creating and selecting via LINQ works now

mocha-dotnet/src/lib/Mocha.Core/Modeling/OmsDatabase.cs

@@ -243,4 +243,28 @@ public class OmsDatabase
 			}
 		}
     }
+
+	private Dictionary<InstanceHandle, OmsClass> _classesByHandle = new Dictionary<InstanceHandle, OmsClass>();
+	private Dictionary<OmsClass, InstanceHandle> _handlesByClass = new Dictionary<OmsClass, InstanceHandle>();
+
+    public OmsClass GetClass(InstanceHandle handle)
+    {
+		if (_classesByHandle.ContainsKey(handle))
+		{
+			return _classesByHandle[handle];
+		}
+		return null;
+    }
+
+    internal void CreateClass(OmsClass item, Guid localClassGuid, Guid localInstanceGuid)
+    {
+		InstanceHandle ih = Oms.CreateInstanceOf(Oms.GetInstance(localClassGuid), localInstanceGuid);
+		RegisterClass(item, ih);
+    }
+
+    private void RegisterClass(OmsClass item, InstanceHandle ih)
+    {
+		_classesByHandle[ih] = item;
+		_handlesByClass[item] = ih;
+    }
 }

mocha-dotnet/src/lib/Mocha.Core/Modeling/OmsInstanceList.cs

@@ -19,15 +19,58 @@ public class OmsInstanceList<T> : OmsInstanceList, IList<T> where T : OmsClass
 	private OmsDatabase omsdb;
 	private Guid classGuid;
 
+	public class Enumerator : IEnumerator<T>
+	{
+		protected T GetCurrent()
+		{
+			InstanceHandle _Current = _listEnumerator.Current;
+			if (_Current == InstanceHandle.Empty)
+			{
+				return null;
+			}
+			return (T) omsdb.GetClass(_Current);
+		}
+
+		public T Current => GetCurrent();
+
+		object IEnumerator.Current => GetCurrent();
+
+		private IEnumerable<InstanceHandle> _list;
+		private IEnumerator<InstanceHandle> _listEnumerator;
+
+		private OmsDatabase omsdb;
+		public Enumerator(OmsDatabase omsdb, IEnumerable<InstanceHandle> list)
+		{
+			this.omsdb = omsdb;
+			_list = list;
+			_listEnumerator = _list.GetEnumerator();
+		}
+
+		public void Dispose()
+		{
+			_listEnumerator.Dispose();
+		}
+
+		public bool MoveNext()
+		{
+			return _listEnumerator.MoveNext();
+		}
+
+		public void Reset()
+		{
+			_listEnumerator.Reset();
+		}
+	}
+
 	public OmsInstanceList(OmsDatabase omsdb, Guid classGuid)
 	{
 		this.omsdb = omsdb;
 		this.classGuid = classGuid;
 	}
 
-    public T this[int index] { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
+	public T this[int index] { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
 
-    public int Count
+	public int Count
 	{
 		get
 		{
@@ -36,61 +79,62 @@ public class OmsInstanceList<T> : OmsInstanceList, IList<T> where T : OmsClass
 		}
 	}
 
-    public bool IsReadOnly => throw new NotImplementedException();
+	public bool IsReadOnly => throw new NotImplementedException();
 
-    public void Add(T item)
+	public void Add(T item)
-    {
+	{
 		if (item.GlobalIdentifier == Guid.Empty)
 		{
 			Guid localClassGuid = OmsDatabase.GetGlobalIdentifierForClass(item.GetType());
 			Guid localInstanceGuid = Guid.NewGuid();
 
-			omsdb.Oms.CreateInstanceOf(omsdb.Oms.GetInstance(localClassGuid), localInstanceGuid);
+			omsdb.CreateClass(item, localClassGuid, localInstanceGuid);
 		}
-    }
+	}
 
-    public void Clear()
+	public void Clear()
-    {
+	{
-        throw new NotImplementedException();
+		throw new NotImplementedException();
-    }
+	}
 
-    public bool Contains(T item)
+	public bool Contains(T item)
-    {
+	{
-        throw new NotImplementedException();
+		throw new NotImplementedException();
-    }
+	}
 
-    public void CopyTo(T[] array, int arrayIndex)
+	public void CopyTo(T[] array, int arrayIndex)
-    {
+	{
-        throw new NotImplementedException();
+		throw new NotImplementedException();
-    }
+	}
 
-    public IEnumerator<T> GetEnumerator()
+	public IEnumerator<T> GetEnumerator()
-    {
+	{
-        throw new NotImplementedException();
+		IReadOnlyCollection<InstanceHandle> ihs = omsdb.Oms.GetInstancesOf(omsdb.Oms.GetInstance(classGuid));
-    }
+		return new Enumerator(omsdb, ihs);
+	}
 
-    public int IndexOf(T item)
+	public int IndexOf(T item)
-    {
+	{
-        throw new NotImplementedException();
+		throw new NotImplementedException();
-    }
+	}
 
-    public void Insert(int index, T item)
+	public void Insert(int index, T item)
-    {
+	{
-        throw new NotImplementedException();
+		throw new NotImplementedException();
-    }
+	}
 
-    public bool Remove(T item)
+	public bool Remove(T item)
-    {
+	{
-        throw new NotImplementedException();
+		throw new NotImplementedException();
-    }
+	}
 
-    public void RemoveAt(int index)
+	public void RemoveAt(int index)
-    {
+	{
-        throw new NotImplementedException();
+		throw new NotImplementedException();
-    }
+	}
 
-    IEnumerator IEnumerable.GetEnumerator()
+	IEnumerator IEnumerable.GetEnumerator()
-    {
+	{
-        throw new NotImplementedException();
+		throw new NotImplementedException();
-    }
+	}
 }

mocha-dotnet/src/lib/Mocha.Core/Oms.cs

@@ -628,4 +628,10 @@ public abstract class Oms
 		//!FIXME: remove when we have sibling relationships
 		AssignRelationship(inheritsFrom, GetInstance(KnownRelationshipGuids.Class__has_sub__Class), classInstance);
     }
+
+    public IReadOnlyCollection<InstanceHandle> GetInstancesOf(InstanceHandle classInstance)
+    {
+		IReadOnlyCollection<InstanceHandle> insts = GetRelatedInstances(classInstance, GetInstance(KnownRelationshipGuids.Class__has__Instance));
+		return insts;
+    }
 }

mocha-dotnet/tests/Mocha.Core.Tests/SampleDatabases/VehicleForHireTests.cs

@@ -85,12 +85,24 @@ public class VehicleForHireTests : OmsModelingTestsBase
 	}
 
 	[Test]
-	public void RelationshipsCreated()	{
+	public void RelationshipsCreated()
+	{
 		CheckRelationshipExists(new Guid("{867126b9-294e-454f-b9c5-88df44353014}"), new Guid("{4b6f186c-babe-4c42-840b-3840373f68c2}"), "has", new Guid("{38a492b9-901f-4074-af45-642e812b51f5}"));
+	}
 
+	[Test]
+	public void CreateBusinessAndTestLinq()
+	{
 		VehicleForHireDB db = (VehicleForHireDB) GetDatabase();
 
 		VehicleForHireDB.Business busn = new VehicleForHireDB.Business("Ryde Rentals Transportation");
 		db.Businesses.Add(busn);
+
+		var query2 = from b in db.Businesses where b.Name == "test" select b;
+		Assert.That(query2.Count(), Is.EqualTo(0));
+
+		var query3 = from b in db.Businesses where b.Name == "Ryde Rentals Transportation" select b;
+		var busn3 = query3.First();
+		Assert.That(busn3.GlobalIdentifier, Is.EqualTo(busn.GlobalIdentifier));
 	}
 }