:- module(xml_info,
[beautify_prolog_xml/2,
test_access_functions/0]
).
:- ensure_loaded('$REGULUS/PrologLib/compatibility').
'SICSTUS3/4'( ( :- use_module(library(charsio)) ), ( :- use_module('$REGULUS/PrologLib/compatibility_charsio') ) ).
:- use_module(library(lists)).
:- use_module(library(xml)).
:- use_module('$REGULUS/PrologLib/utilities').
%Predicates to make the search result XML look ok
beautify_prolog_xml(XML1, XML4):-
change_pcdata_into_atoms(XML1, XML2),
change_strings_into_atoms(XML2, XML3),
beautify_prolog_xml1(XML3, XML4).
beautify_prolog_xml1([F|Rest], [F1|Rest1]) :-
beautify_prolog_xml1(F, F1),
beautify_prolog_xml1(Rest,Rest1).
beautify_prolog_xml1(Stuff, Stuff).
%============================================================
change_pcdata_into_atoms(pcdata(String), Output) :-
atom_codes(Atom, String),
( atom_to_int(Atom, Number) ->
Output = Number ;
Output = Atom
),
!.
change_pcdata_into_atoms(Atom, Atom) :-
( atomic(Atom) ; var(Atom) ),
!.
change_pcdata_into_atoms(T, T1) :-
functor(T, F, N),
functor(T1, F, N),
change_pcdata_into_atoms_args(N, T, T1),
!.
change_pcdata_into_atoms_args(0, _T, _T1).
change_pcdata_into_atoms_args(I, T, T1) :-
I > 0,
arg(I, T, Arg),
arg(I, T1, Arg1),
change_pcdata_into_atoms(Arg, Arg1),
I1 is I - 1,
!,
change_pcdata_into_atoms_args(I1, T, T1).
%============================================================
change_strings_into_atoms(X=String, X=Output) :-
atom_codes(Atom, String),
( atom_to_int(Atom, Number) ->
Output = Number ;
Output = Atom
),
!.
change_strings_into_atoms(Atom, Atom) :-
( atomic(Atom) ; var(Atom) ),
!.
change_strings_into_atoms(T, T1) :-
functor(T, F, N),
functor(T1, F, N),
change_strings_into_atoms_args(N, T, T1),
!.
change_strings_into_atoms_args(0, _T, _T1).
change_strings_into_atoms_args(I, T, T1) :-
I > 0,
arg(I, T, Arg),
arg(I, T1, Arg1),
change_strings_into_atoms(Arg, Arg1),
I1 is I - 1,
!,
change_strings_into_atoms_args(I1, T, T1).
%============================================================
/*
Work down the XML until you get to the list of items under
"post". Then get the values.
*/
/*
extract_xml_info(XML, InfoType, Value):-
get_xml_content(XML, Content),
get_message(Content, Message),
get_result(Message, Result),
get_task_posts(Result, TaskPosts),
get_attribute_value(InfoType, TaskPosts, Value).
%the top level has predicate xml/2
get_xml_content(XML, Content):-
XML = xml(_VersionEncoding, Content).
%most other levels have element items which have 3 arguments
get_message(XML_SubTerm, Message):-
XML_SubTerm = [element(message, _, Message)].
get_result(XML_SubTerm, Result):-
XML_SubTerm = [element(result, _, Result)].
% Since there are three kinds of "posts" under results, we take only the TaskPosts
% which are the only ones filled in the example. If you wanted Event or Note
% you could do something very similar
get_task_posts(XML_SubTerm, TaskPosts):-
XML_SubTerm = [element(posts, [category='Task'|_], TaskPosts),_Event, _Note].
%There are 9 items in the post, here are matches for 7 of them.
get_attribute_value(id, [element(post,_,[element('id',_,[ID]),_,_,_,_,_,_,_,_,_])], ID).
get_attribute_value(createtime, [element(post,_,[_,element('createtime',_,[CreateTime]),_,_,_,_,_,_,_,_])], CreateTime).
get_attribute_value(createtime_epoch, [element(post,_,[_,_,element('createtime_epoch',_,[CreateTimeEpoch]),_,_,_,_,_,_,_])], CreateTimeEpoch).
get_attribute_value(media_type, [element(post,_,[_,_,_,element('media_type',_,[MediaType]),_,_,_,_,_,_])], MediaType).
get_attribute_value(transcriptstatus, [element(post,_,[_,_,_,_,element('transcriptstatus',_,[TranscriptStatus]),_,_,_,_,_])], TranscriptStatus).
get_attribute_value(transcript, [element(post,_,[_,_,_,_,_,element('transcript',_,[Transcript]),_,_,_,_])], Transcript).
get_attribute_value(duration, [element(post,_,[_,_,_,_,_,_,element('duration',_,[Duration]),_,_,_])], Duration).
*/
%============================================================
test_access_functions :-
prolog_xml(test2, XML), %use the test xml
format('~N~w~n~n', [XML]), %print it out
%InfoType = media_type,
InfoType = createtime,
extract_xml_info(XML, InfoType, Value),
format('~NThe value of ~q is:~n~q~n', [InfoType, Value]).
%prologized xml for testing
prolog_xml(test2,
xml([version='1.0',encoding='UTF-8'],
[element(message, [],
[element(result, [type=success],
[element(posts, [category='Task',howmany=1],
[element(post, [],
[element(id,[],[149667]),
element(createtime,[],['2008-05-21 20:07']),
element(createtime_epoch,[],[1211400471]),
element(media_type,[],['Text']),
element(transcriptstatus,[],['DONE']),
element(transcript, [],
['This is a sample post from Sunil']),
element(duration,[],[0]),
element(property, [set=yes],
[element(name,[],[status]),
element(value,[],['PENDING']),
element(last_updated_at, [],
['2008-05-21 20:07']),
element(updated_at_epoch,[],[1211400471])]),
element(calendardate,[set=no],[]),
element(delegation,[delegated=false],[])])]),
element(posts,[category='Event',howmany=0],[]),
element(posts,[category='Note',howmany=0],[])])])])).
/* A more general way to get information from the xml
but it's more difficult to understand
*/
extract_xml_info_generic(PrologisedXML, InfoType, Values) :-
extract_xml_info1(PrologisedXML, InfoType, Values-[]). %calling a predicate that uses difference lists
% if you are looking at the right level just get the value
extract_xml_info1(element(InfoType, _Feats, [Value]), InfoType, [Value | Rest]-Rest) :-
!.
% if you are looking at an atom, you aren't going to find a value
extract_xml_info1(Atom, _InfoType, Values-Values) :-
atomic(Atom),
!.
% if you are looking at a variable, you aren't going to find a value
extract_xml_info1(Var, _InfoType, Values-Values) :-
var(Var),
!.
%if it's a compound term figure out how many args there are and work through them
extract_xml_info1(Term, InfoType, ValuesIn-ValuesOut) :-
compound(Term),
functor(Term, _F, N), %figure out the number of arguments
extract_xml_info_args(N, Term, InfoType, ValuesIn-ValuesOut). %use the number of args to know when you're done
%this predicate counts through the arguments of a predicate counting down until you're done
%no arguments left
extract_xml_info_args(I, _Term, _InfoType, Values-Values) :-
I < 1,
!.
%still have args to process
extract_xml_info_args(I, Term, InfoType, ValuesIn-ValuesOut) :-
I >= 1, %1 or more args
arg(I, Term, Arg), %get the Ith arg
extract_xml_info1(Arg, InfoType, ValuesIn-ValuesNext), %look for the value in the Ith arg
I1 is I - 1, %decrement
!,
extract_xml_info_args(I1, Term, InfoType, ValuesNext-ValuesOut). %do it for the rest of the list