Refactor FP engine against PocoNode

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/NewPocoBuilder.cs

@@ -141,7 +141,7 @@ private ClassMapping classMappingForElement(ITypedElement node, PropertyMapping?
 
         // Otherwise, let's use the ITypedElement's instance type.
         if (node.InstanceType is { } instanceType &&
-            inspector.FindClassMapping(instanceType) is { NativeType.IsAbstract: false } mapping)
+            inspector.FindClassMapping(instanceType) is { NativeType.IsAbstract: false } mapping && typeof(Base).IsAssignableFrom(mapping.NativeType))
             return mapping;
 
         // No useable concrete type in the property, nor in the instance type, so we need to create
@@ -183,7 +183,7 @@ private ClassMapping determineBestDynamicMappingForElement(ITypedElement node)
         if (node.Value is not null || (node.InstanceType is { } it && char.IsLower(it[0])))
             return determineBestPrimitiveMapping();
 
-        if (node.Annotation<IResourceTypeSupplier>() is not null)
+        if (node.Annotation<IResourceTypeSupplier>() is not null || node.Definition?.IsResource is true)
             return getClassMapping(DYNAMIC_RESOURCE_TYPE_NAME);
 
         return getClassMapping(DYNAMIC_DATATYPE_TYPE_NAME);

src/Hl7.Fhir.Base/ElementModel/PocoNode.Primitives.cs

@@ -0,0 +1,96 @@
+using Hl7.Fhir.Model;
+using Hl7.FhirPath;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+#nullable enable
+
+namespace Hl7.Fhir.ElementModel;
+
+public partial record PocoNode
+{
+    /// <summary>
+    /// Constructs a PocoNode from a PrimitiveType
+    /// </summary>
+    /// <returns></returns>
+    public static PocoNode ForPrimitive(PrimitiveType primitive) => 
+        new PrimitiveNode(primitive, null, null);
+
+
+    /// <summary>
+    /// Constructs a PocoNode from an object. Allowed objects are those that can be converted to a PrimitiveType, and are not yet PrimitiveTypes.
+    /// </summary>
+    /// <returns></returns>
+    public static PocoNode ForAnyPrimitive(object value)
+    {
+        return ForPrimitive(PrimitiveNode.InferFromValue(value));
+    }
+
+    /// <summary>
+    /// Constructs a PocoNode from a value and a type. The type must be a PrimitiveType.
+    /// </summary>
+    /// <param name="value"></param>
+    /// <typeparam name="T"></typeparam>
+    /// <returns></returns>
+    public static PocoNode ForPrimitive<T>(object value) where T : PrimitiveType, new() => 
+        new PrimitiveNode(new T { ObjectValue = value }, null, null);
+
+    /// <summary>
+    /// Constructs a PocoNode from a list of PrimitiveTypes
+    /// </summary>
+    /// <param name="primitives"></param>
+    /// <param name="name"></param>
+    /// <returns></returns>
+    public static IEnumerable<PocoNode> FromList(IEnumerable<PrimitiveType> primitives, string? name = null) => 
+        primitives.Select(ForPrimitive);
+
+    /// <summary>
+    /// Constructs multiple PocoNodes from a list of values and a type. The type must be a PrimitiveType.
+    /// </summary>
+    /// <param name="values"></param>
+    /// <typeparam name="T"></typeparam>
+    /// <returns></returns>
+    public static IEnumerable<PocoNode> FromList<T>(IEnumerable<object> values) where T : PrimitiveType, new() => 
+        values.Select(ForPrimitive<T>);
+
+    /// <summary>
+    /// Constructs multiple PocoNodes from a list of objects. Allowed objects are those that can be converted to a PrimitiveType, and are not yet PrimitiveTypes.
+    /// </summary>
+    /// <param name="values"></param>
+    /// <returns></returns>
+    public static IEnumerable<PocoNode> FromAnyList(IEnumerable<object> values) => 
+        values.Select(v => v as PocoNode ?? ForAnyPrimitive(v));
+}
+
+public record PrimitiveNode(PrimitiveType Primitive, PocoNodeOrList? ParentNode, int? Index, string? Name = null) : PocoNode(Primitive, ParentNode, Index, Name)
+{
+    protected override object? ValueInternal => Primitive.ToITypedElementValue();
+    internal object? Value => ValueInternal;
+
+    internal static PrimitiveType InferFromValue(object value) => value switch
+    {
+        Types.Quantity qt => new FPQuantity(qt),
+        Types.DateTime dt => new FPDateTime(dt),
+        Types.Date d => new FPDate(d),
+        Types.Time t => new FPTime(t),
+        decimal dec => new FPDecimal(dec),
+        float f => new FPDecimal((decimal)f),
+        double d => new FPDecimal((decimal)d),
+        bool b => new FPBoolean(b),
+        int i => new FPInteger(i),
+        long l => new FPLong(l),
+        string s => new FPString(s),
+        _ => throw new ArgumentException("Cannot infer primitive type from value", nameof(value))
+    };
+
+    protected override string? TextInternal => Primitive.ToString();
+}
+
+internal record PrimitiveListNode(IReadOnlyList<PrimitiveType> Primitives, PocoNodeOrList? ParentNode, string? Name = null) : PocoListNode(Primitives, ParentNode, Name ?? "value")
+{
+    public override IEnumerator<PocoNode> GetEnumerator() =>
+        Primitives.Select((primitive, index) => new PrimitiveNode(primitive, ParentNode, index, Name)).GetEnumerator();
+
+    internal IEnumerable<object?> Values => Primitives.Select(p => p.ObjectValue);
+}