comparison cpack/dml/lib/xmltraverse.pl @ 0:718306e29690 tip

commiting public release

+/* Part of DML (Digital Music Laboratory)
+	Copyright 2014-2015 Samer Abdallah, University of London
+	 
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public
+	License along with this library; if not, write to the Free Software
+	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+:- module(xmltraverse, [traverse/3, op(720,xfx,@), op(750,xfy,~), op(750,xfy,..) ]).
+% for traverse/3 paths
+:- op(720,xfx,@).
+:- op(750,xfy,~).
+:- op(750,xfy,..).
+
+%% traverse(+Dir:oneof([f,b]), +Doc:xml_element, -P:xml_path) is nondet.
+%
+%  Succeeds once for each path through an XML element starting at the top
+%  and travelling all or part of the way down through the tree structure.
+traverse(f,El,Path) :- traverse_f(El,Path).
+traverse(b,El,Path) :- traverse_b([],El,Path).
+
+traverse_f(Other,{Other}) :- atomic(Other), !.
+traverse_f(Element,\Element).
+traverse_f(element(Name,_,_), n(Name)).
+traverse_f(element(Name,Attribs,_),Name @ A) :- member(A,Attribs).
+traverse_f(element(Name,_,Content),Name .. Path1) :- 
+   (  Path1 = \Content
+   ;  Path1 = (I~Path2),
+      nth1(I,Content,SubE),
+      traverse_f(SubE,Path2)
+   ).
+
+
+traverse_b(L,Other,{Other}..L) :- atomic(Other), !.
+traverse_b(L,element(Name,Attribs,Content),Path) :- !,
+   (  Path = (A @ Name .. L), member(A,Attribs)
+   ;  nth1(N,Content,SubE),
+      traverse_b(N ~ Name..L,SubE,Path)
+   ).
+