From 7b94f1e45016d85b58f705e3b9bd8cd40d9aca15 Mon Sep 17 00:00:00 2001
From: Daniel Carbone <daniel.p.carbone@gmail.com>
Date: Tue, 28 Jan 2025 11:45:45 -0600
Subject: [PATCH] its currently broken, but lots of work towards better xml
 serialization

---
 files/constants.php                           |   6 +-
 src/Utilities/ImportUtils.php                 |  42 +++++--
 src/Version/Definition/Property.php           |  20 +--
 src/Version/Definition/Type.php               |  63 +++++++---
 .../core/encoding/enum_value_xml_location.php |   3 +-
 .../core/types/interface_contained_type.php   |  14 ++-
 .../core/types/interface_element_type.php     |  85 +++++++++++++
 .../interface_primitive_container_type.php    |  79 ++++++++++++
 .../core/types/interface_primitive_type.php   |  34 +----
 .../core/types/interface_resource_type.php    |  85 +++++++++++++
 template/core/types/interface_type.php        |  52 +-------
 template/versions/types/class_default.php     |  81 +++++++-----
 .../types/properties/methods/default.php      |  28 ++++-
 .../serialization/json/unserialize/header.php |  22 +++-
 .../serialization/xml/serialize/body.php      | 119 +++++++++++-------
 .../serialization/xml/serialize/header.php    |  17 ++-
 .../serialization/xml/unserialize/body.php    |   4 +-
 .../serialization/xml/unserialize/header.php  |  19 ++-
 .../versions/types/validation/methods.php     |   2 +-
 19 files changed, 545 insertions(+), 230 deletions(-)
 create mode 100644 template/core/types/interface_element_type.php
 create mode 100644 template/core/types/interface_primitive_container_type.php
 create mode 100644 template/core/types/interface_resource_type.php

diff --git a/files/constants.php b/files/constants.php
index eb6bc735..53c078d0 100644
--- a/files/constants.php
+++ b/files/constants.php
@@ -108,9 +108,13 @@
 
 // Core types entities
 const PHPFHIR_TYPES_INTERFACE_TYPE = 'TypeInterface';
+const PHPFHIR_TYPES_INTERFACE_PRIMITIVE_TYPE = 'PrimitiveTypeInterface';
+const PHPFHIR_TYPES_INTERFACE_PRIMITIVE_CONTAINER_TYPE = 'PrimitiveContainerTypeInterface';
+const PHPFHIR_TYPES_INTERFACE_ELEMENT_TYPE = 'ElementTypeInterface';
+const PHPFHIR_TYPES_INTERFACE_RESOURCE_TYPE = 'ResourceTypeInterface';
+
 const PHPFHIR_TYPES_INTERFACE_CONTAINED_TYPE = 'ContainedTypeInterface';
 const PHPFHIR_TYPES_INTERFACE_COMMENT_CONTAINER = 'CommentContainerInterface';
-const PHPFHIR_TYPES_INTERFACE_PRIMITIVE_TYPE = 'PrimitiveTypeInterface';
 const PHPFHIR_TYPES_TRAIT_COMMENT_CONTAINER = 'CommentContainerTrait';
 
 
diff --git a/src/Utilities/ImportUtils.php b/src/Utilities/ImportUtils.php
index 0fcac075..75ca521c 100644
--- a/src/Utilities/ImportUtils.php
+++ b/src/Utilities/ImportUtils.php
@@ -82,13 +82,11 @@ public static function buildVersionTypeImports(Version $version, Type $type): vo
 
         $typeKind = $type->getKind();
 
-        if (!$type->isAbstract()) {
+        if (!$type->isAbstract() && !$type->isPrimitiveOrListType()) {
             $imports->addCoreFileImportsByName(
                 PHPFHIR_ENCODING_CLASSNAME_XML_WRITER,
-                PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION,
                 PHPFHIR_ENCODING_CLASSNAME_UNSERIALIZE_CONFIG,
                 PHPFHIR_ENCODING_CLASSNAME_SERIALIZE_CONFIG,
-                PHPFHIR_TYPES_INTERFACE_TYPE,
             );
         }
 
@@ -100,6 +98,28 @@ public static function buildVersionTypeImports(Version $version, Type $type): vo
             $imports->addImport($namespace, $trait);
         }
 
+        if ($type->isPrimitiveOrListType() || $type->hasPrimitiveOrListParent()) {
+
+        } else if ($type->isPrimitiveContainer() || $type->hasPrimitiveContainerParent()) {
+            $imports->addCoreFileImportsByName(
+                PHPFHIR_TYPES_INTERFACE_ELEMENT_TYPE,
+            );
+        } else if ($type->isResourceType() || $type->hasResourceTypeParent()) {
+            $imports->addCoreFileImportsByName(
+                PHPFHIR_TYPES_INTERFACE_RESOURCE_TYPE,
+            );
+        } else {
+            $imports->addCoreFileImportsByName(
+                PHPFHIR_TYPES_INTERFACE_ELEMENT_TYPE,
+            );
+        }
+
+        if ($type->isValueContainer() || $type->hasValueContainerParent()) {
+            $imports->addCoreFileImportsByName(
+                PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION,
+            );
+        }
+
         $imports->addVersionCoreFileImportsByName(
             $type->getVersion(),
             PHPFHIR_VERSION_CLASSNAME_VERSION,
@@ -130,10 +150,6 @@ public static function buildVersionTypeImports(Version $version, Type $type): vo
             );
         }
 
-        if ($type->isPrimitiveOrListType() || $type->isValueContainer() || $type->isPrimitiveContainer()) {
-            $imports->addCoreFileImportsByName(PHPFHIR_ENCODING_TRAIT_VALUE_XML_LOCATION);
-        }
-
         if ($restrictionBaseType = $type->getRestrictionBaseFHIRType()) {
             $imports->addImport(
                 $restrictionBaseType->getFullyQualifiedNamespace(false),
@@ -147,6 +163,10 @@ public static function buildVersionTypeImports(Version $version, Type $type): vo
                 continue;
             }
 
+            if ($property->isSerializableAsXMLAttribute()) {
+                $imports->addCoreFileImportsByName(PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION);
+            }
+
             $ptk = $propertyType->getKind();
 
 //            if (null !== $property->getOverloadedProperty() && !$ptk->isOneOf(TypeKindEnum::PRIMITIVE, TypeKindEnum::LIST)) {
@@ -166,8 +186,12 @@ public static function buildVersionTypeImports(Version $version, Type $type): vo
                 $imports->addVersionCoreFileImportsByName($type->getVersion(), PHPFHIR_VERSION_CLASSNAME_VERSION);
             } else {
                 if ($ptk === TypeKindEnum::PRIMITIVE_CONTAINER) {
-                    $primType = $propertyType->getProperties()->getProperty(PHPFHIR_VALUE_PROPERTY_NAME)->getValueFHIRType();
-                    $imports->addImport($primType->getFullyQualifiedNamespace(false), $primType->getClassName());
+                    $primType = $propertyType
+                        ->getProperties()
+                        ->getProperty(PHPFHIR_VALUE_PROPERTY_NAME)->getValueFHIRType();
+                    $imports->addImport(
+                        $primType->getFullyQualifiedNamespace(false), $primType->getClassName()
+                    );
                 }
 
                 $imports->addImport(
diff --git a/src/Version/Definition/Property.php b/src/Version/Definition/Property.php
index 2afe1ef3..e59084a0 100644
--- a/src/Version/Definition/Property.php
+++ b/src/Version/Definition/Property.php
@@ -500,11 +500,11 @@ public function getOverloadedProperty(): null|Property
     }
 
     /**
-     * This method will panic if this is a primitive type.  Deal with it, also make it better later.
+     * Returns true if this property may be represented as an XML attribute on the parent element.
      *
      * @return bool
      */
-    public function requiresXMLLocation(): bool
+    public function isSerializableAsXMLAttribute(): bool
     {
         $propType = $this->getValueFHIRType();
         if (null === $propType || $this->isCollection()) {
@@ -515,22 +515,6 @@ public function requiresXMLLocation(): bool
             || $propType->isPrimitiveOrListType();
     }
 
-    /**
-     * @return string
-     */
-    public function defaultXMLLocationEnumValue(): string
-    {
-        if (!$this->requiresXMLLocation()) {
-            throw new \RuntimeException(sprintf(
-                'Type "%s" property "%s" does not support XML location setting',
-                $this->getMemberOf()->getFHIRName(),
-                $this->getName(),
-            ));
-        }
-
-        return $this->getValueFHIRType()->isValueContainer() ? 'ELEMENT' : 'ATTRIBUTE';
-    }
-
     /**
      * @return string
      */
diff --git a/src/Version/Definition/Type.php b/src/Version/Definition/Type.php
index ceab2482..a9c28387 100644
--- a/src/Version/Definition/Type.php
+++ b/src/Version/Definition/Type.php
@@ -569,7 +569,15 @@ public function hasPrimitiveContainerParent(): bool
      */
     public function isResourceType(): bool
     {
-        return str_contains($this->getFullyQualifiedNamespace(false), '\\FHIRResource\\');
+        return $this->_fhirName === 'Resource'
+            || $this->_fhirName === 'DomainResource'
+            || str_contains($this->getFullyQualifiedNamespace(false), '\\FHIRResource\\')
+            || str_contains($this->getFullyQualifiedNamespace(false), '\\FHIRDomainResource\\');
+    }
+
+    public function hasResourceTypeParent(): bool
+    {
+        return $this->hasParent() && $this->_parentType->isResourceType();
     }
 
     /**
@@ -776,6 +784,14 @@ public function setContainedType(bool $containedType): Type
         return $this;
     }
 
+    /**
+     * @return bool
+     */
+    public function hasContainedTypeParent(): bool
+    {
+        return $this->hasParent() && $this->_parentType->isContainedType();
+    }
+
     /**
      * @return bool
      */
@@ -817,30 +833,43 @@ public function hasValueContainerParent(): bool
     public function getDirectlyImplementedInterfaces(): array
     {
         $interfaces = [];
-        $parentType = $this->getParentType();
         $coreFiles = $this->_version->getConfig()->getCoreFiles();
         $versionCoreFiles = $this->_version->getCoreFiles();
 
-        if (null === $parentType) {
-            if ($this->isCommentContainer()) {
-                $interfaces[PHPFHIR_TYPES_INTERFACE_COMMENT_CONTAINER] = $coreFiles
-                    ->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_COMMENT_CONTAINER)
-                    ->getFullyQualifiedNamespace(false);
-            }
-            if ($this->isContainedType()) {
-                $interfaces[PHPFHIR_VERSION_INTERFACE_VERSION_CONTAINED_TYPE] = $versionCoreFiles
-                    ->getCoreFileByEntityName(PHPFHIR_VERSION_INTERFACE_VERSION_CONTAINED_TYPE)
-                    ->getFullyQualifiedNamespace(false);
-            } else if ($this->getKind() === TypeKindEnum::PRIMITIVE) {
+        // first, determine which base type interface it must implement
+        if ($this->isPrimitiveOrListType()) {
+            if (!$this->hasPrimitiveOrListParent()) {
                 $interfaces[PHPFHIR_TYPES_INTERFACE_PRIMITIVE_TYPE] = $coreFiles
                     ->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_PRIMITIVE_TYPE)
                     ->getFullyQualifiedNamespace(false);
-            } else {
-                $interfaces[PHPFHIR_TYPES_INTERFACE_TYPE] = $coreFiles
-                    ->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_TYPE)
+            }
+        } else if ($this->isPrimitiveContainer()) {
+            if (!$this->hasPrimitiveContainerParent()) {
+                $interfaces[PHPFHIR_TYPES_INTERFACE_PRIMITIVE_CONTAINER_TYPE] = $coreFiles
+                    ->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_PRIMITIVE_CONTAINER_TYPE)
+                    ->getFullyQualifiedNamespace(false);
+            }
+        } else if ($this->isResourceType()) {
+            if (!$this->hasResourceTypeParent()) {
+                $interfaces[PHPFHIR_TYPES_INTERFACE_RESOURCE_TYPE] = $coreFiles
+                    ->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_RESOURCE_TYPE)
                     ->getFullyQualifiedNamespace(false);
             }
-        } elseif ($this->isContainedType() && !$parentType->isContainedType()) {
+        } else if (!$this->hasParent()) {
+            $interfaces[PHPFHIR_TYPES_INTERFACE_ELEMENT_TYPE] = $coreFiles
+                ->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_ELEMENT_TYPE)
+                ->getFullyQualifiedNamespace(false);
+        }
+
+        // comment container types
+        if ($this->isCommentContainer() && !$this->hasCommentContainerParent()) {
+            $interfaces[PHPFHIR_TYPES_INTERFACE_COMMENT_CONTAINER] = $coreFiles
+                ->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_COMMENT_CONTAINER)
+                ->getFullyQualifiedNamespace(false);
+        }
+
+        // types that can be contained within a resource container type
+        if ($this->isContainedType() && !$this->hasContainedTypeParent()) {
             $interfaces[PHPFHIR_VERSION_INTERFACE_VERSION_CONTAINED_TYPE] = $versionCoreFiles
                 ->getCoreFileByEntityName(PHPFHIR_VERSION_INTERFACE_VERSION_CONTAINED_TYPE)
                 ->getFullyQualifiedNamespace(false);
diff --git a/template/core/encoding/enum_value_xml_location.php b/template/core/encoding/enum_value_xml_location.php
index 3df71246..7ea41989 100644
--- a/template/core/encoding/enum_value_xml_location.php
+++ b/template/core/encoding/enum_value_xml_location.php
@@ -28,7 +28,8 @@
 
 enum <?php echo PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION; ?> : string
 {
-    case ATTRIBUTE = 'attribute';
+    case PARENT_ATTRIBUTE = 'parent_attribute';
+    case LOCAL_ATTRIBUTE = 'local_attribute';
     case ELEMENT = 'element';
 }
 <?php return ob_get_clean();
diff --git a/template/core/types/interface_contained_type.php b/template/core/types/interface_contained_type.php
index 3dee098a..b1298d8c 100644
--- a/template/core/types/interface_contained_type.php
+++ b/template/core/types/interface_contained_type.php
@@ -16,9 +16,17 @@
  * limitations under the License.
  */
 
+use DCarbone\PHPFHIR\Utilities\ImportUtils;
+
 /** @var \DCarbone\PHPFHIR\Config $config */
 /** @var \DCarbone\PHPFHIR\CoreFile $coreFile */
 
+$coreFiles = $config->getCoreFiles();
+$resourceTypeInterface = $coreFiles->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_RESOURCE_TYPE);
+
+$imports = $coreFile->getImports();
+$imports->addCoreFileImports($resourceTypeInterface);
+
 ob_start();
 echo '<?php ';?>declare(strict_types=1);
 
@@ -26,14 +34,16 @@
 
 <?php echo $config->getBasePHPFHIRCopyrightComment(true); ?>
 
+<?php echo ImportUtils::compileImportStatements($imports); ?>
+
 /**
- * Interface <?php echo PHPFHIR_TYPES_INTERFACE_CONTAINED_TYPE; ?>
+ * Interface <?php echo $coreFile->getEntityName(); ?>
 
  *
  * This is a meta interface that must never be directly implemented by a class.  It exists purely to ensure type safety
  * throughout the base package.
  */
-interface <?php echo PHPFHIR_TYPES_INTERFACE_CONTAINED_TYPE; ?> extends <?php echo PHPFHIR_TYPES_INTERFACE_TYPE; ?>
+interface <?php echo $coreFile->getEntityName(); ?> extends <?php echo $resourceTypeInterface->getEntityName(); ?>
 
 {
     /**
diff --git a/template/core/types/interface_element_type.php b/template/core/types/interface_element_type.php
new file mode 100644
index 00000000..4d317e97
--- /dev/null
+++ b/template/core/types/interface_element_type.php
@@ -0,0 +1,85 @@
+<?php declare(strict_types=1);
+
+/*
+ * Copyright 2025 Daniel Carbone (daniel.p.carbone@gmail.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/** @var \DCarbone\PHPFHIR\Config $config */
+/** @var \DCarbone\PHPFHIR\CoreFile $coreFile */
+
+use DCarbone\PHPFHIR\Utilities\ImportUtils;
+
+$coreFiles = $config->getCoreFiles();
+
+$typeInterface = $coreFiles->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_TYPE);
+$serializeConfigClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_SERIALIZE_CONFIG);
+$unserializeConfigClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_UNSERIALIZE_CONFIG);
+$xmlWriterClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_XML_WRITER);
+
+$imports = $coreFile->getimports();
+
+$imports->addCoreFileImports($typeInterface, $serializeConfigClass, $unserializeConfigClass, $xmlWriterClass);
+
+ob_start();
+echo '<?php ';?>declare(strict_types=1);
+
+namespace <?php echo $coreFile->getFullyQualifiedNamespace(false); ?>;
+
+<?php echo $config->getBasePHPFHIRCopyrightComment(true); ?>
+
+<?php echo ImportUtils::compileImportStatements($imports); ?>
+
+interface <?php echo $coreFile->getEntityName(); ?> extends <?php echo $typeInterface->getEntityName(); ?>, \JsonSerializable
+
+{
+    /**
+     * Returns the root XMLNS value found in the source.  Null indicates no "xmlns" was found.  Only defined when
+     * unserializing XML, and only used when serializing XML.
+     *
+     * @return null|string
+     */
+    public function _getSourceXMLNS(): null|string;
+
+    /**
+     * @param string|\SimpleXMLElement $element
+     * @param null|<?php echo $coreFile->getFullyQualifiedName(true); ?> $type Instance of this class to unserialize into.  If left null, a new instance will be created.
+     * @param null|<?php echo $unserializeConfigClass->getFullyQualifiedName(true); ?> $config
+     * @return static
+     */
+    public static function xmlUnserialize(string|\SimpleXMLElement $element,
+                                          null|<?php echo $coreFile->getEntityName(); ?> $type = null,
+                                          null|<?php echo $unserializeConfigClass->getEntityName() ?> $config = null): self;
+
+    /**
+     * @param null|<?php echo $xmlWriterClass->getFullyQualifiedName(true); ?> $xw
+     * @param null|<?php echo $serializeConfigClass->getFullyQualifiedName(true); ?> $config
+     * @return <?php echo $xmlWriterClass->getFullyQualifiedName(true); ?>
+
+     */
+    public function xmlSerialize(null|<?php echo $xmlWriterClass->getEntityName(); ?> $xw = null,
+                                 null|<?php echo $serializeConfigClass->getEntityName(); ?> $config = null): <?php echo $xmlWriterClass->getEntityName(); ?>;
+
+    /**
+     * @param string|array|\stdClass $json Raw or already un-encoded JSON
+     * @param null|<?php echo $coreFile->getFullyQualifiedName(true); ?> $type Instance of this class to unserialize into.  If left null, a new instance will be created.
+     * @param null|<?php echo $unserializeConfigClass->getFullyQualifiedName(true); ?> $config
+     * @return static
+     */
+    public static function jsonUnserialize(string|array|\stdClass $json,
+                                           null|<?php echo $coreFile->getEntityName(); ?> $type = null,
+                                           null|<?php echo $unserializeConfigClass->getEntityName(); ?> $config = null): self;
+}
+
+<?php return ob_get_clean();
diff --git a/template/core/types/interface_primitive_container_type.php b/template/core/types/interface_primitive_container_type.php
new file mode 100644
index 00000000..d0cd2d2f
--- /dev/null
+++ b/template/core/types/interface_primitive_container_type.php
@@ -0,0 +1,79 @@
+<?php declare(strict_types=1);
+
+/*
+ * Copyright 2025 Daniel Carbone (daniel.p.carbone@gmail.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/** @var \DCarbone\PHPFHIR\Config $config */
+/** @var \DCarbone\PHPFHIR\CoreFile $coreFile */
+
+use DCarbone\PHPFHIR\Utilities\ImportUtils;
+
+$coreFiles = $config->getCoreFiles();
+
+$elementInterface = $coreFiles->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_ELEMENT_TYPE);
+$serializeConfigClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_SERIALIZE_CONFIG);
+$xmlWriterClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_XML_WRITER);
+$xmlValueLocationEnum = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION);
+
+$imports = $coreFile->getimports();
+
+$imports->addCoreFileImports(
+    $elementInterface,
+    $serializeConfigClass,
+    $xmlWriterClass,
+    $xmlValueLocationEnum,
+);
+
+ob_start();
+echo '<?php ';?>declare(strict_types=1);
+
+namespace <?php echo $coreFile->getFullyQualifiedNamespace(false); ?>;
+
+<?php echo $config->getBasePHPFHIRCopyrightComment(true); ?>
+
+<?php echo ImportUtils::compileImportStatements($imports); ?>
+
+interface <?php echo $coreFile->getEntityName(); ?> extends <?php echo $elementInterface->getEntityName(); ?>
+
+{
+    /**
+     * Must return the appropriate "formatted" stringified version of this type's contained primitive type's value
+     *
+     * @return string
+     */
+    public function _getFormattedValue(): string;
+
+    /**
+     * Must return true if this primitive container type has a field set other than "value".  This is used during
+     * serialization.
+     *
+     * @return bool
+     */
+    public function _nonValueFieldDefined(): bool;
+
+    /**
+     * @param null|<?php echo $xmlWriterClass->getFullyQualifiedName(true); ?> $xw
+     * @param null|<?php echo $serializeConfigClass->getFullyQualifiedName(true); ?> $config
+     * @param null|<?php echo $xmlValueLocationEnum->getFullyQualifiedName(true); ?> $valueLocation
+     * @return <?php echo $xmlWriterClass->getFullyQualifiedName(true); ?>
+
+     */
+    public function xmlSerialize(null|<?php echo $xmlWriterClass->getEntityName(); ?> $xw = null,
+                                 null|<?php echo $serializeConfigClass->getEntityName(); ?> $config = null,
+                                 null|<?php echo $xmlValueLocationEnum->getEntityName(); ?> $valueLocation = null): <?php echo $xmlWriterClass->getEntityName(); ?>;
+}
+
+<?php return ob_get_clean();
diff --git a/template/core/types/interface_primitive_type.php b/template/core/types/interface_primitive_type.php
index 5d233fab..85cc9a13 100644
--- a/template/core/types/interface_primitive_type.php
+++ b/template/core/types/interface_primitive_type.php
@@ -23,12 +23,11 @@
 
 $coreFiles = $config->getCoreFiles();
 
+$typeInterface = $coreFiles->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_TYPE);
 $valueXMLLocationEnum = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION);
 
 $imports = $coreFile->getImports();
-$imports->addCoreFileImportsByName(
-    PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION,
-);
+$imports->addCoreFileImports($typeInterface, $valueXMLLocationEnum);
 
 ob_start();
 echo '<?php ';?>declare(strict_types=1);
@@ -39,40 +38,13 @@
 
 <?php echo ImportUtils::compileImportStatements($imports); ?>
 
-interface <?php echo PHPFHIR_TYPES_INTERFACE_PRIMITIVE_TYPE; ?> extends \JsonSerializable
+interface <?php echo $coreFile->getEntityName(); ?> extends <?php echo $typeInterface->getEntityName(); ?>, \JsonSerializable
 {
-    /**
-     * Returns the FHIR name represented by this Type
-     *
-     * @return string
-     */
-    public function _getFHIRTypeName(): string;
-
-    /**
-     * Must return an associative array in structure ["field" => ["rule" => {constraint}]] to be used during validation
-     *
-     * @return array
-     */
-    public function _getValidationRules(): array;
-
-    /**
-     * Must return associative array where, if there are validation errors, the keys are the names of fields within the
-     * type that failed validation.  The value must be a string message describing the manner of error
-     *
-     * @return array
-     */
-    public function _getValidationErrors(): array;
-
     /**
      * Must return the appropriate "formatted" stringified version of this primitive type's value
      *
      * @return string
      */
     public function _getFormattedValue(): string;
-
-    /**
-     * @return string
-     */
-    public function __toString(): string;
 }
 <?php return ob_get_clean();
\ No newline at end of file
diff --git a/template/core/types/interface_resource_type.php b/template/core/types/interface_resource_type.php
new file mode 100644
index 00000000..4d317e97
--- /dev/null
+++ b/template/core/types/interface_resource_type.php
@@ -0,0 +1,85 @@
+<?php declare(strict_types=1);
+
+/*
+ * Copyright 2025 Daniel Carbone (daniel.p.carbone@gmail.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/** @var \DCarbone\PHPFHIR\Config $config */
+/** @var \DCarbone\PHPFHIR\CoreFile $coreFile */
+
+use DCarbone\PHPFHIR\Utilities\ImportUtils;
+
+$coreFiles = $config->getCoreFiles();
+
+$typeInterface = $coreFiles->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_TYPE);
+$serializeConfigClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_SERIALIZE_CONFIG);
+$unserializeConfigClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_UNSERIALIZE_CONFIG);
+$xmlWriterClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_XML_WRITER);
+
+$imports = $coreFile->getimports();
+
+$imports->addCoreFileImports($typeInterface, $serializeConfigClass, $unserializeConfigClass, $xmlWriterClass);
+
+ob_start();
+echo '<?php ';?>declare(strict_types=1);
+
+namespace <?php echo $coreFile->getFullyQualifiedNamespace(false); ?>;
+
+<?php echo $config->getBasePHPFHIRCopyrightComment(true); ?>
+
+<?php echo ImportUtils::compileImportStatements($imports); ?>
+
+interface <?php echo $coreFile->getEntityName(); ?> extends <?php echo $typeInterface->getEntityName(); ?>, \JsonSerializable
+
+{
+    /**
+     * Returns the root XMLNS value found in the source.  Null indicates no "xmlns" was found.  Only defined when
+     * unserializing XML, and only used when serializing XML.
+     *
+     * @return null|string
+     */
+    public function _getSourceXMLNS(): null|string;
+
+    /**
+     * @param string|\SimpleXMLElement $element
+     * @param null|<?php echo $coreFile->getFullyQualifiedName(true); ?> $type Instance of this class to unserialize into.  If left null, a new instance will be created.
+     * @param null|<?php echo $unserializeConfigClass->getFullyQualifiedName(true); ?> $config
+     * @return static
+     */
+    public static function xmlUnserialize(string|\SimpleXMLElement $element,
+                                          null|<?php echo $coreFile->getEntityName(); ?> $type = null,
+                                          null|<?php echo $unserializeConfigClass->getEntityName() ?> $config = null): self;
+
+    /**
+     * @param null|<?php echo $xmlWriterClass->getFullyQualifiedName(true); ?> $xw
+     * @param null|<?php echo $serializeConfigClass->getFullyQualifiedName(true); ?> $config
+     * @return <?php echo $xmlWriterClass->getFullyQualifiedName(true); ?>
+
+     */
+    public function xmlSerialize(null|<?php echo $xmlWriterClass->getEntityName(); ?> $xw = null,
+                                 null|<?php echo $serializeConfigClass->getEntityName(); ?> $config = null): <?php echo $xmlWriterClass->getEntityName(); ?>;
+
+    /**
+     * @param string|array|\stdClass $json Raw or already un-encoded JSON
+     * @param null|<?php echo $coreFile->getFullyQualifiedName(true); ?> $type Instance of this class to unserialize into.  If left null, a new instance will be created.
+     * @param null|<?php echo $unserializeConfigClass->getFullyQualifiedName(true); ?> $config
+     * @return static
+     */
+    public static function jsonUnserialize(string|array|\stdClass $json,
+                                           null|<?php echo $coreFile->getEntityName(); ?> $type = null,
+                                           null|<?php echo $unserializeConfigClass->getEntityName(); ?> $config = null): self;
+}
+
+<?php return ob_get_clean();
diff --git a/template/core/types/interface_type.php b/template/core/types/interface_type.php
index d95ab5f8..e393745d 100644
--- a/template/core/types/interface_type.php
+++ b/template/core/types/interface_type.php
@@ -16,26 +16,21 @@
  * limitations under the License.
  */
 
-
 /** @var \DCarbone\PHPFHIR\Config $config */
 /** @var \DCarbone\PHPFHIR\CoreFile $coreFile */
 
 use DCarbone\PHPFHIR\Utilities\ImportUtils;
 
-$imports = $coreFile->getImports();
-
-$imports->addCoreFileImportsByName(
-    PHPFHIR_ENCODING_CLASSNAME_SERIALIZE_CONFIG,
-    PHPFHIR_ENCODING_CLASSNAME_UNSERIALIZE_CONFIG,
-    PHPFHIR_ENCODING_CLASSNAME_XML_WRITER,
-);
-
 $coreFiles = $config->getCoreFiles();
 
 $serializeConfigClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_SERIALIZE_CONFIG);
 $unserializeConfigClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_UNSERIALIZE_CONFIG);
 $xmlWriterClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_XML_WRITER);
 
+$imports = $coreFile->getImports();
+
+$imports->addCoreFileImports($serializeConfigClass, $unserializeConfigClass, $xmlWriterClass);
+
 ob_start();
 echo '<?php ';?>declare(strict_types=1);
 
@@ -45,7 +40,7 @@
 
 <?php echo ImportUtils::compileImportStatements($imports); ?>
 
-interface <?php echo PHPFHIR_TYPES_INTERFACE_TYPE; ?> extends \JsonSerializable
+interface <?php echo $coreFile->getEntityName(); ?>
 {
     /**
      * Returns the FHIR name represented by this Type
@@ -54,14 +49,6 @@ interface <?php echo PHPFHIR_TYPES_INTERFACE_TYPE; ?> extends \JsonSerializable
      */
     public function _getFHIRTypeName(): string;
 
-    /**
-     * Returns the root XMLNS value found in the source.  Null indicates no "xmlns" was found.  Only defined when
-     * unserializing XML, and only used when serializing XML.
-     *
-     * @return null|string
-     */
-    public function _getSourceXMLNS(): null|string;
-
     /**
      * Must return an associative array in structure ["field" => ["rule" => {constraint}]] to be used during validation
      *
@@ -77,35 +64,6 @@ public function _getValidationRules(): array;
      */
     public function _getValidationErrors(): array;
 
-    /**
-     * @param string|\SimpleXMLElement $element
-     * @param null|static $type Instance of this class to unserialize into.  If left null, a new instance will be created.
-     * @param null|<?php echo $unserializeConfigClass->getFullyQualifiedName(true); ?> $config
-     * @return static
-     */
-    public static function xmlUnserialize(string|\SimpleXMLElement $element,
-                                          null|<?php echo PHPFHIR_TYPES_INTERFACE_TYPE; ?> $type = null,
-                                          null|<?php echo PHPFHIR_ENCODING_CLASSNAME_UNSERIALIZE_CONFIG ?> $config = null): self;
-
-    /**
-     * @param null|<?php echo $xmlWriterClass->getFullyQualifiedName(true); ?> $xw
-     * @param null|<?php echo $serializeConfigClass->getFullyQualifiedName(true); ?> $config
-     * @return <?php echo $xmlWriterClass->getFullyQualifiedName(true); ?>
-
-     */
-    public function xmlSerialize(null|<?php echo PHPFHIR_ENCODING_CLASSNAME_XML_WRITER; ?> $xw = null,
-                                 null|<?php echo PHPFHIR_ENCODING_CLASSNAME_SERIALIZE_CONFIG; ?> $config = null): <?php echo PHPFHIR_ENCODING_CLASSNAME_XML_WRITER; ?>;
-
-    /**
-     * @param string|array|\stdClass $json Raw or already un-encoded JSON
-     * @param null|static $type Instance of this class to unserialize into.  If left null, a new instance will be created.
-     * @param null|<?php echo $unserializeConfigClass->getFullyQualifiedName(true); ?> $config
-     * @return static
-     */
-    public static function jsonUnserialize(string|array|\stdClass $json,
-                                           null|<?php echo PHPFHIR_TYPES_INTERFACE_TYPE; ?> $type = null,
-                                           null|<?php echo PHPFHIR_ENCODING_CLASSNAME_UNSERIALIZE_CONFIG; ?> $config = null): self;
-
     /**
      * @return string
      */
diff --git a/template/versions/types/class_default.php b/template/versions/types/class_default.php
index 2a4f8cbd..64f88b5c 100644
--- a/template/versions/types/class_default.php
+++ b/template/versions/types/class_default.php
@@ -58,7 +58,31 @@
 <?php   endif;
     endforeach;
 // -- end property field name constants
+endif;
+
+// -- property validation rules
+?>
+
+    /* <?php echo basename(__FILE__) . ':' . __LINE__; ?> */
+    private static array $_validationRules = [<?php if (!$type->hasPropertiesWithValidations()): ?>];
+<?php else:
+
+    foreach ($type->getAllPropertiesIndexedIterator() as $property) :
+        $validationMap = $property->buildValidationMap($type);
+        if ([] !== $validationMap) : ?>
+
+        self::<?php echo $property->getFieldConstantName(); ?> => [
+<?php       foreach($validationMap as $k => $v) : ?>
+            <?php echo PHPFHIR_CLASSNAME_CONSTANTS; ?>::<?php echo $k; ?> => <?php echo pretty_var_export($v, 3); ?>,
+<?php       endforeach; ?>
+        ],<?php
+        endif;
+endforeach; ?>
 
+    ];
+<?php
+endif;
+// -- end property validation rules
 
 if (!$type->isPrimitiveOrListType() && !$type->hasPrimitiveOrListParent()) :
     // -- start xml location array definition
@@ -67,21 +91,21 @@
     /* <?php echo basename(__FILE__) . ':' . __LINE__; ?> */
     private array $_valueXMLLocations = [
 <?php foreach ($type->getAllPropertiesIndexedIterator() as $property) :
-        if (!$property->requiresXMLLocation()) {
+        if (!$property->isSerializableAsXMLAttribute()) {
             continue;
         } ?>
-        self::<?php echo $property->getFieldConstantName(); ?> => <?php echo $xmlLocationEnum->getEntityName(); ?>::<?php echo $property->defaultXMLLocationEnumValue(); ?>,
+        self::<?php echo $property->getFieldConstantName(); ?> => <?php echo $xmlLocationEnum->getEntityName(); ?>::ATTRIBUTE,
 <?php endforeach; ?>
     ];
 <?php
     // -- end xml location array definition
 endif;
-?>
 
-    /* <?php echo basename(__FILE__) . ':' . __LINE__; ?> */
-<?php
 // -- directly implemented properties
-    foreach ($type->getProperties()->getIterator() as $property) :
+if ($type->hasLocalProperties()) : ?>
+
+    /* <?php echo basename(__FILE__) . ':' . __LINE__; ?> */
+<?php    foreach ($type->getProperties()->getIterator() as $property) :
         $documentation = DocumentationUtils::compilePropertyDocumentation($property, 5, true); ?>
     /**<?php if ('' !== $documentation) : ?>
 
@@ -95,29 +119,6 @@
 <?php
 // -- end directly implemented properties
     endforeach;
-endif; ?>
-
-    /* <?php echo basename(__FILE__) . ':' . __LINE__; ?> */
-    /** Default validation map for fields in type <?php echo $type->getFHIRName(); ?> */
-    private const _DEFAULT_VALIDATION_RULES = [<?php if (!$type->hasPropertiesWithValidations()): ?>];
-<?php else:
-// -- property validation rules
-
-    foreach ($type->getAllPropertiesIndexedIterator() as $property) :
-        $validationMap = $property->buildValidationMap($type);
-        if ([] !== $validationMap) : ?>
-
-        self::<?php echo $property->getFieldConstantName(); ?> => [
-<?php       foreach($validationMap as $k => $v) : ?>
-            <?php echo PHPFHIR_CLASSNAME_CONSTANTS; ?>::<?php echo $k; ?> => <?php echo pretty_var_export($v, 3); ?>,
-<?php       endforeach; ?>
-        ],<?php
-        endif;
-endforeach; ?>
-
-    ];
-<?php
-// -- end property validation rules
 endif;
 
 // -- end field properties
@@ -160,8 +161,8 @@ public function _getResourceType(): string
 
     /* <?php echo basename(__FILE__) . ':' . __LINE__; ?> */
 <?php
-
-    if ($type->getKind()->isOneOf(TypeKindEnum::PRIMITIVE, TypeKindEnum::LIST)) :
+    // primitive types are different enough to warrant their own template.
+    if ($type->isPrimitiveOrListType()) :
         echo require_with(
             PHPFHIR_TEMPLATE_VERSION_TYPES_PROPERTIES_DIR . '/methods/primitive.php',
             [
@@ -183,10 +184,9 @@ public function _getResourceType(): string
 endif;
 
 if (!$type->isAbstract()) : ?>
+
     /* <?php echo basename(__FILE__) . ':' . __LINE__; ?> */
 <?php
-    echo "\n";
-
     echo require_with(
         PHPFHIR_TEMPLATE_VERSION_TYPES_VALIDATION_DIR . '/methods.php',
         [
@@ -194,7 +194,20 @@ public function _getResourceType(): string
             'type' => $type,
         ]
     );
-endif; ?>
+endif;
+
+if ($type->isPrimitiveContainer() || $type->hasPrimitiveContainerParent()) : ?>
+
+    /* <?php echo basename(__FILE__) . ':' . __LINE__; ?> */
+    public function _nonValueFieldDefined(): bool
+    {
+        return <?php foreach($type->getAllPropertiesIndexedIterator() as $i => $property) :
+            if ($property->isValueProperty()) { continue; }
+            if ($i > 0) : ?>
+
+               || <?php endif; ?>isset($this-><?php echo $property->getName(); ?>)<?php endforeach; ?>;
+    }
+<?php endif; ?>
 
     /* <?php echo basename(__FILE__) . ':' . __LINE__; ?> */
 <?php
diff --git a/template/versions/types/properties/methods/default.php b/template/versions/types/properties/methods/default.php
index 9ab79a70..909e406b 100644
--- a/template/versions/types/properties/methods/default.php
+++ b/template/versions/types/properties/methods/default.php
@@ -90,13 +90,13 @@ public function get<?php echo ucfirst($propertyName); ?>Iterator(): iterable
 
      * @param <?php echo TypeHintUtils::buildSetterParameterDocHint($version, $property, !$property->isCollection(), true); ?> $<?php echo $propertyName; ?>
 
-<?php if ($property->requiresXMLLocation()) : ?>
+<?php if ($property->isSerializableAsXMLAttribute()) : ?>
      * @param <?php echo $valueXMLLocationEnum->getFullyQualifiedName(true); ?> $valueXMLLocation
 <?php endif; ?>
      * @return static
      */
-    public function <?php echo $property->getSetterName(); ?>(<?php echo TypeHintUtils::buildSetterParameterHint($version, $property, !$property->isCollection(), true); ?> $<?php echo $property; if ($property->requiresXMLLocation()) : ?>,
-                     <?php echo str_repeat(' ', strlen($property->getSetterName())); echo $valueXMLLocationEnum->getEntityName(); ?> $valueXMLLocation = <?php echo $valueXMLLocationEnum->getEntityName(); ?>::<?php echo $property->defaultXMLLocationEnumValue(); endif ?>): self
+    public function <?php echo $property->getSetterName(); ?>(<?php echo TypeHintUtils::buildSetterParameterHint($version, $property, !$property->isCollection(), true); ?> $<?php echo $property; if ($property->isSerializableAsXMLAttribute()) : ?>,
+                     <?php echo str_repeat(' ', strlen($property->getSetterName())); echo $valueXMLLocationEnum->getEntityName(); ?> $valueXMLLocation = <?php echo $valueXMLLocationEnum->getEntityName(); ?>::ATTRIBUTE<?php endif ?>): self
     {
 <?php if (!$property->isCollection()) : ?>
         if (null === $<?php echo $propertyName; ?>) {
@@ -125,7 +125,7 @@ public function <?php echo $property->getSetterName(); ?>(<?php echo TypeHintUti
         }
 <?php endif; ?>
         $this-><?php echo $propertyName; echo $isCollection ? '[]' : ''; ?> = $<?php echo $propertyName; ?>;
-<?php if ($property->requiresXMLLocation()) : ?>
+<?php if ($property->isSerializableAsXMLAttribute()) : ?>
         $this->_valueXMLLocations[self::<?php echo $property->getFieldConstantName(); ?>] = $valueXMLLocation;
 <?php endif; ?>
         return $this;
@@ -158,7 +158,7 @@ public function set<?php echo ucfirst($propertyName); ?>(<?php echo TypeHintUtil
         return $this;
     }
 <?php   endif;
-if ($property->requiresXMLLocation()) : ?>
+if ($property->isSerializableAsXMLAttribute()) : ?>
 
     /**
      * Return the current location the "value" field of the <?php echo $property->getName(); ?> element will be placed
@@ -188,4 +188,22 @@ public function _set<?php echo ucfirst($propertyName); ?>ValueXMLLocation(<?php
 <?php endif;
 endforeach;
 
+if ($type->isPrimitiveContainer() && !$type->hasPrimitiveContainerParent()) :
+    $valueProp = $type->getProperties()->getProperty(PHPFHIR_VALUE_PROPERTY_NAME);
+    ?>
+
+    /**
+     * Return the formatted value of this type's contained primitive type.
+     *
+     * @see <?php echo $valueProp->getValueFHIRType()->getFullyQualifiedClassName(true); ?>
+
+     *
+     * @return string
+     */
+    public function _getFormattedValue(): string
+    {
+        return (string)($this->getValue()?->_getFormattedValue());
+    }
+<?php endif;
+
 return ob_get_clean();
\ No newline at end of file
diff --git a/template/versions/types/serialization/json/unserialize/header.php b/template/versions/types/serialization/json/unserialize/header.php
index e3e40cc8..9a36881b 100644
--- a/template/versions/types/serialization/json/unserialize/header.php
+++ b/template/versions/types/serialization/json/unserialize/header.php
@@ -20,10 +20,20 @@
 /** @var \DCarbone\PHPFHIR\Version\Definition\Type $type */
 
 $config = $version->getConfig();
-$coreFiles = $config->getCoreFiles();
 
+$coreFiles = $config->getCoreFiles();
+$constantsClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_CLASSNAME_CONSTANTS);
 $unserializeConfigClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_UNSERIALIZE_CONFIG);
 
+if ($type->isResourceType() || $type->hasResourceTypeParent()) {
+    $typeInterface = $coreFiles->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_RESOURCE_TYPE);
+} else {
+    $typeInterface = $coreFiles->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_ELEMENT_TYPE);
+}
+
+$versionCoreFiles = $version->getCoreFiles();
+$versionClass = $versionCoreFiles->getCoreFileByEntityName(PHPFHIR_VERSION_CLASSNAME_VERSION);
+
 ob_start(); ?>
     /**
      * @param string|array|\stdClass $json
@@ -34,8 +44,8 @@
      * @throws \Exception
      */
     public static function jsonUnserialize(string|array|\stdClass $json,
-                                           null|<?php echo PHPFHIR_TYPES_INTERFACE_TYPE; ?> $type = null,
-                                           null|<?php echo PHPFHIR_ENCODING_CLASSNAME_UNSERIALIZE_CONFIG ?> $config = null): self
+                                           null|<?php echo $typeInterface->getEntityName(); ?> $type = null,
+                                           null|<?php echo $unserializeConfigClass->getEntityName() ?> $config = null): self
     {
 <?php if ($type->isAbstract()) : // abstract types may not be instantiated directly ?>
         if (null === $type) {
@@ -52,7 +62,7 @@ public static function jsonUnserialize(string|array|\stdClass $json,
             ));
         }
         if (null === $config) {
-            $config = (new <?php echo PHPFHIR_VERSION_CLASSNAME_VERSION; ?>())->getConfig()->getUnserializeConfig();
+            $config = (new <?php echo $versionClass->getEntityName(); ?>())->getConfig()->getUnserializeConfig();
         }
         if (is_string($json)) {
             $json = json_decode(json: $json, associative: true, depth: $config->getJSONDecodeMaxDepth());
@@ -61,8 +71,8 @@ public static function jsonUnserialize(string|array|\stdClass $json,
         }
 <?php if ($type->hasConcreteParent()) : ?>
         parent::jsonUnserialize($json, $type, $config);<?php elseif (!$type->hasCommentContainerParent() && $type->isCommentContainer()) : ?>
-        if (isset($data[<?php echo PHPFHIR_CLASSNAME_CONSTANTS; ?>::JSON_FIELD_FHIR_COMMENTS])) {
-            $type->_setFHIRComments((array)$data[<?php echo PHPFHIR_CLASSNAME_CONSTANTS; ?>::JSON_FIELD_FHIR_COMMENTS]);
+        if (isset($data[<?php echo $constantsClass->getEntityName(); ?>::JSON_FIELD_FHIR_COMMENTS])) {
+            $type->_setFHIRComments((array)$data[<?php echo $constantsClass->getEntityName(); ?>::JSON_FIELD_FHIR_COMMENTS]);
         }
 <?php endif;
 
diff --git a/template/versions/types/serialization/xml/serialize/body.php b/template/versions/types/serialization/xml/serialize/body.php
index 3fca19e8..86bb27d3 100644
--- a/template/versions/types/serialization/xml/serialize/body.php
+++ b/template/versions/types/serialization/xml/serialize/body.php
@@ -21,48 +21,49 @@
 /** @var \DCarbone\PHPFHIR\Version $version */
 /** @var \DCarbone\PHPFHIR\Version\Definition\Type $type */
 
+$coreFiles = $version->getConfig()->getCoreFiles();
+
+$xmlLocationEnum = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION);
+
 ob_start();
 
 // first, marshal attribute values
 foreach ($type->getProperties()->getIterator() as $property) :
-    $propType = $property->getValueFHIRType();
+    if (!$property->isSerializableAsXMLAttribute()) {
+        continue;
+    }
 
-    $propTypeKind = $propType->getKind();
+    $propType = $property->getValueFHIRType();
 
-    if ($propType->hasPrimitiveOrListParent() || $propType->isPrimitiveOrListType()) :
-        if ($property->isCollection()) : ?>
-        if (isset($this-><?php echo $property->getName(); ?>)) {
-            foreach($this-><?php echo $property->getName(); ?> as $v) {
-                $xw->writeAttribute(self::<?php echo $property->getFieldConstantName(); ?>, $v->_getFormattedValue());
-                break;
-            }
-        }
-<?php   else : ?>
-        if (isset($this-><?php echo $property->getName(); ?>) && $this-><?php echo $property->getName(); ?>->_getValueXMLLocation() === <?php echo PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION; ?>::ATTRIBUTE) {
+    // if this is the "value" property on a primitive container, the value may be serialized to the parent's root node,
+    // to the local node's attributes, or as an element on the local node.
+    if ($type->isPrimitiveContainer() && $property->isValueProperty()) : ?>
+        if (isset($this-><?php echo $property->getName(); ?>)
+            && (<?php echo $xmlLocationEnum->getEntityName(); ?>::LOCAL_ATTRIBUTE === $valueLocation
+                || (null === $valueLocation && $this->_valueXMLLocations[self::<?php echo $property->getFieldConstantName(); ?>] === <?php echo $xmlLocationEnum->getEntityName(); ?>::LOCAL_ATTRIBUTE))) {
             $xw->writeAttribute(self::<?php echo $property->getFieldConstantName(); ?>, $this-><?php echo $property->getName(); ?>->_getFormattedValue());
         }
-<?php   endif;
-    elseif ($propType->isPrimitiveContainer()) :
-        if ($property->isCollection()) : ?>
-        if (isset($this-><?php echo $property->getName(); ?>)) {
-           foreach($this-><?php echo $property->getName(); ?> as $v) {
-                if ($v->_getValueXMLLocation() === <?php echo PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION; ?>::ATTRIBUTE) {
-                    $xw->writeAttribute(self::<?php echo $property->getFieldConstantName(); ?>, $v->getValue()?->_getFormattedValue());
-                    break;
-                }
-            }
+<?php
+    // if this is a primitive property type, the value may only be placed either as an attribute or element of the
+    // parent node.
+    elseif ($propType->hasPrimitiveOrListParent() || $propType->isPrimitiveOrListType()) : ?>
+        if (isset($this-><?php echo $property->getName(); ?>) && $this->_valueXMLLocations[self::<?php echo $property->getFieldConstantName(); ?>] === <?php echo $xmlLocationEnum->getEntityName(); ?>::PARENT_ATTRIBUTE) {
+            $xw->writeAttribute(self::<?php echo $property->getFieldConstantName(); ?>, $this-><?php echo $property->getName(); ?>->_getFormattedValue());
         }
-<?php   else: ?>
-        if (isset($this-><?php echo $property->getName(); ?>) && $this-><?php echo $property->getName(); ?>->_getValueXMLLocation() === <?php echo PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION; ?>::ATTRIBUTE) {
+<?php
+    // if this property is a value container, the value may be placed as an attribute on the parent node, an
+    // attribute on the local node, or as an element of the local node.
+    elseif ($propType->isValueContainer()) : ?>
+        if (isset($this-><?php echo $property->getName(); ?>) && $this->_valueXMLLocations[self::<?php echo $property->getFieldConstantName(); ?>] === <?php echo $xmlLocationEnum->getEntityName(); ?>::PARENT_ATTRIBUTE) {
             $xw->writeAttribute(self::<?php echo $property->getFieldConstantName(); ?>, $this-><?php echo $property->getName(); ?>->getValue()?->_getFormattedValue());
         }
-<?php   endif;
+<?php
     endif;
 endforeach;
 
 // next, marshal parent attribute & element values
 if ($type->hasConcreteParent()) : ?>
-        parent::xmlSerialize($xw, $config);
+        parent::xmlSerialize($xw, $config<?php if ($type->hasPrimitiveContainerParent()) : ?>, $valueLocation<?php endif; ?>);
 <?php endif;
 
 // finally, marshal local element values
@@ -70,9 +71,23 @@
     $propType = $property->getValueFHIRType();
     $propTypeKind = $propType->getKind();
 
-    if ($propTypeKind->isResourceContainer($version)) :
+    // value property start
+    if (!$property->isCollection() && $property->isValueProperty() && $type->isPrimitiveContainer()) : ?>
+        if (isset($this-><?php echo $property->getName(); ?>)
+            && (<?php echo $xmlLocationEnum->getEntityName(); ?>::ELEMENT === $valueLocation
+                || (null === $valueLocation
+                    && $this->_valueXMLLocations[self::<?php echo $property->getFieldConstantName(); ?>] === <?php echo $xmlLocationEnum->getEntityName(); ?>::ELEMENT))) {
+            $xw->startElement(self::<?php echo $property->getFieldConstantName(); ?>);
+            $xw->writeAttribute($this-><?php echo $property->getName(); ?>::<?php echo $property->getFieldConstantName(); ?>, $this-><?php echo $property->getName(); ?>->_getFormattedValue());
+            $xw->endElement();
+        }
+<?php
+    // value property end
+
+    // resource container start
+    elseif ($propTypeKind->isResourceContainer($version)) :
         if ($property->isCollection()) : ?>
-        if (isset($this-><?php echo $property->getName(); ?>)) {
+        if (isset($this-><?php echo $property->getName(); ?>) && [] !== $this-><?php echo $property->getName(); ?>) {
             foreach($this-><?php echo $property->getName(); ?> as $v) {
                 $xw->startElement(self::<?php echo $property->getFieldConstantName(); ?>);
                 $xw->startElement($v->_getFHIRTypeName());
@@ -90,42 +105,49 @@
             $xw->endElement();
         }
 <?php    endif;
+    // resource container end
+
+    // primitive type start
     elseif ($propType->hasPrimitiveOrListParent() || $propType->isPrimitiveOrListType()) : ?>
 <?php    if ($property->isCollection()) : ?>
-        if (isset($this-><?php echo $property->getName(); ?>)) {
+        if (isset($this-><?php echo $property->getName(); ?>) && [] !== $this-><?php echo $property->getName(); ?>) {
             foreach($this-><?php echo $property->getName(); ?> as $v) {
-                if ($v->_getValueXMLLocation() === <?php echo PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION; ?>::ELEMENT) {
-                    $xw->startElement(self::<?php echo $property->getFieldConstantName(); ?>);
-                    $xw->writeAttribute($v::FIELD_VALUE, $v->_getFormattedValue());
-                    $xw->endElement();
-                }
+                $xw->startElement(self::<?php echo $property->getFieldConstantName(); ?>);
+                $xw->writeAttribute($v::<?php echo $property->getFieldConstantName(); ?>, $v->_getFormattedValue());
+                $xw->endElement();
             }
         }
 <?php   else : ?>
-        if (isset($this-><?php echo $property->getName(); ?>) && $this-><?php echo $property->getName(); ?>->_getValueXMLLocation() === <?php echo PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION; ?>::ELEMENT) {
+        if (isset($this-><?php echo $property->getName(); ?>) && $this->_valueXMLLocations[self::<?php echo $property->getFieldConstantName(); ?>] === <?php echo $xmlLocationEnum->getEntityName(); ?>::ELEMENT) {
             $xw->startElement(self::<?php echo $property->getFieldConstantName(); ?>);
-            $xw->writeAttribute($this-><?php echo $property->getName(); ?>::FIELD_VALUE, $this-><?php echo $property->getName(); ?>->_getFormattedValue());
+            $xw->writeAttribute($this-><?php echo $property->getName(); ?>::<?php echo $property->getFieldConstantName(); ?>, $this-><?php echo $property->getName(); ?>->_getFormattedValue());
             $xw->endElement();
         }
 <?php   endif;
-    elseif ($propTypeKind === TypeKindEnum::PRIMITIVE_CONTAINER) : ?>
+    // primitive type end
+
+    // primitive container start
+    elseif ($propType->isPrimitiveContainer()) : ?>
 <?php    if ($property->isCollection()) : ?>
-        if (isset($this-><?php echo $property->getName(); ?>)) {
+        if (isset($this-><?php echo $property->getName(); ?>) && [] !== $this-><?php echo $property->getName(); ?>) {
             foreach($this-><?php echo $property->getName(); ?> as $v) {
-                if ($v->_getValueXMLLocation() === <?php echo PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION; ?>::ELEMENT) {
-                    $xw->startElement(self::<?php echo $property->getFieldConstantName(); ?>);
-                    $v->xmlSerialize($xw, $config);
-                    $xw->endElement();
-                }
+                $xw->startElement(self::<?php echo $property->getFieldConstantName(); ?>);
+                $v->xmlSerialize($xw, $config);
+                $xw->endElement();
             }
         }
 <?php   else : ?>
-        if (isset($this-><?php echo $property->getName(); ?>) && $this-><?php echo $property->getName(); ?>->_getValueXMLLocation() === <?php echo PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION; ?>::ELEMENT) {
+        if (isset($this-><?php echo $property->getName(); ?>)
+            && ($this->_valueXMLLocations[self::<?php echo $property->getFieldConstantName(); ?>] === <?php echo $xmlLocationEnum->getEntityName(); ?>::ELEMENT
+                || $this-><?php echo $property->getName(); ?>->_nonValueFieldDefined())) {
             $xw->startElement(self::<?php echo $property->getFieldConstantName(); ?>);
-            $this-><?php echo $property->getName(); ?>->xmlSerialize($xw, $config);
+            $this-><?php echo $property->getName(); ?>->xmlSerialize($xw, $config, $this->_valueXMLLocations[self::<?php echo $property->getFieldConstantName(); ?>]);
             $xw->endElement();
         }
 <?php   endif;
+    // primitive container end
+
+    // xhtml type start
     elseif ($propTypeKind === TypeKindEnum::PHPFHIR_XHTML) : ?>
         if (isset($this-><?php echo $property->getName(); ?>)) {
             $xw->startElement(self::<?php echo $property->getFieldConstantName(); ?>);
@@ -138,7 +160,11 @@
             }
             $xw->endElement();
         }
-<?php elseif ($property->isCollection()) : ?>
+<?php
+    // xhtml type end
+
+    // all other resource and element types start
+    elseif ($property->isCollection()) : ?>
         if (isset($this-><?php echo $property->getName(); ?>)) {
             foreach ($this-><?php echo $property->getName(); ?> as $v) {
                 $xw->startElement(self::<?php echo $property->getFieldConstantName(); ?>);
@@ -153,6 +179,7 @@
             $xw->endElement();
         }
 <?php
+    // all other resource and element types end
     endif;
 
 endforeach;
diff --git a/template/versions/types/serialization/xml/serialize/header.php b/template/versions/types/serialization/xml/serialize/header.php
index 273cb1f7..ed9bbd12 100644
--- a/template/versions/types/serialization/xml/serialize/header.php
+++ b/template/versions/types/serialization/xml/serialize/header.php
@@ -22,26 +22,35 @@
 /** @var \DCarbone\PHPFHIR\Version\Definition\Type $type */
 
 $config = $version->getConfig();
-$coreFiles = $config->getCoreFiles();
 
+$coreFiles = $config->getCoreFiles();
 $xmlWriterClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_XML_WRITER);
 $serializeConfigClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_SERIALIZE_CONFIG);
+$xmlLocationEnum = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_ENUM_VALUE_XML_LOCATION);
+
+$versionCoreFiles = $version->getCoreFiles();
+$versionClass = $versionCoreFiles->getCoreFileByEntityName(PHPFHIR_VERSION_CLASSNAME_VERSION);
 
 ob_start(); ?>
     /**
      * @param null|<?php echo $xmlWriterClass->getFullyQualifiedName(true); ?> $xw
      * @param null|<?php echo $serializeConfigClass->getFullyQualifiedName(true); ?> $config
+<?php if ($type->isValueContainer() || $type->hasValueContainerParent()) : ?>
+     * @param null|<?php echo $xmlLocationEnum->getFullyQualifiedName(true); ?> $valueLocation
+<?php endif; ?>
      * @return <?php echo $xmlWriterClass->getFullyQualifiedName(true); ?>
 
      */
-    public function xmlSerialize(null|<?php echo PHPFHIR_ENCODING_CLASSNAME_XML_WRITER; ?> $xw = null, null|<?php echo PHPFHIR_ENCODING_CLASSNAME_SERIALIZE_CONFIG; ?> $config = null): <?php echo PHPFHIR_ENCODING_CLASSNAME_XML_WRITER; ?>
+    public function xmlSerialize(null|<?php echo $xmlWriterClass->getEntityName(); ?> $xw = null,
+                                 null|<?php echo $serializeConfigClass->getEntityName(); ?> $config = null<?php if ($type->isPrimitiveContainer() || $type->hasPrimitiveContainerParent()) : ?>,
+                                 null|<?php echo $xmlLocationEnum->getEntityName(); ?> $valueLocation = null<?php endif; ?>): <?php echo $xmlWriterClass->getEntityName(); ?>
 
     {
         if (null === $config) {
-            $config = (new <?php echo PHPFHIR_VERSION_CLASSNAME_VERSION; ?>())->getConfig()->getSerializeConfig();
+            $config = (new <?php echo $versionClass->getEntityName(); ?>())->getConfig()->getSerializeConfig();
         }
         if (null === $xw) {
-            $xw = new <?php echo PHPFHIR_ENCODING_CLASSNAME_XML_WRITER; ?>($config);
+            $xw = new <?php echo $xmlWriterClass->getEntityName(); ?>($config);
         }
         if (!$xw->isOpen()) {
             $xw->openMemory();
diff --git a/template/versions/types/serialization/xml/unserialize/body.php b/template/versions/types/serialization/xml/unserialize/body.php
index 42e68f05..01690ca0 100644
--- a/template/versions/types/serialization/xml/unserialize/body.php
+++ b/template/versions/types/serialization/xml/unserialize/body.php
@@ -57,7 +57,7 @@
                 $type-><?php echo $setter; ?>($n);
 <?php   else :
             $propTypeClassname = $property->getMemberOf()->getImports()->getImportByType($propType); ?>
-                $type-><?php echo $setter; ?>(<?php echo $property->getName(); ?>: <?php echo $propTypeClassname; ?>::xmlUnserialize($n, null, $config)<?php if ($property->requiresXMLLocation()) : ?>, valueXMLLocation: <?php echo $valueXMLLocationEnum->getEntityName(); ?>::ELEMENT<?php endif; ?>);
+                $type-><?php echo $setter; ?>(<?php echo $property->getName(); ?>: <?php echo $propTypeClassname; ?>::xmlUnserialize($n, null, $config)<?php if ($property->isSerializableAsXMLAttribute()) : ?>, valueXMLLocation: <?php echo $valueXMLLocationEnum->getEntityName(); ?>::ELEMENT<?php endif; ?>);
 <?php   endif; ?>
             }<?php
 endforeach; ?>
@@ -84,7 +84,7 @@
             } else {
                 $type-><?php echo $setter; ?>(<?php echo $property->getName(); ?>: (string)$attributes[self::<?php echo $propConst; ?>]);
             }
-<?php if ($property->requiresXMLLocation()) : ?>
+<?php if ($property->isSerializableAsXMLAttribute()) : ?>
             $type->_set<?php echo ucfirst($property->getName()); ?>ValueXMLLocation(<?php echo $valueXMLLocationEnum->getEntityName(); ?>::ATTRIBUTE);
 <?php endif; ?>
 <?php endif; ?>
diff --git a/template/versions/types/serialization/xml/unserialize/header.php b/template/versions/types/serialization/xml/unserialize/header.php
index c25b8cdf..8279ff83 100644
--- a/template/versions/types/serialization/xml/unserialize/header.php
+++ b/template/versions/types/serialization/xml/unserialize/header.php
@@ -19,13 +19,20 @@
 /** @var \DCarbone\PHPFHIR\Version $version */
 /** @var \DCarbone\PHPFHIR\Version\Definition\Type $type */
 
-use DCarbone\PHPFHIR\Enum\TypeKindEnum;
-
 $config = $version->getConfig();
-$coreFiles = $config->getCoreFiles();
 
+$coreFiles = $config->getCoreFiles();
 $unserializeConfigClass = $coreFiles->getCoreFileByEntityName(PHPFHIR_ENCODING_CLASSNAME_UNSERIALIZE_CONFIG);
 
+if ($type->isResourceType() || $type->hasResourceTypeParent()) {
+    $typeInterface = $coreFiles->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_RESOURCE_TYPE);
+} else {
+    $typeInterface = $coreFiles->getCoreFileByEntityName(PHPFHIR_TYPES_INTERFACE_ELEMENT_TYPE);
+}
+
+$versionCoreFiles = $version->getCoreFiles();
+$versionClass = $versionCoreFiles->getCoreFileByEntityName(PHPFHIR_VERSION_CLASSNAME_VERSION);
+
 ob_start(); ?>
     /**
      * @param string|\SimpleXMLElement $element
@@ -36,8 +43,8 @@
      * @throws \Exception
      */
     public static function xmlUnserialize(string|\SimpleXMLElement $element,
-                                          null|<?php echo PHPFHIR_TYPES_INTERFACE_TYPE; ?> $type = null,
-                                          null|<?php echo PHPFHIR_ENCODING_CLASSNAME_UNSERIALIZE_CONFIG ?> $config = null): self
+                                          null|<?php echo $typeInterface->getEntityName(); ?> $type = null,
+                                          null|<?php echo $unserializeConfigClass->getEntityName() ?> $config = null): self
     {
 <?php if ($type->isAbstract()) : // abstract types may not be instantiated directly ?>
         if (null === $type) {
@@ -54,7 +61,7 @@ public static function xmlUnserialize(string|\SimpleXMLElement $element,
             ));
         }
         if (null === $config) {
-            $config = (new <?php echo PHPFHIR_VERSION_CLASSNAME_VERSION; ?>())->getConfig()->getUnserializeConfig();
+            $config = (new <?php echo $versionClass->getEntityName(); ?>())->getConfig()->getUnserializeConfig();
         }
         if (is_string($element)) {
             $element = new \SimpleXMLElement($element, $config->getLibxmlOpts());
diff --git a/template/versions/types/validation/methods.php b/template/versions/types/validation/methods.php
index 6f6e4360..b37ab00a 100644
--- a/template/versions/types/validation/methods.php
+++ b/template/versions/types/validation/methods.php
@@ -37,7 +37,7 @@
      */
     public function _getValidationRules(): array
     {
-        return self::_DEFAULT_VALIDATION_RULES;
+        return self::$_validationRules;
     }
 
     /**