* Applied patch from Melanie, mantis issue #1581 - "Refactor LSL language, api and compiler out of XEngine"

"First stage in a major Script Engine refactor, that will result in the LSL implementaions ebing reconverged. Not there yet, but one major part is done."
Thank you, Melanie!

1 files changed, 234 insertions, 0 deletions

diff --git a/OpenSim/Region/ScriptEngine/Shared/Api/Runtime/YieldProlog/BagofAnswers.cs b/OpenSim/Region/ScriptEngine/Shared/Api/Runtime/YieldProlog/BagofAnswers.cs
new file mode 100644
index 0000000..70c1b5a
--- /dev/null
+++ b/OpenSim/Region/ScriptEngine/Shared/Api/Runtime/YieldProlog/BagofAnswers.cs
@@ -0,0 +1,234 @@
+/*
+ * Copyright (C) 2007-2008, Jeff Thompson
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the copyright holder nor the names of its contributors
+ *       may be used to endorse or promote products derived from this software
+ *       without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace OpenSim.Region.ScriptEngine.Shared.YieldProlog
+{
+    /// <summary>
+    /// A BagofAnswers holds answers for bagof and setof.
+    /// </summary>
+    public class BagofAnswers
+    {
+        private object _template;
+        private Variable[] _freeVariables;
+        private Dictionary<object[], List<object>> _bagForFreeVariables;
+        private List<object> _findallBagArray;
+        private static TermArrayEqualityComparer _termArrayEqualityComparer =
+            new TermArrayEqualityComparer();
+
+        /// <summary>
+        /// To get the free variables, split off any existential qualifiers from Goal such as the X in
+        /// "X ^ f(Y)", get the set of unbound variables in Goal that are not qualifiers, then remove
+        /// the unbound variables that are qualifiers as well as the unbound variables in Template.
+        /// </summary>
+        /// <param name="Template"></param>
+        /// <param name="Goal"></param>
+        public BagofAnswers(object Template, object Goal)
+        {
+            _template = Template;
+
+            // First get the set of variables that are not free variables.
+            List<Variable> variableSet = new List<Variable>();
+            YP.addUniqueVariables(Template, variableSet);
+            object UnqualifiedGoal = YP.getValue(Goal);
+            while (UnqualifiedGoal is Functor2 && ((Functor2)UnqualifiedGoal)._name == Atom.HAT)
+            {
+                YP.addUniqueVariables(((Functor2)UnqualifiedGoal)._arg1, variableSet);
+                UnqualifiedGoal = YP.getValue(((Functor2)UnqualifiedGoal)._arg2);
+            }
+
+            // Remember how many non-free variables there are so we can find the unique free variables
+            //   that are added.
+            int nNonFreeVariables = variableSet.Count;
+            YP.addUniqueVariables(UnqualifiedGoal, variableSet);
+            int nFreeVariables = variableSet.Count - nNonFreeVariables;
+            if (nFreeVariables == 0)
+            {
+                // There were no free variables added, so we won't waste time with _bagForFreeVariables.
+                _freeVariables = null;
+                _findallBagArray = new List<object>();
+            }
+            else
+            {
+                // Copy the free variables.
+                _freeVariables = new Variable[nFreeVariables];
+                for (int i = 0; i < nFreeVariables; ++i)
+                    _freeVariables[i] = variableSet[i + nNonFreeVariables];
+
+                _bagForFreeVariables = new Dictionary<object[], List<object>>(_termArrayEqualityComparer);
+            }
+        }
+
+        public void add()
+        {
+            if (_freeVariables == null)
+                // The goal has bound the values in _template but we don't bother with _freeVariables.
+                _findallBagArray.Add(YP.makeCopy(_template, new Variable.CopyStore()));
+            else
+            {
+                // The goal has bound the values in _template and _freeVariables.
+                // Find the entry for this set of _freeVariables values.
+                object[] freeVariableValues = new object[_freeVariables.Length];
+                for (int i = 0; i < _freeVariables.Length; ++i)
+                    freeVariableValues[i] = YP.getValue(_freeVariables[i]);
+                List<object> bagArray;
+                if (!_bagForFreeVariables.TryGetValue(freeVariableValues, out bagArray))
+                {
+                    bagArray = new List<object>();
+                    _bagForFreeVariables[freeVariableValues] = bagArray;
+                }
+
+                // Now copy the template and add to the bag for the freeVariables values.
+                bagArray.Add(YP.makeCopy(_template, new Variable.CopyStore()));
+            }
+        }
+
+        /// <summary>
+        /// For each result, unify the _freeVariables and unify bagArrayVariable with the associated bag.
+        /// </summary>
+        /// <param name="bagArrayVariable">this is unified with the List<object> of matches for template that
+        /// corresponds to the bindings for freeVariables.  Be very careful: this does not unify with a Prolog
+        /// list.</param>
+        /// <returns></returns>
+        public IEnumerable<bool> resultArray(Variable bagArrayVariable)
+        {
+            if (_freeVariables == null)
+            {
+                // No unbound free variables, so we only filled one bag.  If empty, bagof fails.
+                if (_findallBagArray.Count > 0)
+                {
+                    foreach (bool l1 in bagArrayVariable.unify(_findallBagArray))
+                        yield return false;
+                }
+            }
+            else
+            {
+                foreach (KeyValuePair<object[], List<object>> valuesAndBag in _bagForFreeVariables)
+                {
+                    foreach (bool l1 in YP.unifyArrays(_freeVariables, valuesAndBag.Key))
+                    {
+                        foreach (bool l2 in bagArrayVariable.unify(valuesAndBag.Value))
+                            yield return false;
+                    }
+                    // Debug: Should we free memory of the answers already returned?
+                }
+            }
+        }
+
+        /// <summary>
+        /// For each result, unify the _freeVariables and unify Bag with the associated bag.
+        /// </summary>
+        /// <param name="Bag"></param>
+        /// <returns></returns>
+        public IEnumerable<bool> result(object Bag)
+        {
+            Variable bagArrayVariable = new Variable();
+            foreach (bool l1 in resultArray(bagArrayVariable))
+            {
+                foreach (bool l2 in YP.unify(Bag, ListPair.make((List<object>)bagArrayVariable.getValue())))
+                    yield return false;
+            }
+        }
+
+        /// <summary>
+        /// For each result, unify the _freeVariables and unify Bag with the associated bag which is sorted
+        /// with duplicates removed, as in setof.
+        /// </summary>
+        /// <param name="Bag"></param>
+        /// <returns></returns>
+        public IEnumerable<bool> resultSet(object Bag)
+        {
+            Variable bagArrayVariable = new Variable();
+            foreach (bool l1 in resultArray(bagArrayVariable))
+            {
+                List<object> bagArray = (List<object>)bagArrayVariable.getValue();
+                YP.sortArray(bagArray);
+                foreach (bool l2 in YP.unify(Bag, ListPair.makeWithoutRepeatedTerms(bagArray)))
+                    yield return false;
+            }
+        }
+
+        public static IEnumerable<bool> bagofArray
+            (object Template, object Goal, IEnumerable<bool> goalIterator, Variable bagArrayVariable)
+        {
+            BagofAnswers bagOfAnswers = new BagofAnswers(Template, Goal);
+            foreach (bool l1 in goalIterator)
+                bagOfAnswers.add();
+            return bagOfAnswers.resultArray(bagArrayVariable);
+        }
+
+        public static IEnumerable<bool> bagof
+            (object Template, object Goal, IEnumerable<bool> goalIterator, object Bag)
+        {
+            BagofAnswers bagOfAnswers = new BagofAnswers(Template, Goal);
+            foreach (bool l1 in goalIterator)
+                bagOfAnswers.add();
+            return bagOfAnswers.result(Bag);
+        }
+
+        public static IEnumerable<bool> setof
+            (object Template, object Goal, IEnumerable<bool> goalIterator, object Bag)
+        {
+            BagofAnswers bagOfAnswers = new BagofAnswers(Template, Goal);
+            foreach (bool l1 in goalIterator)
+                bagOfAnswers.add();
+            return bagOfAnswers.resultSet(Bag);
+        }
+
+        /// <summary>
+        /// A TermArrayEqualityComparer implements IEqualityComparer to compare two object arrays using YP.termEqual.
+        /// </summary>
+        private class TermArrayEqualityComparer : IEqualityComparer<object[]>
+        {
+            public bool Equals(object[] array1, object[] array2)
+            {
+                if (array1.Length != array2.Length)
+                    return false;
+                for (int i = 0; i < array1.Length; ++i)
+                {
+                    if (!YP.termEqual(array1[i], array2[i]))
+                        return false;
+                }
+                return true;
+            }
+
+            public int GetHashCode(object[] array)
+            {
+                int hashCode = 0;
+                for (int i = 0; i < array.Length; ++i)
+                    hashCode ^= array[i].GetHashCode();
+                return hashCode;
+            }
+        }
+    }
+}