moved To... extension methods to be more consistent in where they can be found

src/Hl7.Fhir.Base/ElementModel/ISourceNode.cs

@@ -8,52 +8,51 @@
 
 using System.Collections.Generic;
 
-namespace Hl7.Fhir.ElementModel
+namespace Hl7.Fhir.ElementModel;
+
+/// <summary>
+/// A node within a tree of FHIR data.
+/// </summary>
+/// <remarks>
+/// <para>This interface is typically implemented by a parser for one of the low-level serialization formats for FHIR, i.e.
+/// FHIR xml/json/rdf or v3 XML. The interface does not depend on the availability of FHIR metadata and definitions
+/// (in contrast to <see cref="ITypedElement" />), so the names of the nodes will have their type suffixes (for choice types) 
+/// and all primitives values are represented as strings, instead of native objects.</para>
+/// <para>Implementations of this interface that want to report errors while parsing should only do so on the 
+/// <see cref="Children(string)"/> function and <see cref="Text"/> getter.</para>
+/// </remarks>
+public interface ISourceNode
 {
     /// <summary>
-    /// A node within a tree of FHIR data.
+    /// Gets the name of the node, e.g. "active", "valueQuantity".
     /// </summary>
-    /// <remarks>
-    /// <para>This interface is typically implemented by a parser for one of the low-level serialization formats for FHIR, i.e.
-    /// FHIR xml/json/rdf or v3 XML. The interface does not depend on the availability of FHIR metadata and definitions
-    /// (in contrast to <see cref="ITypedElement" />), so the names of the nodes will have their type suffixes (for choice types) 
-    /// and all primitives values are represented as strings, instead of native objects.</para>
-    /// <para>Implementations of this interface that want to report errors while parsing should only do so on the 
-    /// <see cref="Children(string)"/> function and <see cref="Text"/> getter.</para>
+    /// <remarks>Since the node has no type information, choice elements are represented as their 
+    /// name on the wire, possibly including the type suffix for choice elements.
     /// </remarks>
-    public interface ISourceNode
-    {
-        /// <summary>
-        /// Gets the name of the node, e.g. "active", "valueQuantity".
-        /// </summary>
-        /// <remarks>Since the node has no type information, choice elements are represented as their 
-        /// name on the wire, possibly including the type suffix for choice elements.
-        /// </remarks>
-        string Name { get; }
+    string Name { get; }
 
-        /// <summary>
-        /// Gets the text of the primitive value of the node
-        /// </summary>
-        /// <value>Returns the raw textual value as represented in the serialization, or null if there is no value in this node.</value>
-        string Text { get; }
+    /// <summary>
+    /// Gets the text of the primitive value of the node
+    /// </summary>
+    /// <value>Returns the raw textual value as represented in the serialization, or null if there is no value in this node.</value>
+    string Text { get; }
 
-        /// <summary>
-        /// Gets the location of this node within the tree of data.
-        /// </summary>
-        /// <value>A string of dot-separated names representing the path to the node within the tree, including indices
-        /// to distinguish repeated occurences of an element.</value>
-        string Location { get; }
+    /// <summary>
+    /// Gets the location of this node within the tree of data.
+    /// </summary>
+    /// <value>A string of dot-separated names representing the path to the node within the tree, including indices
+    /// to distinguish repeated occurences of an element.</value>
+    string Location { get; }
 
-        /// <summary>
-        /// Enumerates the direct child nodes of the current node (if any).
-        /// </summary>
-        /// <param name="name">Optional. The name filter for the children. Can be omitted to not filter by name.</param>
-        /// <returns>The children of the node matching the given filter, or all children if no filter was specified.
-        /// If no children match the given filter, the function returns an empty enumerable.</returns>
-        /// <remarks>
-        /// <para>If the <paramref name="name"/>parameter ends in an asterix ('*'),
-        /// the function will return the children of which the name starts with the given name.</para>
-        /// <para>Repeating elements will always be returned consecutively.</para></remarks>
-        IEnumerable<ISourceNode> Children(string name = null);
-    }
+    /// <summary>
+    /// Enumerates the direct child nodes of the current node (if any).
+    /// </summary>
+    /// <param name="name">Optional. The name filter for the children. Can be omitted to not filter by name.</param>
+    /// <returns>The children of the node matching the given filter, or all children if no filter was specified.
+    /// If no children match the given filter, the function returns an empty enumerable.</returns>
+    /// <remarks>
+    /// <para>If the <paramref name="name"/>parameter ends in an asterix ('*'),
+    /// the function will return the children of which the name starts with the given name.</para>
+    /// <para>Repeating elements will always be returned consecutively.</para></remarks>
+    IEnumerable<ISourceNode> Children(string name = null);
 }

src/Hl7.Fhir.Base/ElementModel/PocoNodeExtensions.cs

@@ -1,6 +1,7 @@
 using Hl7.Fhir.Introspection;
 using Hl7.Fhir.Model;
 using Hl7.Fhir.Rest;
+using Hl7.Fhir.Serialization;
 using Hl7.Fhir.Utility;
 using System;
 using System.Collections.Generic;
@@ -288,4 +289,16 @@ internal static IEnumerable<PocoNode> Where<T>(this PocoListNode pln, Func<T, bo
     }
 
     internal static ModelInspector? FindInspector(this PocoNode node) => ((IAnnotated)node).Annotation<ModelInspector>() ?? node.Parent?.SingleOrDefault()?.FindInspector();
+
+    internal static string SerializeToString(this PocoNode pn, bool pretty)
+    {
+        var serializer = new BaseFhirXmlSerializer(pn.FindInspector() ?? ModelInspector.ForType(pn.Poco.GetType()));
+
+        // If we are serializing a subtree of a resource, then if the current node is a datatype or a nested resource,
+        // we need to pick a name for this root element.
+        var pickElementName = pn.Poco is not Resource || pn.Parent is not null;
+        var rootName = pickElementName ? pn.Name : null;
+
+        return serializer.SerializeToString(pn.Poco, pretty, rootName: rootName);
+    }
 }