1/*  Part of XPCE --- The SWI-Prolog GUI toolkit
    2
    3    Author:        Jan Wielemaker and Anjo Anjewierden
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org/packages/xpce/
    6    Copyright (c)  1999-2011, University of Amsterdam
    7                              VU University Amsterdam
    8    All rights reserved.
    9
   10    Redistribution and use in source and binary forms, with or without
   11    modification, are permitted provided that the following conditions
   12    are met:
   13
   14    1. Redistributions of source code must retain the above copyright
   15       notice, this list of conditions and the following disclaimer.
   16
   17    2. Redistributions in binary form must reproduce the above copyright
   18       notice, this list of conditions and the following disclaimer in
   19       the documentation and/or other materials provided with the
   20       distribution.
   21
   22    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   23    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   24    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   25    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   26    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   27    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   28    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   29    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   30    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   32    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   33    POSSIBILITY OF SUCH DAMAGE.
   34*/
   35
   36:- module(pce_meta,
   37          [ pce_to_method/2,            % +Spec, -BehaviourObject
   38            isa_class/2,                % ?SubClassName, ?SuperClassName
   39            current_class/2,            % ?ClassName, ?ClassObject
   40            to_class_name/2,            % +NameOrClass, -ClassName
   41            pce_library_class/4,        % ?Name, ?Super, ?Comment, ?File
   42            implements/2,               % ?Class, ?SendOrGet(?Name)
   43            implements/3,               % idem, -Method
   44            pce_to_pl_type/2,           % +PceType, -PrologType
   45            type_accepts_function/1,    % +Type
   46            classify_class/2            % +Class, -Classification
   47          ]).   48:- use_module(library(pce)).   49:- require([ pce_error/1
   50           , chain_list/2
   51           , get_chain/3
   52           , maplist/3
   53           ]).   54
   55/** <module> Reflection support for XPCE
   56
   57This module defines utilities to  simplify   reflexion  support of XPCE,
   58notably implementing non-deterministic logical relations   on top of the
   59deterministic XPCE methods.
   60*/
   61
   62
   63                 /*******************************
   64                 *      INTERACTION SUPPORT     *
   65                 *******************************/
   66
   67%!  pce_to_method(+Spec, -Object) is semidet.
   68%
   69%   Object is the XPCE object described by Spec.  Spec is one of
   70%
   71%           * send(Receiver, Selector)
   72%           * ->(Receiver, Selector)
   73%           Find a send-method on Receiver
   74%           * get(Receiver, Selector)
   75%           * <-(Receiver, Selector)
   76%           Find a get-method on Receiver
   77%           * Receiver-Selector
   78%           Find an instance variable (slot) on Receiver
   79%           * ClassName
   80%           Find a class from its name
   81
   82pce_to_method(->(Receiver, Selector), Method) :-
   83    !,
   84    (   atom(Receiver)
   85    ->  get(@pce, convert, Receiver, class, Class),
   86        get(Class, send_method, Selector, Method)
   87    ;   object(Receiver)
   88    ->  get(Receiver, send_method, Selector, tuple(_, Method))
   89    ).
   90pce_to_method(<-(Receiver, Selector), Method) :-
   91    !,
   92    (   atom(Receiver)
   93    ->  get(@pce, convert, Receiver, class, Class),
   94        get(Class, get_method, Selector, Method)
   95    ;   object(Receiver)
   96    ->  get(Receiver, get_method, Selector, tuple(_, Method))
   97    ).
   98pce_to_method((Receiver-Selector), Method) :-
   99    !,
  100    (   atom(Receiver)
  101    ->  get(@pce, convert, Receiver, class, Class),
  102        get(Class, instance_variable, Selector, Method)
  103    ;   object(Receiver),
  104        get(Receiver, attribute, Method)
  105    ->  true
  106    ;   object(Receiver),
  107        get(Receiver, class, Class),
  108        get(Class, instance_variable, Selector, Method)
  109    ).
  110pce_to_method(ClassName, Class) :-
  111    atom(ClassName),
  112    get(@pce, convert, ClassName, class, Class),
  113    !.
  114pce_to_method(Method, Method) :-
  115    object(Method),
  116    !.
  117pce_to_method(get(Receiver, Selector), Method) :-
  118    !,
  119    pce_to_method(<-(Receiver, Selector), Method).
  120pce_to_method(send(Receiver, Selector), Method) :-
  121    !,
  122    pce_to_method(->(Receiver, Selector), Method).
  123
  124
  125                 /*******************************
  126                 *           CLASSES            *
  127                 *******************************/
  128
  129%!  isa_class(?Sub, ?Super)
  130%
  131%   Succeeds if Sub is Super or below Super.  Can be used with any
  132%   instantiation.  If class is instantiated the super-chain is
  133%   followed.
  134
  135isa_class(Class, Super) :-
  136    ground(Class),
  137    !,
  138    gen_super(Class, Super).
  139isa_class(Class, Super) :-
  140    current_class(Class, ClassObject),
  141    current_class(Super, SuperObject),
  142    send(ClassObject, is_a, SuperObject).
  143
  144gen_super(Class, Class).
  145gen_super(Class, Super) :-
  146    current_class(Class, ClassObject),
  147    get(ClassObject, super_class, SuperObject),
  148    current_class(Super0, SuperObject),
  149    gen_super(Super0, Super).
  150
  151
  152%!  current_class(?Name, ?Class)
  153%
  154%   Convert between name and class object.  Insufficient instantation
  155%   enumerates the classes.
  156
  157:- dynamic
  158    current_class_cache/2.  159
  160
  161make_current_class :-
  162    retractall(current_class_cache(_,_)),
  163    send(@classes, for_all,
  164         message(@prolog, assert_class, @arg1, @arg2)),
  165    send(class(class), created_message,
  166         message(@prolog, assert_class, @arg2?name, @arg2)).
  167
  168assert_class(Name, Object) :-
  169    assert(current_class_cache(Name, Object)).
  170
  171:- initialization
  172    make_current_class.  173
  174current_class(Class, ClassObject) :-
  175    current_class_cache(Class, ClassObject).
  176current_class(Class, ClassObject) :-
  177    pce_prolog_class(Class),
  178    \+ current_class_cache(Class, _),
  179    get(@pce, convert, Class, class, ClassObject).
  180
  181
  182%!  to_class_name(+AtomOrClass, -ClassName)
  183%
  184%   Convert a name or class-object into a class name
  185
  186to_class_name(Name0, Name) :-
  187    atom(Name0),
  188    !,
  189    (   current_class(Name0, _)
  190    ->  Name = Name0
  191    ;   pce_error(no_class(Name0))
  192    ).
  193to_class_name(ClassObj, Name) :-
  194    object(ClassObj),
  195    send(ClassObj, instance_of, class),
  196    !,
  197    get(ClassObj, name, Name).
  198
  199
  200                 /*******************************
  201                 *            LIBRARY           *
  202                 *******************************/
  203
  204:- dynamic
  205    library_index/4,
  206    index_files/1.  207
  208%!  pce_library_class(?Name, ?Super, ?Comment, ?File)
  209%
  210%   Examine the library index for defined classes.
  211
  212pce_library_class(Name, Super, Comment, library(File)) :-
  213    atom(Name),
  214    !,
  215    (   library_index(Name, Super, Comment, File)
  216    *-> true
  217    ;   update_library_index,
  218        library_index(Name, Super, Comment, File)
  219    ).
  220
  221update_library_index :-
  222    setof(File, index_file(File), Files),
  223    (   index_files(Files)
  224    ->  true
  225    ;   retractall(index_files(_)),
  226        retractall(library_index(_,_,_,_)),
  227        load_index_files(Files),
  228        assert(index_files(Files))
  229    ).
  230
  231
  232index_file(File) :-
  233    absolute_file_name(library('CLASSINDEX.pl'), File,
  234                       [ access(read),
  235                         solutions(all),
  236                         file_errors(fail)
  237                       ]).
  238
  239load_index_files([]).
  240load_index_files([H|T]) :-
  241    load_index_file(H),
  242    load_index_files(T).
  243
  244load_index_file(File) :-
  245    open(File, read, In),
  246    read(In, Term),
  247    call_cleanup(read_index(Term, In), close(In)).
  248
  249read_index(end_of_file, _) :- !.
  250read_index(class(Name, Super, Comment, File), In) :-
  251    assert(library_index(Name, Super, Comment, File)),
  252    read(In, Term),
  253    read_index(Term, In).
  254
  255
  256                 /*******************************
  257                 *            METHODS           *
  258                 *******************************/
  259
  260%!  implements(?Class:atom, ?Method:atom) is nondet.
  261%!  implements(?Class:atom, ?Method:atom, -MethodObj:object) is nondet.
  262%
  263%   True if Class implements the method.  If class is a variable,
  264%   backtracking yields all classes
  265%
  266%   `What'  may  be  wrapped  in  self(What)  or  root(What).  Using
  267%   self(What) returns only those classes  that have a non-inherited
  268%   implementation of the method,  while   using  root(What) returns
  269%   only  those  classes  for   which    there   is  no  super-class
  270%   implementing the requested method.
  271%
  272%   @param Class    Name of XPCE class
  273%   @param Method   One of send(Name) or get(Name)
  274%   @param MethodObj XPCE Object representing the method
  275
  276implements(Class, What) :-
  277    implements(Class, What, _).
  278
  279implements(Class, self(What), Method) :-
  280    implements(Class, What, Method),
  281    get(Method, context, ClassObject),
  282    get(ClassObject, name, Class).
  283implements(Class, root(What), Method) :-
  284    implements(Class, self(What), Method),
  285    (   send(Method, has_get_method, inherited_from)
  286    ->  \+ get(Method, inherited_from, _)
  287    ;   true
  288    ).
  289implements(Class, send(Name), Method) :-
  290    current_class(Class, ClassObject),
  291    (   atom(Name)
  292    ->  get(ClassObject, send_method, Name, Method)
  293    ;   isa_class(Class, Super),
  294        current_class(Super, SuperObject),
  295        (   get_chain(SuperObject, send_methods, Methods)
  296        ;   get_chain(SuperObject, instance_variables, Methods)
  297        ),
  298        member(Method, Methods),
  299        get(Method, name, Name),
  300        get(ClassObject, send_method, Name, Method)         % not overruled
  301    ).
  302implements(Class, get(Name), Method) :-
  303    current_class(Class, ClassObject),
  304    (   atom(Name)
  305    ->  get(ClassObject, get_method, Name, Method)
  306    ;   isa_class(Class, Super),
  307        current_class(Super, SuperObject),
  308        (   get_chain(SuperObject, get_methods, Methods)
  309        ;   get_chain(SuperObject, instance_variables, Methods)
  310        ),
  311        member(Method, Methods),
  312        get(Method, name, Name),
  313        get(ClassObject, get_method, Name, Method)
  314    ).
  315
  316
  317                 /*******************************
  318                 *             TYPES            *
  319                 *******************************/
  320
  321%!  pce_to_pl_type(+PceType, -PrologType)
  322%   Convert an XPCE Type object to our type-checkers type-logic.
  323%
  324
  325pce_to_pl_type(Type, Pl) :-
  326    get(Type, kind, Kind),
  327    pce_to_pl_type(Kind, Type, Pl0),
  328    type_supers(Pl0, Type, Pl).
  329
  330type_supers(Pl0, Type, Pl) :-
  331    get(Type, supers, Supers),
  332    Supers \== @nil,
  333    !,
  334    chain_list(Supers, SuperList),
  335    maplist(pce_to_pl_type, SuperList, PlSupers),
  336    list_to_or([Pl0|PlSupers], Pl).
  337type_supers(Pl, _, Pl).
  338
  339pce_to_pl_type(class, Type, Pl) :-
  340    get(Type, context, Context),
  341    (   atom(Context)
  342    ->  Class = Context
  343    ;   get(Context, name, Class)
  344    ),
  345    class_type(Class, Pl).
  346pce_to_pl_type(class_object, _, and(sub(object), not(sub(function)))).
  347pce_to_pl_type(unchecked,    _, or(sub(object), integer)).
  348pce_to_pl_type(any,          _, and(or(sub(object), integer),
  349                                    not(sub(function)))).
  350pce_to_pl_type(int,          _, integer).
  351pce_to_pl_type(char,         _, integer(0,255)).
  352pce_to_pl_type(int_range,    T, integer(Low, High)) :-
  353    get(T, context, tuple(Low0, High0)),
  354    to_range_boundary(Low0, Low),
  355    to_range_boundary(High0, High).
  356pce_to_pl_type(real_range,   T, float(Low, High)) :-
  357    get(T, context, tuple(Low0, High0)),
  358    to_range_boundary(Low0, Low),
  359    to_range_boundary(High0, High).
  360pce_to_pl_type(event_id,     _, or(integer, atom)).
  361pce_to_pl_type(value,        T, value(V)) :-
  362    get(T, context, V).
  363pce_to_pl_type(name_of,      T, Pl) :-
  364    get_chain(T, context, Atoms),
  365    list_to_value_or(Atoms, Pl).
  366pce_to_pl_type(member,       T, PlType) :-
  367    get(T, context, T2),
  368    pce_to_pl_type(T2, PlType).
  369pce_to_pl_type(value_set,    T, Pl) :-
  370    get_chain(T, context, Elements),
  371    list_to_value_or(Elements, Pl).
  372pce_to_pl_type(compound,     T, PlType) :-
  373    get_chain(T, context, Supers),
  374    maplist(pce_to_pl_type, Supers, PlSupers),
  375    list_to_or(PlSupers, PlType).
  376pce_to_pl_type(alias,        T, PlType) :-
  377    get(T, context, T2),
  378    pce_to_pl_type(T2, PlType).
  379pce_to_pl_type(alien,        _, integer).
  380
  381class_type(name,   atom) :- !.
  382class_type(number, integer) :- !.
  383class_type(real,   float) :- !.
  384class_type(Class,  sub(Class)).
  385
  386to_range_boundary(N, unbound) :-
  387    unbound(N),
  388    !.
  389to_range_boundary(N, N).
  390
  391unbound(@nil).
  392unbound(1073741823).
  393unbound(-1073741824).
  394
  395
  396list_to_or([X], X) :- !.
  397list_to_or([A|B], or(A, C)) :-
  398    list_to_or(B, C).
  399
  400list_to_value_or([X], value(X)) :- !.
  401list_to_value_or([A|B], or(value(A), T)) :-
  402    list_to_value_or(B, T).
  403
  404%!  type_accepts_function(+Type)
  405%
  406%   Succeeds if Type accepts function arguments
  407
  408type_accepts_function(Type) :-
  409    send(type(function), specialised, Type).
  410
  411%!  classify_class(+ClassName, -Classification) is det.
  412%
  413%   Classify an XPCE class.  Defined classes are:
  414%
  415%     * built_in
  416%     * file(File)
  417%     * library(File)
  418%     * user(File)
  419%     * user
  420%     * undefined
  421
  422classify_class(Name, built_in) :-
  423    get(@classes, member, Name, Class),
  424    get(Class, creator, built_in),
  425    !.
  426classify_class(Name, library(File)) :-
  427    pce_library_class(Name, _, _, FileSpec),
  428    FileSpec = library(File),
  429    (   get(@classes, member, Name, Class),
  430        get(Class, source, source_location(File, _Line))
  431    ->  absolute_file_name(FileSpec, File,
  432                           [ access(read)
  433                           ])
  434
  435    ;   true
  436    ),
  437    !.
  438classify_class(Name, user(File)) :-
  439    get(@classes, member, Name, Class),
  440    get(Class, source, source_location(File, _Line)).
  441classify_class(Name, user(File)) :-
  442    pce_prolog_class(Name),
  443    pce_principal:pce_class(Name, _Meta, _Super, _Vars, _Res, Attributes),
  444    memberchk(send(@class, source, source_location(File, _Line)),
  445              Attributes),
  446    !.
  447classify_class(Name, user) :-
  448    get(@classes, member, Name, _),
  449    !.
  450classify_class(_, undefined)