diff --git a/src/emitter.cpp b/src/emitter.cpp
index 644b312..08b8fdd 100644
--- a/src/emitter.cpp
+++ b/src/emitter.cpp
@@ -205,7 +205,7 @@ void Emitter::EmitBeginSeq() {
 void Emitter::EmitEndSeq() {
   if (!good())
     return;
-  FlowType::value originalType = m_pState->CurGroupFlowType();
+  FlowType originalType = m_pState->CurGroupFlowType();
 
   if (m_pState->CurGroupChildCount() == 0)
     m_pState->ForceFlow();
@@ -240,7 +240,7 @@ void Emitter::EmitBeginMap() {
 void Emitter::EmitEndMap() {
   if (!good())
     return;
-  FlowType::value originalType = m_pState->CurGroupFlowType();
+  FlowType originalType = m_pState->CurGroupFlowType();
 
   if (m_pState->CurGroupChildCount() == 0)
     m_pState->ForceFlow();
diff --git a/src/emitterstate.cpp b/src/emitterstate.cpp
index 3dbe401..9b09f17 100644
--- a/src/emitterstate.cpp
+++ b/src/emitterstate.cpp
@@ -96,7 +96,7 @@ void EmitterState::StartedNode() {
 }
 
 EmitterNodeType::value EmitterState::NextGroupType(
-    GroupType::value type) const {
+    GroupType type) const {
   if (type == GroupType::Seq) {
     if (GetFlowType(type) == Block)
       return EmitterNodeType::BlockSeq;
@@ -129,7 +129,7 @@ void EmitterState::StartedScalar() {
   ClearModifiedSettings();
 }
 
-void EmitterState::StartedGroup(GroupType::value type) {
+void EmitterState::StartedGroup(GroupType type) {
   StartedNode();
 
   const std::size_t lastGroupIndent =
@@ -156,7 +156,7 @@ void EmitterState::StartedGroup(GroupType::value type) {
   m_groups.push_back(std::move(pGroup));
 }
 
-void EmitterState::EndedGroup(GroupType::value type) {
+void EmitterState::EndedGroup(GroupType type) {
   if (m_groups.empty()) {
     if (type == GroupType::Seq) {
       return SetError(ErrorMsg::UNEXPECTED_END_SEQ);
@@ -203,11 +203,11 @@ EmitterNodeType::value EmitterState::CurGroupNodeType() const {
   return m_groups.back()->NodeType();
 }
 
-GroupType::value EmitterState::CurGroupType() const {
+GroupType EmitterState::CurGroupType() const {
   return m_groups.empty() ? GroupType::NoType : m_groups.back()->type;
 }
 
-FlowType::value EmitterState::CurGroupFlowType() const {
+FlowType EmitterState::CurGroupFlowType() const {
   return m_groups.empty() ? FlowType::NoType : m_groups.back()->flowType;
 }
 
@@ -238,7 +238,7 @@ void EmitterState::RestoreGlobalModifiedSettings() {
 }
 
 bool EmitterState::SetOutputCharset(EMITTER_MANIP value,
-                                    FmtScope::value scope) {
+                                    FmtScope scope) {
   switch (value) {
     case EmitNonAscii:
     case EscapeNonAscii:
@@ -250,7 +250,7 @@ bool EmitterState::SetOutputCharset(EMITTER_MANIP value,
   }
 }
 
-bool EmitterState::SetStringFormat(EMITTER_MANIP value, FmtScope::value scope) {
+bool EmitterState::SetStringFormat(EMITTER_MANIP value, FmtScope scope) {
   switch (value) {
     case Auto:
     case SingleQuoted:
@@ -263,7 +263,7 @@ bool EmitterState::SetStringFormat(EMITTER_MANIP value, FmtScope::value scope) {
   }
 }
 
-bool EmitterState::SetBoolFormat(EMITTER_MANIP value, FmtScope::value scope) {
+bool EmitterState::SetBoolFormat(EMITTER_MANIP value, FmtScope scope) {
   switch (value) {
     case OnOffBool:
     case TrueFalseBool:
@@ -276,7 +276,7 @@ bool EmitterState::SetBoolFormat(EMITTER_MANIP value, FmtScope::value scope) {
 }
 
 bool EmitterState::SetBoolLengthFormat(EMITTER_MANIP value,
-                                       FmtScope::value scope) {
+                                       FmtScope scope) {
   switch (value) {
     case LongBool:
     case ShortBool:
@@ -288,7 +288,7 @@ bool EmitterState::SetBoolLengthFormat(EMITTER_MANIP value,
 }
 
 bool EmitterState::SetBoolCaseFormat(EMITTER_MANIP value,
-                                     FmtScope::value scope) {
+                                     FmtScope scope) {
   switch (value) {
     case UpperCase:
     case LowerCase:
@@ -300,7 +300,7 @@ bool EmitterState::SetBoolCaseFormat(EMITTER_MANIP value,
   }
 }
 
-bool EmitterState::SetNullFormat(EMITTER_MANIP value, FmtScope::value scope) {
+bool EmitterState::SetNullFormat(EMITTER_MANIP value, FmtScope scope) {
   switch (value) {
     case LowerNull:
     case UpperNull:
@@ -313,7 +313,7 @@ bool EmitterState::SetNullFormat(EMITTER_MANIP value, FmtScope::value scope) {
   }
 }
 
-bool EmitterState::SetIntFormat(EMITTER_MANIP value, FmtScope::value scope) {
+bool EmitterState::SetIntFormat(EMITTER_MANIP value, FmtScope scope) {
   switch (value) {
     case Dec:
     case Hex:
@@ -325,7 +325,7 @@ bool EmitterState::SetIntFormat(EMITTER_MANIP value, FmtScope::value scope) {
   }
 }
 
-bool EmitterState::SetIndent(std::size_t value, FmtScope::value scope) {
+bool EmitterState::SetIndent(std::size_t value, FmtScope scope) {
   if (value <= 1)
     return false;
 
@@ -334,7 +334,7 @@ bool EmitterState::SetIndent(std::size_t value, FmtScope::value scope) {
 }
 
 bool EmitterState::SetPreCommentIndent(std::size_t value,
-                                       FmtScope::value scope) {
+                                       FmtScope scope) {
   if (value == 0)
     return false;
 
@@ -343,7 +343,7 @@ bool EmitterState::SetPreCommentIndent(std::size_t value,
 }
 
 bool EmitterState::SetPostCommentIndent(std::size_t value,
-                                        FmtScope::value scope) {
+                                        FmtScope scope) {
   if (value == 0)
     return false;
 
@@ -351,8 +351,8 @@ bool EmitterState::SetPostCommentIndent(std::size_t value,
   return true;
 }
 
-bool EmitterState::SetFlowType(GroupType::value groupType, EMITTER_MANIP value,
-                               FmtScope::value scope) {
+bool EmitterState::SetFlowType(GroupType groupType, EMITTER_MANIP value,
+                               FmtScope scope) {
   switch (value) {
     case Block:
     case Flow:
@@ -363,7 +363,7 @@ bool EmitterState::SetFlowType(GroupType::value groupType, EMITTER_MANIP value,
   }
 }
 
-EMITTER_MANIP EmitterState::GetFlowType(GroupType::value groupType) const {
+EMITTER_MANIP EmitterState::GetFlowType(GroupType groupType) const {
   // force flow style if we're currently in a flow
   if (CurGroupFlowType() == FlowType::Flow)
     return Flow;
@@ -372,7 +372,7 @@ EMITTER_MANIP EmitterState::GetFlowType(GroupType::value groupType) const {
   return (groupType == GroupType::Seq ? m_seqFmt.get() : m_mapFmt.get());
 }
 
-bool EmitterState::SetMapKeyFormat(EMITTER_MANIP value, FmtScope::value scope) {
+bool EmitterState::SetMapKeyFormat(EMITTER_MANIP value, FmtScope scope) {
   switch (value) {
     case Auto:
     case LongKey:
@@ -383,7 +383,7 @@ bool EmitterState::SetMapKeyFormat(EMITTER_MANIP value, FmtScope::value scope) {
   }
 }
 
-bool EmitterState::SetFloatPrecision(std::size_t value, FmtScope::value scope) {
+bool EmitterState::SetFloatPrecision(std::size_t value, FmtScope scope) {
   if (value > std::numeric_limits<float>::max_digits10)
     return false;
   _Set(m_floatPrecision, value, scope);
@@ -391,7 +391,7 @@ bool EmitterState::SetFloatPrecision(std::size_t value, FmtScope::value scope) {
 }
 
 bool EmitterState::SetDoublePrecision(std::size_t value,
-                                      FmtScope::value scope) {
+                                      FmtScope scope) {
   if (value > std::numeric_limits<double>::max_digits10)
     return false;
   _Set(m_doublePrecision, value, scope);
diff --git a/src/emitterstate.h b/src/emitterstate.h
index 8f379ca..243fab7 100644
--- a/src/emitterstate.h
+++ b/src/emitterstate.h
@@ -18,14 +18,16 @@
 #include <vector>
 
 namespace YAML {
-struct FmtScope {
-  enum value { Local, Global };
+enum class FmtScope {
+  Local, Global
 };
-struct GroupType {
-  enum value { NoType, Seq, Map };
+
+enum class GroupType {
+  NoType, Seq, Map
 };
-struct FlowType {
-  enum value { NoType, Flow, Block };
+
+enum class FlowType {
+  NoType, Flow, Block
 };
 
 class EmitterState {
@@ -51,14 +53,14 @@ class EmitterState {
   void StartedDoc();
   void EndedDoc();
   void StartedScalar();
-  void StartedGroup(GroupType::value type);
-  void EndedGroup(GroupType::value type);
+  void StartedGroup(GroupType type);
+  void EndedGroup(GroupType type);
 
-  EmitterNodeType::value NextGroupType(GroupType::value type) const;
+  EmitterNodeType::value NextGroupType(GroupType type) const;
   EmitterNodeType::value CurGroupNodeType() const;
 
-  GroupType::value CurGroupType() const;
-  FlowType::value CurGroupFlowType() const;
+  GroupType CurGroupType() const;
+  FlowType CurGroupFlowType() const;
   std::size_t CurGroupIndent() const;
   std::size_t CurGroupChildCount() const;
   bool CurGroupLongKey() const;
@@ -79,50 +81,50 @@ class EmitterState {
   // formatters
   void SetLocalValue(EMITTER_MANIP value);
 
-  bool SetOutputCharset(EMITTER_MANIP value, FmtScope::value scope);
+  bool SetOutputCharset(EMITTER_MANIP value, FmtScope scope);
   EMITTER_MANIP GetOutputCharset() const { return m_charset.get(); }
 
-  bool SetStringFormat(EMITTER_MANIP value, FmtScope::value scope);
+  bool SetStringFormat(EMITTER_MANIP value, FmtScope scope);
   EMITTER_MANIP GetStringFormat() const { return m_strFmt.get(); }
 
-  bool SetBoolFormat(EMITTER_MANIP value, FmtScope::value scope);
+  bool SetBoolFormat(EMITTER_MANIP value, FmtScope scope);
   EMITTER_MANIP GetBoolFormat() const { return m_boolFmt.get(); }
 
-  bool SetBoolLengthFormat(EMITTER_MANIP value, FmtScope::value scope);
+  bool SetBoolLengthFormat(EMITTER_MANIP value, FmtScope scope);
   EMITTER_MANIP GetBoolLengthFormat() const { return m_boolLengthFmt.get(); }
 
-  bool SetBoolCaseFormat(EMITTER_MANIP value, FmtScope::value scope);
+  bool SetBoolCaseFormat(EMITTER_MANIP value, FmtScope scope);
   EMITTER_MANIP GetBoolCaseFormat() const { return m_boolCaseFmt.get(); }
 
-  bool SetNullFormat(EMITTER_MANIP value, FmtScope::value scope);
+  bool SetNullFormat(EMITTER_MANIP value, FmtScope scope);
   EMITTER_MANIP GetNullFormat() const { return m_nullFmt.get(); }
 
-  bool SetIntFormat(EMITTER_MANIP value, FmtScope::value scope);
+  bool SetIntFormat(EMITTER_MANIP value, FmtScope scope);
   EMITTER_MANIP GetIntFormat() const { return m_intFmt.get(); }
 
-  bool SetIndent(std::size_t value, FmtScope::value scope);
+  bool SetIndent(std::size_t value, FmtScope scope);
   std::size_t GetIndent() const { return m_indent.get(); }
 
-  bool SetPreCommentIndent(std::size_t value, FmtScope::value scope);
+  bool SetPreCommentIndent(std::size_t value, FmtScope scope);
   std::size_t GetPreCommentIndent() const { return m_preCommentIndent.get(); }
-  bool SetPostCommentIndent(std::size_t value, FmtScope::value scope);
+  bool SetPostCommentIndent(std::size_t value, FmtScope scope);
   std::size_t GetPostCommentIndent() const { return m_postCommentIndent.get(); }
 
-  bool SetFlowType(GroupType::value groupType, EMITTER_MANIP value,
-                   FmtScope::value scope);
-  EMITTER_MANIP GetFlowType(GroupType::value groupType) const;
+  bool SetFlowType(GroupType groupType, EMITTER_MANIP value,
+                   FmtScope scope);
+  EMITTER_MANIP GetFlowType(GroupType groupType) const;
 
-  bool SetMapKeyFormat(EMITTER_MANIP value, FmtScope::value scope);
+  bool SetMapKeyFormat(EMITTER_MANIP value, FmtScope scope);
   EMITTER_MANIP GetMapKeyFormat() const { return m_mapKeyFmt.get(); }
 
-  bool SetFloatPrecision(std::size_t value, FmtScope::value scope);
+  bool SetFloatPrecision(std::size_t value, FmtScope scope);
   std::size_t GetFloatPrecision() const { return m_floatPrecision.get(); }
-  bool SetDoublePrecision(std::size_t value, FmtScope::value scope);
+  bool SetDoublePrecision(std::size_t value, FmtScope scope);
   std::size_t GetDoublePrecision() const { return m_doublePrecision.get(); }
 
  private:
   template <typename T>
-  void _Set(Setting<T>& fmt, T value, FmtScope::value scope);
+  void _Set(Setting<T>& fmt, T value, FmtScope scope);
 
   void StartedNode();
 
@@ -151,7 +153,7 @@ class EmitterState {
   SettingChanges m_globalModifiedSettings;
 
   struct Group {
-    explicit Group(GroupType::value type_)
+    explicit Group(GroupType type_)
         : type(type_),
           flowType{},
           indent(0),
@@ -159,8 +161,8 @@ class EmitterState {
           longKey(false),
           modifiedSettings{} {}
 
-    GroupType::value type;
-    FlowType::value flowType;
+    GroupType type;
+    FlowType flowType;
     std::size_t indent;
     std::size_t childCount;
     bool longKey;
@@ -196,7 +198,7 @@ class EmitterState {
 };
 
 template <typename T>
-void EmitterState::_Set(Setting<T>& fmt, T value, FmtScope::value scope) {
+void EmitterState::_Set(Setting<T>& fmt, T value, FmtScope scope) {
   switch (scope) {
     case FmtScope::Local:
       m_modifiedSettings.push(fmt.set(value));
diff --git a/src/emitterutils.cpp b/src/emitterutils.cpp
index 6cdf6de..adb0560 100644
--- a/src/emitterutils.cpp
+++ b/src/emitterutils.cpp
@@ -152,7 +152,7 @@ void WriteCodePoint(ostream_wrapper& out, int codePoint) {
   }
 }
 
-bool IsValidPlainScalar(const std::string& str, FlowType::value flowType,
+bool IsValidPlainScalar(const std::string& str, FlowType flowType,
                         bool allowOnlyAscii) {
   // check against null
   if (IsNullString(str)) {
@@ -206,7 +206,7 @@ bool IsValidSingleQuotedScalar(const std::string& str, bool escapeNonAscii) {
   });
 }
 
-bool IsValidLiteralScalar(const std::string& str, FlowType::value flowType,
+bool IsValidLiteralScalar(const std::string& str, FlowType flowType,
                           bool escapeNonAscii) {
   if (flowType == FlowType::Flow) {
     return false;
@@ -269,7 +269,7 @@ bool WriteAliasName(ostream_wrapper& out, const std::string& str) {
 
 StringFormat::value ComputeStringFormat(const std::string& str,
                                         EMITTER_MANIP strFormat,
-                                        FlowType::value flowType,
+                                        FlowType flowType,
                                         bool escapeNonAscii) {
   switch (strFormat) {
     case Auto:
diff --git a/src/emitterutils.h b/src/emitterutils.h
index 3a7d598..54fc12b 100644
--- a/src/emitterutils.h
+++ b/src/emitterutils.h
@@ -31,7 +31,7 @@ struct StringEscaping {
 namespace Utils {
 StringFormat::value ComputeStringFormat(const std::string& str,
                                         EMITTER_MANIP strFormat,
-                                        FlowType::value flowType,
+                                        FlowType flowType,
                                         bool escapeNonAscii);
 
 bool WriteSingleQuotedString(ostream_wrapper& out, const std::string& str);