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@pred foreign_directory(? _Directory_:atom) is nondet, dynamic
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State the location of the Foreign Prolog Initiative.
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This directory is initialized as a rule that calls the system predicate
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library_directories/2.
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*/
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:- multifile foreign_directory/1.
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:- dynamic foreign_directory/1.
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foreign_directory( Path ):-
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system_foreign( Path ).
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/**
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@pred prolog_file_type(?Suffix:atom, ?Handler:atom) is nondet, dynamic
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This multifile/dynamic predicate relates a file extension _Suffix_
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to a language or file type _Handler_. By
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default, it supports the extensions yap, pl, and prolog for prolog files and
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uses one of dll, so, or dylib for shared objects. Initial definition is:
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~prolog
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prolog_file_type(yap, prolog).
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prolog_file_type(pl, prolog).
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prolog_file_type(prolog, prolog).
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prolog_file_type(qly, prolog).
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prolog_file_type(qly, qly).
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prolog_file_type(A, prolog) :-
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current_prolog_flag(associate, A),
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A \== prolog,
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A \==pl,
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A \== yap.
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prolog_file_type(A, executable) :-
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current_prolog_flag(shared_object_extension, A).
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*/
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:- multifile prolog_file_type/2.
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:- dynamic prolog_file_type/2.
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prolog_file_type(yap, prolog).
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prolog_file_type(pl, prolog).
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prolog_file_type(prolog, prolog).
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prolog_file_type(A, prolog) :-
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current_prolog_flag(associate, A),
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A \== prolog,
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A \== pl,
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A \== yap.
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prolog_file_type(qly, qly).
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prolog_file_type(A, executable) :-
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current_prolog_flag(shared_object_extension, A).
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/**
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@pred file_search_path(+Name:atom, -Directory:atom) is nondet
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Allows writing file names as compound terms. The _Name_ and
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_DIRECTORY_ must be atoms. The predicate may generate multiple
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solutions. The predicate is originally defined as follows:
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~prolog
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file_search_path(library, Dir) :-
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library_directory(Dir).
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file_search_path(commons, Dir) :-
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commons_directory(Dir).
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file_search_path(swi, Home) :-
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current_prolog_flag(home, Home).
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file_search_path(yap, Home) :-
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current_prolog_flag(home, Home).
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file_search_path(system, Dir) :-
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prolog_flag(host_type, Dir).
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file_search_path(foreign, Dir) :-
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foreign_directory(Dir).
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file_search_path(path, C) :-
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( getenv('PATH', A),
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( current_prolog_flag(windows, true)
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-> atomic_list_concat(B, ;, A)
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; atomic_list_concat(B, :, A)
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),
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lists:member(C, B)
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).
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Thus, `compile(library(A))` will search for a file using
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library_directory/1 to obtain the prefix,
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whereas 'compile(system(A))` would look at the `host_type` flag.
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*/
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:- module(user).
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:- multifile file_search_path/2.
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:- dynamic file_search_path/2.
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file_search_path(library, Dir) :-
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library_directory(Dir).
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file_search_path(commons, Dir) :-
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commons_directory(Dir).
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file_search_path(swi, Home) :-
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current_prolog_flag(home, Home).
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file_search_path(yap, Home) :-
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current_prolog_flag(home, Home).
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file_search_path(system, Dir) :-
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prolog_flag(host_type, Dir).
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file_search_path(foreign, '.').
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file_search_path(foreign, yap('lib/Yap')).
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file_search_path(path, C) :-
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( getenv('PATH', A),
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( current_prolog_flag(windows, true)
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-> atomic_list_concat(B, ;, A)
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; atomic_list_concat(B, :, A)
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),
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lists:member(C, B)
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).
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:- module(prolog).
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%% @}
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