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yap-6.3/pl/pathconf.yap
2016-08-02 18:25:39 -05:00

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4.6 KiB
Prolog

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