Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System.Data.SqlXml/System/Xml/Xsl/XPath/IXPathEnvironment.cs

@@ -0,0 +1,33 @@
+//------------------------------------------------------------------------------
+// <copyright file="IXPathEnvironment.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>                                                                
+// <owner current="true" primary="true">[....]</owner>
+//------------------------------------------------------------------------------
+using System.Collections.Generic;
+using System.Xml.Xsl.Qil;
+
+namespace System.Xml.Xsl.XPath {
+
+    // <spec>http://www.w3.org/TR/xslt20/#dt-focus</spec>
+    internal interface IFocus {
+        // The context item:     the item currently being processed
+        QilNode GetCurrent();
+
+        // The context position: the position of the context item within the sequence of items
+        // currently being processed
+        QilNode GetPosition();
+
+        // The context size:     the number of items in the sequence of items currently being processed
+        QilNode GetLast();
+    }
+
+    internal interface IXPathEnvironment : IFocus {
+        XPathQilFactory Factory { get; }
+
+        // Resolution of variables, functions, and prefixes
+        QilNode ResolveVariable(string prefix, string name);
+        QilNode ResolveFunction(string prefix, string name, IList<QilNode> args, IFocus env);
+        string  ResolvePrefix  (string prefix);
+    }
+}