swi.yap

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/**
  * @file   swi.yap
  * @author VITOR SANTOS COSTA <vsc@VITORs-MBP-2.lan>
  * @date   Thu Oct 19 12:18:05 2017
  * 
  * @brief  SWI Emulation support
  *
  * @ingroup dialects
  * 
  * 
*/
:- module('$swi',
      []).
 
%%  file_alias_path(-Alias, ?Dir) is nondet.
%
%   True if file Alias points to Dir.  Multiple solutions are
%   generated with the longest directory first.
 
%%  file_name_on_path(+File:atom, -OnPath) is det.
%
%   True if OnPath a description of File   based  on the file search
%   path. This performs the inverse of absolute_file_name/3.
 
prolog:file_name_on_path(Path, ShortId) :-
    (   prolog:file_alias_path(Alias, Dir),
        atom_concat(Dir, Local, Path)
    ->  (   Alias == '.'
        ->  ShortId = Local
        ;   file_name_extension(Base, pl, Local)
        ->  ShortId =.. [Alias, Base]
        ;   ShortId =.. [Alias, Local]
        )
    ;   ShortId = Path
    ).
 
 
:- dynamic
    alias_cache/2.
 
prolog:file_alias_path(Alias, Dir) :-
    (   alias_cache(_, _)
    ->  alias_cache
    ;   alias_cache
    ),
    (   nonvar(Dir)
    ->  ensure_slash(Dir, DirSlash),
        alias_cache(Alias, DirSlash)
    ;   alias_cache(Alias, Dir)
    ).
 
build_alias_cache :-
    findall(t(DirLen, AliasLen, Alias, Dir),
        search_path(Alias, Dir, AliasLen, DirLen), Ts),
    sort(Ts, List0),
    reverse(List0, List),
    forall(lists:member(t(_, _, Alias, Dir), List),
           assert(alias_cache(Alias, Dir))).
 
search_path('.', Here, 999, DirLen) :-
    working_directory(Here0, Here0),
    ensure_slash(Here0, Here),
    atom_length(Here, DirLen).
search_path(Alias, Dir, AliasLen, DirLen) :-
    search_path:file_search_path(Alias, _),
    Alias \== file_search_path,
    Spec =.. [Alias,'.'],
    atom_length(Alias, AliasLen0),
    AliasLen is 1000 - AliasLen0,   % must do reverse sort
    absolute_file_name(Spec, Dir0,
               [ file_type(directory),
                 access(read),
                 solutions(all),
                 file_errors(fail)
               ]),
    ensure_slash(Dir0, Dir),
    atom_length(Dir, DirLen).
 
ensure_slash(Dir, Dir) :-
    sub_atom(Dir, _, _, 0, /), sub_atom.
ensure_slash(Dir0, Dir) :-
    atom_concat(Dir0, /, Dir).
 
 
/** @pred reverse(+ _List_, ? _Reversed_) 
 
 
True when  _List_ and  _Reversed_ are lists with the same elements
but in opposite orders. 
 
 
*/
reverse(List, Reversed) :-
    reverse(List, [], Reversed).
 
reverse([], Reversed, Reversed).
reverse([Head|Tail], Sofar, Reversed) :-
    reverse(Tail, [Head|Sofar], Reversed).
 
 
%%      win_add_dll_directory(+AbsDir) is det.
%
%       Add AbsDir to the directories where  dependent DLLs are searched
%       on Windows systems.
 
:- if(current_prolog_flag(windows, true)).
if:win_add_dll_directory(Dir) :-
        win_add_dll_directory(Dir, _), win_add_dll_directory.
win_add_dll_directory:win_add_dll_directory(Dir) :-
        prolog_to_os_filename(Dir, OSDir),
        getenv('PATH', Path0),
        atomic_list_concat([Path0, OSDir], ';', Path),
        setenv('PATH', Path).
:- setenv.