12 files changed, 16 insertions, 32 deletions
diff --git a/src/function/base.h b/src/function/base.h
index 7c2043e..c3e1fb6 100644
--- a/src/function/base.h
+++ b/src/function/base.h
@@ -104,9 +104,7 @@ class FunctionBase : public xalan::Function {
 			);
 
 			return this->document_cache_->create(
-				static_cast<Implementation*>(
-					const_cast<FunctionBase*>(this)
-				)->constructDocument(
+				static_cast<const Implementation*>(this)->constructDocument(
 					valueGetter.get<typename std::tuple_element<
 						Index,
 						std::tuple<Types...>
diff --git a/src/function/external_text_formatter.cc b/src/function/external_text_formatter.cc
index ccf7ee7..048f81a 100644
--- a/src/function/external_text_formatter.cc
+++ b/src/function/external_text_formatter.cc
@@ -42,7 +42,7 @@ namespace InputXSLT {
 DomDocumentCache::document_ptr FunctionExternalTextFormatter::constructDocument(
 	boost::filesystem::path formatterPath,
 	std::string             stdinText
-) {
+) const {
 	DomDocumentCache::document_ptr domDocument(
 		DomDocumentCache::createDocument("content")
 	);
diff --git a/src/function/external_text_formatter.h b/src/function/external_text_formatter.h
index 23e6ab9..27f2fc7 100644
--- a/src/function/external_text_formatter.h
+++ b/src/function/external_text_formatter.h
@@ -21,7 +21,7 @@ class FunctionExternalTextFormatter : public FunctionBase<
 		DomDocumentCache::document_ptr constructDocument(
 			boost::filesystem::path,
 			std::string
-		);
+		) const;
 
 };
 
diff --git a/src/function/read_directory.cc b/src/function/read_directory.cc
index 9b84828..8436459 100644
--- a/src/function/read_directory.cc
+++ b/src/function/read_directory.cc
@@ -6,7 +6,7 @@
 namespace InputXSLT {
 
 DomDocumentCache::document_ptr FunctionReadDirectory::constructDocument(
-	boost::filesystem::path directoryPath) {
+	boost::filesystem::path directoryPath) const {
 	DomDocumentCache::document_ptr domDocument(
 		DomDocumentCache::createDocument("content")
 	);
diff --git a/src/function/read_directory.h b/src/function/read_directory.h
index 59ece1a..914f9b3 100644
--- a/src/function/read_directory.h
+++ b/src/function/read_directory.h
@@ -18,7 +18,7 @@ class FunctionReadDirectory : public FunctionBase<
 		friend FunctionBase;
 
 		DomDocumentCache::document_ptr constructDocument(
-			boost::filesystem::path);
+			boost::filesystem::path) const;
 
 };
 
diff --git a/src/function/read_file.cc b/src/function/read_file.cc
index 0ca5ee3..42cb4a4 100644
--- a/src/function/read_file.cc
+++ b/src/function/read_file.cc
@@ -60,7 +60,7 @@ boost::optional<std::string> readPlainFile(
 namespace InputXSLT {
 
 DomDocumentCache::document_ptr FunctionReadFile::constructDocument(
-	boost::filesystem::path filePath) {
+	boost::filesystem::path filePath) const {
 	DomDocumentCache::document_ptr domDocument(
 		DomDocumentCache::createDocument("content")
 	);
diff --git a/src/function/read_file.h b/src/function/read_file.h
index 3026c79..b26bc6a 100644
--- a/src/function/read_file.h
+++ b/src/function/read_file.h
@@ -18,7 +18,7 @@ class FunctionReadFile : public FunctionBase<
 		friend FunctionBase;
 
 		DomDocumentCache::document_ptr constructDocument(
-			boost::filesystem::path);
+			boost::filesystem::path) const;
 
 };
 
diff --git a/src/function/transform.cc b/src/function/transform.cc
index 6cda7a7..7eab3fd 100644
--- a/src/function/transform.cc
+++ b/src/function/transform.cc
@@ -7,29 +7,12 @@
 #include "support/dom/result_node_facade.h"
 #include "support/error/error_capacitor.h"
 
-namespace {
-
-using InputXSLT::ErrorCapacitor;
-
-inline void handleErrors(
-	InputXSLT::ResultNodeFacade&       result,
-	const ErrorCapacitor::error_cache& errors
-) {
-	result.setAttribute("result", "error");
-
-	for ( auto&& error : errors ) {
-		result.setValueNode("error", error);
-	}
-}
-
-}
-
 namespace InputXSLT {
 
 DomDocumentCache::document_ptr FunctionTransform::constructDocument(
 	xalan::XSLTInputSource  inputSource,
 	xalan::XSLTInputSource  transformationSource
-) {
+) const {
 	DomDocumentCache::document_ptr domDocument(
 		DomDocumentCache::createDocument("content")
 	);
@@ -52,7 +35,11 @@ DomDocumentCache::document_ptr FunctionTransform::constructDocument(
 		result.setAttribute("result", "success");
 	}
 	catch (const ErrorCapacitor::exception& exception) {
-		handleErrors(result, *exception);
+		result.setAttribute("result", "error");
+
+		for ( auto&& error : *exception ) {
+			result.setValueNode("error", error);
+		}
 	}
 
 	WarningCapacitor::warning_cache_ptr warnings(
diff --git a/src/function/transform.h b/src/function/transform.h
index 95acba3..48f5c89 100644
--- a/src/function/transform.h
+++ b/src/function/transform.h
@@ -21,7 +21,7 @@ class FunctionTransform : public FunctionBase<
 		DomDocumentCache::document_ptr constructDocument(
 			xalan::XSLTInputSource,
 			xalan::XSLTInputSource
-		);
+		) const;
 
 };
 
diff --git a/src/function/write_file.cc b/src/function/write_file.cc
index 3df9d78..06fdcfd 100644
--- a/src/function/write_file.cc
+++ b/src/function/write_file.cc
@@ -60,7 +60,7 @@ namespace InputXSLT {
 DomDocumentCache::document_ptr FunctionWriteFile::constructDocument(
 	boost::filesystem::path filePath,
 	xalan::XalanNode* const contentNode
-) {
+) const {
 	DomDocumentCache::document_ptr domDocument(
 		DomDocumentCache::createDocument("content")
 	);
diff --git a/src/function/write_file.h b/src/function/write_file.h
index c1d6100..723865e 100644
--- a/src/function/write_file.h
+++ b/src/function/write_file.h
@@ -19,7 +19,7 @@ class FunctionWriteFile : public FunctionBase<
 		DomDocumentCache::document_ptr constructDocument(
 			boost::filesystem::path,
 			xalan::XalanNode* const
-		);
+		) const;
 
 };
 
diff --git a/src/transformer_facade.h b/src/transformer_facade.h
index 14d2f41..dfe6123 100644
--- a/src/transformer_facade.h
+++ b/src/transformer_facade.h
@@ -46,7 +46,6 @@ class TransformerFacade {
 			xalan::FormatterListener&
 		);
 
-
 };
 
 }