Improved FunctionBase constructDocument parameter propagation

* replaced std::tuple constructing Mapper template methods with direct XObjectArgVectorType unpacking
** XObjectValue::get template method is applied directly using parameter pack unpacking
* implemented custom IndexSequence / Sequence type to provide vector indexes
* modified all external functions to provide matching constructDocument overloads

15 files changed, 56 insertions, 114 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c0b5b97..1aeec10 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -36,7 +36,7 @@ set(
 	src/support/error/error_multiplexer.cc
 	src/support/error/error_capacitor.cc
 	src/support/error/warning_capacitor.cc
-	src/support/tuple/xobject_value.cc
+	src/support/type/xobject_value.cc
 	src/support/dom/document_cache.cc
 	src/support/dom/document_cache_item.cc
 	src/support/dom/result_node_facade.cc
diff --git a/src/function/base.h b/src/function/base.h
index 3609201..56712bb 100644
--- a/src/function/base.h
+++ b/src/function/base.h
@@ -12,8 +12,9 @@
 #include "support/xalan_string.h"
 #include "support/filesystem_context.h"
 #include "support/include_entity_resolver.h"
-#include "support/tuple/mapper.h"
 #include "support/dom/document_cache.h"
+#include "support/type/sequence.h"
+#include "support/type/xobject_value.h"
 
 namespace InputXSLT {
 
@@ -22,18 +23,18 @@ template <
 	typename... Types
 >
 class FunctionBase : public xalan::Function {
-	public:
-		typedef std::tuple<Types...> parameter_tuple;
+	static const std::size_t parameter_count = sizeof...(Types);
 
+	public:
 		FunctionBase(IncludeEntityResolver* resolver):
 			include_resolver_(resolver),
 			document_cache_(std::make_shared<DomDocumentCache>()) { }
 
 		virtual xalan::XObjectPtr execute(
 			xalan::XPathExecutionContext& executionContext,
-			xalan::XalanNode* context,
-			const XObjectArgVectorType& parameters,
-			const xalan::Locator* locator
+			xalan::XalanNode*             context,
+			const XObjectArgVectorType&   parameters,
+			const xalan::Locator*         locator
 		) const {
 			this->validateParameters(
 				parameters,
@@ -43,25 +44,22 @@ class FunctionBase : public xalan::Function {
 			);
 
 			xalan::XalanDocument* const domDocument(
-				this->document_cache_->create(
-					static_cast<Implementation*>(
-						const_cast<FunctionBase*>(this)
-					)->constructDocument(
-						FilesystemContext(locator),
-						Mapper::template construct<parameter_tuple>(parameters)
-					)
+				this->callConstructDocument(
+					parameters,
+					locator,
+					typename IndexSequence<parameter_count>::type()
 				)
 			);
 
-			xalan::XPathExecutionContext::BorrowReturnMutableNodeRefList nodeList(
+			xalan::XPathExecutionContext::BorrowReturnMutableNodeRefList nodes(
 				executionContext
 			);
 
-			nodeList->addNodes(
+			nodes->addNodes(
 				*domDocument->getDocumentElement()->getChildNodes()
 			);
 
-			return executionContext.getXObjectFactory().createNodeSet(nodeList);
+			return executionContext.getXObjectFactory().createNodeSet(nodes);
 		}
 
 		virtual FunctionBase* clone(
@@ -84,14 +82,33 @@ class FunctionBase : public xalan::Function {
 		const xalan::XalanDOMString& getError(
 			xalan::XalanDOMString& result) const {
 			result.assign(std::string(
-				"The function expects "                                 +
-				std::to_string(std::tuple_size<parameter_tuple>::value) +
+				"The function expects "          +
+				std::to_string(parameter_count) +
 				" parameter(s)"
 			).data());
 
 			return result;
 		}
 
+		template <unsigned... Index>
+		inline xalan::XalanDocument* callConstructDocument(
+			const XObjectArgVectorType& parameters,
+			const xalan::Locator* locator,
+			Sequence<Index...>
+		) const {
+			return this->document_cache_->create(
+				static_cast<Implementation*>(
+					const_cast<FunctionBase*>(this)
+				)->constructDocument(
+					FilesystemContext(locator),
+					XObjectValue::get<typename std::tuple_element<
+						Index,
+						std::tuple<Types...>
+					>::type>(parameters[Index])...
+				)
+			);
+		}
+
 		inline void validateParameters(
 			const XObjectArgVectorType& parameters,
 			xalan::XPathExecutionContext& executionContext,
@@ -106,7 +123,7 @@ class FunctionBase : public xalan::Function {
 				}
 			);
 
-			if ( parameters.size() != std::tuple_size<parameter_tuple>::value || anyNull ) {
+			if ( parameters.size() != parameter_count || anyNull ) {
 				xalan::XPathExecutionContext::GetAndReleaseCachedString guard(
 					executionContext
 				);
diff --git a/src/function/external_text_formatter.cc b/src/function/external_text_formatter.cc
index 22f53c5..9fef439 100644
--- a/src/function/external_text_formatter.cc
+++ b/src/function/external_text_formatter.cc
@@ -44,16 +44,9 @@ namespace InputXSLT {
 
 xercesc::DOMDocument* FunctionExternalTextFormatter::constructDocument(
 	const InputXSLT::FilesystemContext&,
-	const FunctionBase::parameter_tuple& parameters
+	std::string formatterPath,
+	std::string stdinText
 ) {
-	const std::string& formatterPath(
-		std::get<0>(parameters)
-	);
-
-	const std::string& stdinText(
-		std::get<1>(parameters)
-	);
-
 	xercesc::DOMDocument* const domDocument(
 		xercesc::DOMImplementation::getImplementation()->createDocument(
 			nullptr,
diff --git a/src/function/external_text_formatter.h b/src/function/external_text_formatter.h
index 877bac5..95ff127 100644
--- a/src/function/external_text_formatter.h
+++ b/src/function/external_text_formatter.h
@@ -18,7 +18,8 @@ class FunctionExternalTextFormatter : public FunctionBase<
 
 		xercesc::DOMDocument* constructDocument(
 			const FilesystemContext&,
-			const FunctionBase::parameter_tuple&
+			std::string,
+			std::string
 		);
 
 };
diff --git a/src/function/read_directory.cc b/src/function/read_directory.cc
index e54e146..cfbe302 100644
--- a/src/function/read_directory.cc
+++ b/src/function/read_directory.cc
@@ -11,10 +11,10 @@ namespace InputXSLT {
 
 xercesc::DOMDocument* FunctionReadDirectory::constructDocument(
 	const InputXSLT::FilesystemContext& fsContext,
-	const FunctionBase::parameter_tuple& parameters
+	std::string path
 ) {
 	const boost::filesystem::path directoryPath(
-		fsContext.resolve(std::get<0>(parameters))
+		fsContext.resolve(path)
 	);
 
 	xercesc::DOMDocument* const domDocument(
diff --git a/src/function/read_directory.h b/src/function/read_directory.h
index 88fcf15..6366a09 100644
--- a/src/function/read_directory.h
+++ b/src/function/read_directory.h
@@ -17,7 +17,7 @@ class FunctionReadDirectory : public FunctionBase<
 
 		xercesc::DOMDocument* constructDocument(
 			const FilesystemContext&,
-			const FunctionBase::parameter_tuple&
+			std::string
 		);
 
 };
diff --git a/src/function/read_file.cc b/src/function/read_file.cc
index 79e321d..22e96d7 100644
--- a/src/function/read_file.cc
+++ b/src/function/read_file.cc
@@ -26,9 +26,8 @@ namespace InputXSLT {
 
 xercesc::DOMDocument* FunctionReadFile::constructDocument(
 	const FilesystemContext& fsContext,
-	const FunctionBase::parameter_tuple& parameters
+	std::string rawPath
 ) {
-	const std::string& rawPath = std::get<0>(parameters);
 	boost::filesystem::path filePath(fsContext.resolve(rawPath));
 
 	if ( !(boost::filesystem::exists(filePath) &&
diff --git a/src/function/read_file.h b/src/function/read_file.h
index cc1b662..fec8fe2 100644
--- a/src/function/read_file.h
+++ b/src/function/read_file.h
@@ -17,7 +17,7 @@ class FunctionReadFile : public FunctionBase<
 
 		xercesc::DOMDocument* constructDocument(
 			const FilesystemContext&,
-			const FunctionBase::parameter_tuple&
+			std::string
 		);
 
 };
diff --git a/src/function/read_xml_file.cc b/src/function/read_xml_file.cc
index cfa216c..65989b2 100644
--- a/src/function/read_xml_file.cc
+++ b/src/function/read_xml_file.cc
@@ -34,9 +34,8 @@ namespace InputXSLT {
 
 xercesc::DOMDocument* FunctionReadXmlFile::constructDocument(
 	const FilesystemContext& fsContext,
-	const FunctionBase::parameter_tuple& parameters
+	std::string rawPath
 ) {
-	const std::string& rawPath = std::get<0>(parameters);
 	boost::filesystem::path filePath(fsContext.resolve(rawPath));
 
 	if ( !(boost::filesystem::exists(filePath) &&
diff --git a/src/function/read_xml_file.h b/src/function/read_xml_file.h
index 6061257..7fe949a 100644
--- a/src/function/read_xml_file.h
+++ b/src/function/read_xml_file.h
@@ -17,7 +17,7 @@ class FunctionReadXmlFile : public FunctionBase<
 
 		xercesc::DOMDocument* constructDocument(
 			const FilesystemContext&,
-			const FunctionBase::parameter_tuple&
+			std::string
 		);
 
 };
diff --git a/src/function/transform.cc b/src/function/transform.cc
index 844dee9..7e6207c 100644
--- a/src/function/transform.cc
+++ b/src/function/transform.cc
@@ -30,19 +30,12 @@ namespace InputXSLT {
 
 xercesc::DOMDocument* FunctionTransform::constructDocument(
 	const InputXSLT::FilesystemContext& fsContext,
-	const FunctionBase::parameter_tuple& parameters
+	std::string                         transformationPath,
+	std::string                         targetPath,
+	xalan::XObjectPtr                   parameterObject
 ) {
-	const std::string transformationPath(
-		fsContext.resolve(std::get<0>(parameters)).string()
-	);
-
-	const std::string targetPath(
-		fsContext.resolve(std::get<1>(parameters)).string()
-	);
-
-	const xalan::XObjectPtr& parameterObject(
-		std::get<2>(parameters)
-	);
+	transformationPath = fsContext.resolve(transformationPath).string();
+	targetPath         = fsContext.resolve(targetPath).string();
 
 	xercesc::DOMDocument* const domDocument(
 		xercesc::DOMImplementation::getImplementation()->createDocument(
diff --git a/src/function/transform.h b/src/function/transform.h
index 810738e..b841750 100644
--- a/src/function/transform.h
+++ b/src/function/transform.h
@@ -19,7 +19,9 @@ class FunctionTransform : public FunctionBase<
 
 		xercesc::DOMDocument* constructDocument(
 			const FilesystemContext&,
-			const FunctionBase::parameter_tuple&
+			std::string,
+			std::string,
+			xalan::XObjectPtr
 		);
 
 };
diff --git a/src/support/tuple/mapper.h b/src/support/tuple/mapper.h
deleted file mode 100644
index 28c5f3b..0000000
--- a/src/support/tuple/mapper.h
+++ /dev/null
@@ -1,62 +0,0 @@
-#ifndef INPUTXSLT_SRC_SUPPORT_TUPLE_MAPPER_H_
-#define INPUTXSLT_SRC_SUPPORT_TUPLE_MAPPER_H_
-
-#include <xalanc/XPath/XObject.hpp>
-
-#include <tuple>
-#include <type_traits>
-
-#include "common.h"
-#include "xobject_value.h"
-
-namespace InputXSLT {
-
-template <bool Condition>
-using enable_if = typename std::enable_if<Condition, std::size_t>::type;
-
-namespace Mapper {
-	template <
-		typename Target,
-		std::size_t Index = 0,
-		typename Current  = std::tuple<>,
-		enable_if<Index == std::tuple_size<Target>::value> = 0
-	>
-	inline Target construct(
-		const xalan::XPathExecutionContext::XObjectArgVectorType&,
-		Current&& current
-	) {
-		return current;
-	}
-
-	template <
-		typename Target,
-		std::size_t Index = 0,
-		typename Current  = std::tuple<>,
-		enable_if<Index < std::tuple_size<Target>::value> = 0
-	>
-	inline Target construct(
-		const xalan::XPathExecutionContext::XObjectArgVectorType& source,
-		Current&& current = std::tuple<>()
-	) {
-		return construct<
-			Target,
-			Index + 1
-		>(
-			source,
-			std::tuple_cat(
-				current,
-				std::make_tuple(
-					XObjectValue::get<
-						typename std::tuple_element<Index, Target>::type
-					>(
-						source[Index]
-					)
-				)
-			)
-		);
-	}
-}
-
-}
-
-#endif  // INPUTXSLT_SRC_SUPPORT_TUPLE_MAPPER_H_
diff --git a/src/support/tuple/xobject_value.cc b/src/support/type/xobject_value.cc
index cdeb9c6..cdeb9c6 100644
--- a/src/support/tuple/xobject_value.cc
+++ b/src/support/type/xobject_value.cc
diff --git a/src/support/tuple/xobject_value.h b/src/support/type/xobject_value.h
index bb602a4..bb602a4 100644
--- a/src/support/tuple/xobject_value.h
+++ b/src/support/type/xobject_value.h