diff --git a/src/emitter.cpp b/src/emitter.cpp
index 06f633c..1241518 100644
--- a/src/emitter.cpp
+++ b/src/emitter.cpp
@@ -677,7 +677,7 @@ Emitter& Emitter::Write(const std::string& str) {
     return *this;
 
   const bool escapeNonAscii = m_pState->GetOutputCharset() == EscapeNonAscii;
-  const StringFormat::value strFormat =
+  const StringFormat strFormat =
       Utils::ComputeStringFormat(str, m_pState->GetStringFormat(),
                                  m_pState->CurGroupFlowType(), escapeNonAscii);
 
diff --git a/src/emitterutils.cpp b/src/emitterutils.cpp
index 78fb5bf..e155a49 100644
--- a/src/emitterutils.cpp
+++ b/src/emitterutils.cpp
@@ -260,7 +260,7 @@ bool WriteAliasName(ostream_wrapper& out, const std::string& str) {
 }
 }  // namespace
 
-StringFormat::value ComputeStringFormat(const std::string& str,
+StringFormat ComputeStringFormat(const std::string& str,
                                         EMITTER_MANIP strFormat,
                                         FlowType flowType,
                                         bool escapeNonAscii) {
diff --git a/src/emitterutils.h b/src/emitterutils.h
index 2333e7b..c593ec9 100644
--- a/src/emitterutils.h
+++ b/src/emitterutils.h
@@ -20,12 +20,15 @@ class ostream_wrapper;
 namespace YAML {
 class Binary;
 
-struct StringFormat {
-  enum value { Plain, SingleQuoted, DoubleQuoted, Literal };
+enum class StringFormat {
+  Plain,
+  SingleQuoted,
+  DoubleQuoted,
+  Literal
 };
 
 namespace Utils {
-StringFormat::value ComputeStringFormat(const std::string& str,
+StringFormat ComputeStringFormat(const std::string& str,
                                         EMITTER_MANIP strFormat,
                                         FlowType flowType,
                                         bool escapeNonAscii);