vcmi: use std::variant

client/CPlayerInterface.cpp

@@ -1915,7 +1915,7 @@ void CPlayerInterface::requestReturningToMainMenu(bool won)
 
 void CPlayerInterface::askToAssembleArtifact(const ArtifactLocation &al)
 {
-	auto hero = boost::apply_visitor(HeroObjectRetriever(), al.artHolder);
+	auto hero = std::visit(HeroObjectRetriever(), al.artHolder);
 	if(hero)
 	{
 		auto art = hero->getArt(al.slot);
@@ -1932,14 +1932,14 @@ void CPlayerInterface::askToAssembleArtifact(const ArtifactLocation &al)
 void CPlayerInterface::artifactPut(const ArtifactLocation &al)
 {
 	EVENT_HANDLER_CALLED_BY_CLIENT;
-	auto hero = boost::apply_visitor(HeroObjectRetriever(), al.artHolder);
+	auto hero = std::visit(HeroObjectRetriever(), al.artHolder);
 	updateInfo(hero);
 }
 
 void CPlayerInterface::artifactRemoved(const ArtifactLocation &al)
 {
 	EVENT_HANDLER_CALLED_BY_CLIENT;
-	auto hero = boost::apply_visitor(HeroObjectRetriever(), al.artHolder);
+	auto hero = std::visit(HeroObjectRetriever(), al.artHolder);
 	updateInfo(hero);
 	for(auto isa : GH.listInt)
 	{
@@ -1954,7 +1954,7 @@ void CPlayerInterface::artifactRemoved(const ArtifactLocation &al)
 void CPlayerInterface::artifactMoved(const ArtifactLocation &src, const ArtifactLocation &dst)
 {
 	EVENT_HANDLER_CALLED_BY_CLIENT;
-	auto hero = boost::apply_visitor(HeroObjectRetriever(), dst.artHolder);
+	auto hero = std::visit(HeroObjectRetriever(), dst.artHolder);
 	updateInfo(hero);
 
 	bool redraw = true;
@@ -1983,7 +1983,7 @@ void CPlayerInterface::bulkArtMovementStart(size_t numOfArts)
 void CPlayerInterface::artifactAssembled(const ArtifactLocation &al)
 {
 	EVENT_HANDLER_CALLED_BY_CLIENT;
-	auto hero = boost::apply_visitor(HeroObjectRetriever(), al.artHolder);
+	auto hero = std::visit(HeroObjectRetriever(), al.artHolder);
 	updateInfo(hero);
 	for(auto isa : GH.listInt)
 	{
@@ -1996,7 +1996,7 @@ void CPlayerInterface::artifactAssembled(const ArtifactLocation &al)
 void CPlayerInterface::artifactDisassembled(const ArtifactLocation &al)
 {
 	EVENT_HANDLER_CALLED_BY_CLIENT;
-	auto hero = boost::apply_visitor(HeroObjectRetriever(), al.artHolder);
+	auto hero = std::visit(HeroObjectRetriever(), al.artHolder);
 	updateInfo(hero);
 	for(auto isa : GH.listInt)
 	{

lib/LogicalExpression.h

@@ -21,7 +21,7 @@ namespace LogicalExpressionDetail
 	class ExpressionBase
 	{
 	public:
-		/// Possible logical operations, mostly needed to create different types for boost::variant
+		/// Possible logical operations, mostly needed to create different types for std::variant
 		enum EOperations
 		{
 			ANY_OF,
@@ -37,7 +37,7 @@ namespace LogicalExpressionDetail
 		typedef ContainedClass Value;
 
 		/// Variant that contains all possible elements from logical expression
-		typedef boost::variant<
+		typedef std::variant<
 			OperatorAll,
 			OperatorAny,
 			OperatorNone,
@@ -81,7 +81,7 @@ namespace LogicalExpressionDetail
 		{
 			return boost::range::count_if(element, [&](const typename Base::Variant & expr)
 			{
-				return boost::apply_visitor(*this, expr);
+				return std::visit(*this, expr);
 			});
 		}
 	public:
@@ -131,7 +131,7 @@ namespace LogicalExpressionDetail
 		{
 			return boost::range::count_if(element, [&](const typename Base::Variant & expr)
 			{
-				return boost::apply_visitor(*satisfiabilityVisitor, expr);
+				return std::visit(*satisfiabilityVisitor, expr);
 			});
 		}
 
@@ -139,7 +139,7 @@ namespace LogicalExpressionDetail
 		{
 			return boost::range::count_if(element, [&](const typename Base::Variant & expr)
 			{
-				return boost::apply_visitor(*falsifiabilityVisitor, expr);
+				return std::visit(*falsifiabilityVisitor, expr);
 			});
 		}
 
@@ -254,7 +254,7 @@ namespace LogicalExpressionDetail
 			if (!classTest(element))
 			{
 				for (auto & elem : element.expressions)
-					boost::range::copy(boost::apply_visitor(*this, elem), std::back_inserter(ret));
+					boost::range::copy(std::visit(*this, elem), std::back_inserter(ret));
 			}
 			return ret;
 		}
@@ -265,7 +265,7 @@ namespace LogicalExpressionDetail
 			if (!classTest(element))
 			{
 				for (auto & elem : element.expressions)
-					boost::range::copy(boost::apply_visitor(*this, elem), std::back_inserter(ret));
+					boost::range::copy(std::visit(*this, elem), std::back_inserter(ret));
 			}
 			return ret;
 		}
@@ -306,7 +306,7 @@ namespace LogicalExpressionDetail
 		typename Base::Variant operator()(Type element) const
 		{
 			for (auto & entry : element.expressions)
-				entry = boost::apply_visitor(*this, entry);
+				entry = std::visit(*this, entry);
 			return element;
 		}
 	};
@@ -330,15 +330,15 @@ namespace LogicalExpressionDetail
 
 			for (auto & entryRO : element.expressions)
 			{
-				auto entry = boost::apply_visitor(*this, entryRO);
+				auto entry = std::visit(*this, entryRO);
 
 				try
 				{
 					// copy entries from child of this type
-					auto sublist = boost::get<Type>(entry).expressions;
+					auto sublist = std::get<Type>(entry).expressions;
 					std::move(sublist.begin(), sublist.end(), std::back_inserter(ret.expressions));
 				}
-				catch (boost::bad_get &)
+				catch (std::bad_variant_access &)
 				{
 					// different type (e.g. allOf vs oneOf) just copy
 					ret.expressions.push_back(entry);
@@ -410,7 +410,7 @@ namespace LogicalExpressionDetail
 			ret.Vector().resize(1);
 			ret.Vector().back().String() = name;
 			for (auto & expr : element)
-				ret.Vector().push_back(boost::apply_visitor(*this, expr));
+				ret.Vector().push_back(std::visit(*this, expr));
 			return ret;
 		}
 	public:
@@ -465,7 +465,7 @@ namespace LogicalExpressionDetail
 			std::string ret;
 			prefix.push_back('\t');
 			for (auto & expr : element)
-				ret += prefix + boost::apply_visitor(*this, expr) + "\n";
+				ret += prefix + std::visit(*this, expr) + "\n";
 			prefix.pop_back();
 			return ret;
 		}
@@ -552,14 +552,14 @@ public:
 	Variant morph(std::function<Variant(const Value &)> morpher) const
 	{
 		LogicalExpressionDetail::ForEachVisitor<Value> visitor(morpher);
-		return boost::apply_visitor(visitor, data);
+		return std::visit(visitor, data);
 	}
 
 	/// Minimizes expression, removing any redundant elements
 	void minimize()
 	{
 		LogicalExpressionDetail::MinimizingVisitor<Value> visitor;
-		data = boost::apply_visitor(visitor, data);
+		data = std::visit(visitor, data);
 	}
 
 	/// calculates if expression evaluates to "true".
@@ -567,7 +567,7 @@ public:
 	bool test(std::function<bool(const Value &)> toBool) const
 	{
 		LogicalExpressionDetail::TestVisitor<Value> testVisitor(toBool);
-		return boost::apply_visitor(testVisitor, data);
+		return std::visit(testVisitor, data);
 	}
 
 	/// calculates if expression can evaluate to "true".
@@ -579,7 +579,7 @@ public:
 		satisfiabilityVisitor.setFalsifiabilityVisitor(&falsifiabilityVisitor);
 		falsifiabilityVisitor.setSatisfiabilityVisitor(&satisfiabilityVisitor);
 
-		return boost::apply_visitor(satisfiabilityVisitor, data);
+		return std::visit(satisfiabilityVisitor, data);
 	}
 
 	/// calculates if expression can evaluate to "false".
@@ -591,14 +591,14 @@ public:
 		satisfiabilityVisitor.setFalsifiabilityVisitor(&falsifiabilityVisitor);
 		falsifiabilityVisitor.setFalsifiabilityVisitor(&satisfiabilityVisitor);
 
-		return boost::apply_visitor(falsifiabilityVisitor, data);
+		return std::visit(falsifiabilityVisitor, data);
 	}
 
 	/// generates list of candidates that can be fulfilled by caller (like AI)
 	std::vector<Value> getFulfillmentCandidates(std::function<bool(const Value &)> toBool) const
 	{
 		LogicalExpressionDetail::CandidatesVisitor<Value> candidateVisitor(toBool);
-		return boost::apply_visitor(candidateVisitor, data);
+		return std::visit(candidateVisitor, data);
 	}
 
 	/// Converts expression in human-readable form
@@ -607,18 +607,18 @@ public:
 	std::string toString(std::function<std::string(const Value &)> toStr) const
 	{
 		LogicalExpressionDetail::Printer<Value> printVisitor(toStr);
-		return boost::apply_visitor(printVisitor, data);
+		return std::visit(printVisitor, data);
 	}
 	std::string toString(std::function<std::string(const Value &)> toStr, std::function<bool(const Value &)> toBool) const
 	{
 		LogicalExpressionDetail::Printer<Value> printVisitor(toStr, toBool);
-		return boost::apply_visitor(printVisitor, data);
+		return std::visit(printVisitor, data);
 	}
 
 	JsonNode toJson(std::function<JsonNode(const Value &)> toJson) const
 	{
 		LogicalExpressionDetail::Writer<Value> writeVisitor(toJson);
-		return boost::apply_visitor(writeVisitor, data);
+		return std::visit(writeVisitor, data);
 	}
 
 	template <typename Handler>

lib/NetPacksBase.h

@@ -233,7 +233,7 @@ struct Component
 	}
 };
 
-using TArtHolder = boost::variant<ConstTransitivePtr<CGHeroInstance>, ConstTransitivePtr<CStackInstance>>;
+using TArtHolder = std::variant<ConstTransitivePtr<CGHeroInstance>, ConstTransitivePtr<CStackInstance>>;
 
 struct ArtifactLocation
 {
@@ -259,9 +259,9 @@ struct ArtifactLocation
 	template <typename T>
 	bool isHolder(const T *t) const
 	{
-		if(auto ptrToT = boost::get<ConstTransitivePtr<T> >(&artHolder))
+		if(auto ptrToT = std::get<ConstTransitivePtr<T>>(artHolder))
 		{
-			return ptrToT->get() == t;
+			return ptrToT == t;
 		}
 		return false;
 	}

lib/NetPacksLib.cpp

@@ -1563,7 +1563,7 @@ void ArtifactLocation::removeArtifact()
 
 const CArmedInstance * ArtifactLocation::relatedObj() const
 {
-	return boost::apply_visitor(ObjectRetriever(), artHolder);
+	return std::visit(ObjectRetriever(), artHolder);
 }
 
 PlayerColor ArtifactLocation::owningPlayer() const
@@ -1574,12 +1574,12 @@ PlayerColor ArtifactLocation::owningPlayer() const
 
 CArtifactSet *ArtifactLocation::getHolderArtSet()
 {
-	return boost::apply_visitor(GetBase<CArtifactSet>(), artHolder);
+	return std::visit(GetBase<CArtifactSet>(), artHolder);
 }
 
 CBonusSystemNode *ArtifactLocation::getHolderNode()
 {
-	return boost::apply_visitor(GetBase<CBonusSystemNode>(), artHolder);
+	return std::visit(GetBase<CBonusSystemNode>(), artHolder);
 }
 
 const CArtifactInstance *ArtifactLocation::getArt() const
@@ -2533,12 +2533,12 @@ const CArtifactInstance * ArtSlotInfo::getArt() const
 
 CArtifactSet * BulkMoveArtifacts::getSrcHolderArtSet()
 {
-	return boost::apply_visitor(GetBase<CArtifactSet>(), srcArtHolder);
+	return std::visit(GetBase<CArtifactSet>(), srcArtHolder);
 }
 
 CArtifactSet * BulkMoveArtifacts::getDstHolderArtSet()
 {
-	return boost::apply_visitor(GetBase<CArtifactSet>(), dstArtHolder);
+	return std::visit(GetBase<CArtifactSet>(), dstArtHolder);
 }
 
 VCMI_LIB_NAMESPACE_END

lib/serializer/BinaryDeserializer.h

@@ -9,6 +9,7 @@
  */
 #pragma once
 
+#include <boost/mpl/vector.hpp>
 #include <boost/mpl/for_each.hpp>
 
 #include "CTypeList.h"
@@ -43,10 +44,21 @@ class DLL_LINKAGE BinaryDeserializer : public CLoaderBase
 		Source & source;
 		std::vector<std::function<Variant()>> funcs;
 
+		template <class V>
+		struct mpl_types_impl;
+
+		template <class... Ts>
+		struct mpl_types_impl<std::variant<Ts...>> {
+			using type = boost::mpl::vector<Ts...>;
+		};
+
+		template <class V>
+		using mpl_types = typename mpl_types_impl<V>::type;
+
 		VariantLoaderHelper(Source & source):
 			source(source)
 		{
-			boost::mpl::for_each<typename Variant::types>(std::ref(*this));
+			boost::mpl::for_each<mpl_types<Variant>>(std::ref(*this));
 		}
 
 		template<typename Type>
@@ -495,9 +507,9 @@ public:
 	}
 
 	template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
-	void load(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> &data)
+	void load(std::variant<BOOST_VARIANT_ENUM_PARAMS(T)> &data)
 	{
-		typedef boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> TVariant;
+		typedef std::variant<BOOST_VARIANT_ENUM_PARAMS(T)> TVariant;
 
 		VariantLoaderHelper<TVariant, BinaryDeserializer> loader(*this);
 

lib/serializer/BinarySerializer.h

@@ -331,13 +331,13 @@ public:
 		}
 	}
 	template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
-	void save(const boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> &data)
+	void save(const std::variant<BOOST_VARIANT_ENUM_PARAMS(T)> &data)
 	{
-		si32 which = data.which();
+		si32 which = data.index();
 		save(which);
 
 		VariantVisitorSaver<BinarySerializer> visitor(*this);
-		boost::apply_visitor(visitor, data);
+		std::visit(visitor, data);
 	}
 	template <typename T>
 	void save(const boost::optional<T> &data)

scripting/erm/ERMInterpreter.cpp

@@ -185,7 +185,7 @@ namespace ERMConverter
 
 		Variable operator()(const TVarExp & var) const
 		{
-			return boost::apply_visitor(LVL2IexpToVar(), var);
+			return std::visit(LVL2IexpToVar(), var);
 		}
 	};
 
@@ -196,8 +196,8 @@ namespace ERMConverter
 
 		std::string operator()(const TComparison & cmp) const
 		{
-			Variable lhs = boost::apply_visitor(LVL1IexpToVar(), cmp.lhs);
+			Variable lhs = std::visit(LVL1IexpToVar(), cmp.lhs);
-			Variable rhs = boost::apply_visitor(LVL1IexpToVar(), cmp.rhs);
+			Variable rhs = std::visit(LVL1IexpToVar(), cmp.rhs);
 
 			auto sign = CMP_OPERATION.find(cmp.compSign);
 			if(sign == std::end(CMP_OPERATION))
@@ -314,7 +314,7 @@ namespace ERMConverter
 			ret.isInput = false;
 			ret.semi = true;
 			ret.semiCmpSign = cmp.compSign;
-			ret.name = (boost::apply_visitor(LVL1IexpToVar(), cmp.rhs)).str();
+			ret.name = (std::visit(LVL1IexpToVar(), cmp.rhs)).str();
 			return ret;
 		}
 
@@ -327,7 +327,7 @@ namespace ERMConverter
 		{
 			ParamIO ret;
 			ret.isInput = true;
-			ret.name = (boost::apply_visitor(LVL1IexpToVar(), cmp)).str();;
+			ret.name = (std::visit(LVL1IexpToVar(), cmp)).str();;
 			return ret;
 		}
 
@@ -336,7 +336,7 @@ namespace ERMConverter
 			ParamIO ret;
 			ret.isInput = false;
 
-			ret.name = (boost::apply_visitor(LVL2IexpToVar(), cmp.var)).str();
+			ret.name = (std::visit(LVL2IexpToVar(), cmp.var)).str();
 			return ret;
 		}
 
@@ -399,7 +399,7 @@ namespace ERMConverter
 			if(trig.params.is_initialized())
 			{
 				for(auto & p : trig.params.get())
-					optionParams.push_back(boost::apply_visitor(BodyOption(), p));
+					optionParams.push_back(std::visit(BodyOption(), p));
 			}
 
 			int idx = 1;
@@ -511,7 +511,7 @@ namespace ERMConverter
 
 		FU(std::ostream * out_, const ERM::TIexp & tid)
 			: Receiver(out_),
-			v(boost::apply_visitor(LVL1IexpToVar(), tid))
+			v(std::visit(LVL1IexpToVar(), tid))
 		{
 		}
 
@@ -558,7 +558,7 @@ namespace ERMConverter
 
 		MC(std::ostream * out_, const ERM::TIexp & tid)
 			: Receiver(out_),
-			v(boost::apply_visitor(LVL1IexpToVar(), tid))
+			v(std::visit(LVL1IexpToVar(), tid))
 		{
 		}
 
@@ -580,7 +580,7 @@ namespace ERMConverter
 					{
 						for(auto & p : option.params.get())
 						{
-							std::string macroName = boost::apply_visitor(MC_S(), p);
+							std::string macroName = std::visit(MC_S(), p);
 
 							boost::format callFormat;
 
@@ -616,7 +616,7 @@ namespace ERMConverter
 
 		std::string operator()(const TIexp & cmp) const override
 		{
-			auto v = boost::apply_visitor(LVL1IexpToVar(), cmp);
+			auto v = std::visit(LVL1IexpToVar(), cmp);
 			return v.str();
 		}
 		std::string operator()(const TStringConstant & cmp) const override
@@ -636,7 +636,7 @@ namespace ERMConverter
 
 		std::string operator()(const TIexp & cmp) const override
 		{
-			Variable p = boost::apply_visitor(LVL1IexpToVar(), cmp);
+			Variable p = std::visit(LVL1IexpToVar(), cmp);
 
 			if(p.index <= 0)
 				throw EScriptExecError("VR:H requires flag index");
@@ -661,7 +661,7 @@ namespace ERMConverter
 
 		std::string operator()(const TIexp & cmp) const override
 		{
-			Variable p = boost::apply_visitor(LVL1IexpToVar(), cmp);
+			Variable p = std::visit(LVL1IexpToVar(), cmp);
 
 			return p.str();
 		}
@@ -673,7 +673,7 @@ namespace ERMConverter
 
 		VR(std::ostream * out_, const ERM::TIexp & tid)
 			: Receiver(out_),
-			v(boost::apply_visitor(LVL1IexpToVar(), tid))
+			v(std::visit(LVL1IexpToVar(), tid))
 		{
 		}
 
@@ -681,7 +681,7 @@ namespace ERMConverter
 
 		void operator()(const TVRLogic & trig) const override
 		{
-			Variable rhs = boost::apply_visitor(LVL1IexpToVar(), trig.var);
+			Variable rhs = std::visit(LVL1IexpToVar(), trig.var);
 
 			std::string opcode;
 
@@ -705,7 +705,7 @@ namespace ERMConverter
 
 		void operator()(const TVRArithmetic & trig) const override
 		{
-			Variable rhs = boost::apply_visitor(LVL1IexpToVar(), trig.rhs);
+			Variable rhs = std::visit(LVL1IexpToVar(), trig.rhs);
 
 			std::string opcode;
 
@@ -746,7 +746,7 @@ namespace ERMConverter
 					if(trig.params.is_initialized())
 					{
 						for(auto & p : trig.params.get())
-							optionParams.push_back(boost::apply_visitor(BodyOption(), p));
+							optionParams.push_back(std::visit(BodyOption(), p));
 					}
 
 					auto index = v.index;
@@ -768,7 +768,7 @@ namespace ERMConverter
 					if(!trig.params.is_initialized() || trig.params.get().size() != 1)
 						throw EScriptExecError("VR:H option takes exactly 1 parameter!");
 
-					std::string opt = boost::apply_visitor(VR_H(), trig.params.get()[0]);
+					std::string opt = std::visit(VR_H(), trig.params.get()[0]);
 					boost::format fmt("ERM.VR(%s):H(%s)");
 					fmt % v.str() % opt;
 					putLine(fmt.str());
@@ -779,7 +779,7 @@ namespace ERMConverter
 					if(!trig.params.is_initialized() || trig.params.get().size() != 1)
 						throw EScriptExecError("VR:H/U need 1 parameter!");
 
-					std::string opt = boost::apply_visitor(VR_S(), trig.params.get()[0]);
+					std::string opt = std::visit(VR_S(), trig.params.get()[0]);
 					boost::format fmt("ERM.VR(%s):%c(%s)");
 					fmt % v.str() % (trig.optionCode) % opt;
 					putLine(fmt.str());
@@ -790,7 +790,7 @@ namespace ERMConverter
 					if(!trig.params.is_initialized() || trig.params.get().size() < 2)
 						throw EScriptExecError("VR:M needs at least 2 parameters!");
 
-					std::string opt = boost::apply_visitor(VR_X(), trig.params.get()[0]);
+					std::string opt = std::visit(VR_X(), trig.params.get()[0]);
 					int paramIndex = 1;
 
 					if(opt == "3")
@@ -801,7 +801,7 @@ namespace ERMConverter
 					}
 					else
 					{
-						auto target = boost::apply_visitor(VR_X(), trig.params.get()[paramIndex++]);
+						auto target = std::visit(VR_X(), trig.params.get()[paramIndex++]);
 
 						boost::format fmt("%s = ERM.VR(%s):M%s(");
 						fmt % target % v.str() % opt;
@@ -810,7 +810,7 @@ namespace ERMConverter
 					
 					for(int i = paramIndex; i < trig.params.get().size(); i++)
 					{
-						opt = boost::apply_visitor(VR_X(), trig.params.get()[i]);
+						opt = std::visit(VR_X(), trig.params.get()[i]);
 						if(i > paramIndex) put(",");
 						put(opt);
 					}
@@ -823,7 +823,7 @@ namespace ERMConverter
 					if(!trig.params.is_initialized() || trig.params.get().size() != 1)
 						throw EScriptExecError("VR:X option takes exactly 1 parameter!");
 
-					std::string opt = boost::apply_visitor(VR_X(), trig.params.get()[0]);
+					std::string opt = std::visit(VR_X(), trig.params.get()[0]);
 
 					boost::format fmt("%s = bit.bxor(%s, %s)");
 					fmt % v.str() % v.str() % opt;putLine(fmt.str());
@@ -840,7 +840,7 @@ namespace ERMConverter
 					if(!trig.params.is_initialized() || trig.params.get().size() != 1)
 						throw EScriptExecError("VR:S option takes exactly 1 parameter!");
 
-					std::string opt = boost::apply_visitor(VR_S(), trig.params.get()[0]);
+					std::string opt = std::visit(VR_S(), trig.params.get()[0]);
 					put(v.str());
 					put(" = ");
 					put(opt);
@@ -858,7 +858,7 @@ namespace ERMConverter
 					if(!trig.params.is_initialized() || trig.params.get().size() != 1)
 						throw EScriptExecError("VR:V option takes exactly 1 parameter!");
 
-					std::string opt = boost::apply_visitor(VR_X(), trig.params.get()[0]);
+					std::string opt = std::visit(VR_X(), trig.params.get()[0]);
 					boost::format fmt("%s = tostring(%s)");
 					fmt % v.str() % opt;
 					putLine(fmt.str());
@@ -886,7 +886,7 @@ namespace ERMConverter
 				const ERM::Tbody & bo = body.get();
 				for(int g=0; g<bo.size(); ++g)
 				{
-					boost::apply_visitor(visitor, bo[g]);
+					std::visit(visitor, bo[g]);
 				}
 			}
 		}
@@ -915,11 +915,11 @@ namespace ERMConverter
 
 				if(argc > 0)
 				{
-					std::string loopCounter = (boost::apply_visitor(LVL1IexpToVar(), tid.at(0))).str();
+					std::string loopCounter = (std::visit(LVL1IexpToVar(), tid.at(0))).str();
 
-					std::string startVal = argc > 1 ? (boost::apply_visitor(LVL1IexpToVar(), tid.at(1))).str() : loopCounter;
+					std::string startVal = argc > 1 ? (std::visit(LVL1IexpToVar(), tid.at(1))).str() : loopCounter;
-					std::string stopVal = argc > 2 ? (boost::apply_visitor(LVL1IexpToVar(), tid.at(2))).str() : loopCounter;
+					std::string stopVal = argc > 2 ? (std::visit(LVL1IexpToVar(), tid.at(2))).str() : loopCounter;
-					std::string increment = argc > 3 ? (boost::apply_visitor(LVL1IexpToVar(), tid.at(3))).str() : "1";
+					std::string increment = argc > 3 ? (std::visit(LVL1IexpToVar(), tid.at(3))).str() : "1";
 
 					boost::format fmt("for __iter = %s, %s, %s do");
 
@@ -962,7 +962,7 @@ namespace ERMConverter
 				{
 					for(const auto & id : identifier.get())
 					{
-						Variable v = boost::apply_visitor(LVL1IexpToVar(), id);
+						Variable v = std::visit(LVL1IexpToVar(), id);
 
 						if(v.isSpecial())
 							throw ELineProblem("Special variable syntax ('d') is not allowed in receiver identifier");
@@ -1018,7 +1018,7 @@ namespace ERMConverter
 
 		void convertConditionInner(const Tcondition & cond, char op) const
 		{
-			std::string lhs = boost::apply_visitor(Condition(), cond.cond);
+			std::string lhs = std::visit(Condition(), cond.cond);
 
 			if(cond.ctype != '/')
 				op = cond.ctype;
@@ -1057,7 +1057,7 @@ namespace ERMConverter
 		void convertCondition(const Tcondition & cond) const
 		{
 			//&c1/c2/c3|c4/c5/c6 -> (c1  & c2  & c3)  | c4  |  c5  | c6
-			std::string lhs = boost::apply_visitor(Condition(), cond.cond);
+			std::string lhs = std::visit(Condition(), cond.cond);
 			put("if ");
 			put(lhs);
 
@@ -1143,7 +1143,7 @@ namespace ERMConverter
 
 		void operator()(const Tcommand & cmd) const
 		{
-			boost::apply_visitor(ERMExp(out), cmd.cmd);
+			std::visit(ERMExp(out), cmd.cmd);
 		}
 		void operator()(const std::string & comment) const
 		{
@@ -1196,7 +1196,7 @@ namespace ERMConverter
 		void operator()(TLiteral const & opt) const
 		{
 			TLiteralEval tmp;
-			(*out) << boost::apply_visitor(tmp, opt);
+			(*out) << std::visit(tmp, opt);
 		}
 		void operator()(ERM::Tcommand const & opt) const
 		{
@@ -1204,7 +1204,7 @@ namespace ERMConverter
 			//TODO: can we evaluate to smth more useful?
 			//???
 			throw EVermScriptExecError("Using ERM options in VERM expression is not (yet) allowed");
-//			boost::apply_visitor(ERMExp(out), opt.cmd);
+//			std::visit(ERMExp(out), opt.cmd);
 		}
 	};
 
@@ -1216,7 +1216,7 @@ namespace ERMConverter
 
 		for(VOption & op : tmpn.children)
 		{
-			boost::apply_visitor(VOptionEval(out), op);
+			std::visit(VOptionEval(out), op);
 			(*out) << ",";
 		}
 		(*out) << "}";
@@ -1242,7 +1242,7 @@ namespace ERMConverter
 		}
 		void operator()(TERMline const & cmd) const
 		{
-			boost::apply_visitor(Command(out), cmd);
+			std::visit(Command(out), cmd);
 		}
 	};
 
@@ -1257,7 +1257,7 @@ namespace ERMConverter
 		{
 			ERM::TLine & line = owner->retrieveLine(lp);
 
-			boost::apply_visitor(lineConverter, line);
+			std::visit(lineConverter, line);
 		}
 
 		out << "end" << std::endl;
@@ -1285,7 +1285,7 @@ namespace ERMConverter
 			if(tid.empty())
 				throw EInterpreterError("Function must have identifier");
 
-			Variable v = boost::apply_visitor(LVL1IexpToVar(), tid[0]);
+			Variable v = std::visit(LVL1IexpToVar(), tid[0]);
 
 			if(v.isSpecial())
 				throw ELineProblem("Special variable syntax ('d') is not allowed in function definition");
@@ -1304,7 +1304,7 @@ namespace ERMConverter
 				if(owner->isATrigger(curLine))
 					break;
 
-				boost::apply_visitor(lineConverter, curLine);
+				std::visit(lineConverter, curLine);
 			}
 
 			out << "end," << std::endl;
@@ -1332,7 +1332,7 @@ namespace ERMConverter
 			{
 				for(const auto & id : trig.identifier.get())
 				{
-					Variable v = boost::apply_visitor(LVL1IexpToVar(), id);
+					Variable v = std::visit(LVL1IexpToVar(), id);
 
 					if(v.isSpecial())
 						throw ELineProblem("Special variable syntax ('d') is not allowed in trigger definition");
@@ -1358,7 +1358,7 @@ namespace ERMConverter
 				if(owner->isATrigger(curLine))
 					break;
 
-				boost::apply_visitor(lineConverter, curLine);
+				std::visit(lineConverter, curLine);
 			}
 
 			out << "end," << std::endl;
@@ -1383,14 +1383,14 @@ struct ScriptScanner : boost::static_visitor<>
 	{
 		if(cmd.which() == 0) //TCommand
 		{
-			Tcommand tcmd = boost::get<Tcommand>(cmd);
+			Tcommand tcmd = std::get<Tcommand>(cmd);
 			switch (tcmd.cmd.which())
 			{
 			case 0: //trigger
 				{
 					Trigger trig;
 					trig.line = lp;
-					interpreter->triggers[ TriggerType(boost::get<ERM::Ttrigger>(tcmd.cmd).name) ].push_back(trig);
+					interpreter->triggers[ TriggerType(std::get<ERM::Ttrigger>(tcmd.cmd).name) ].push_back(trig);
 				}
 				break;
 			case 1: //instruction
@@ -1402,7 +1402,7 @@ struct ScriptScanner : boost::static_visitor<>
 				{
 					Trigger trig;
 					trig.line = lp;
-					interpreter->postTriggers[ TriggerType(boost::get<ERM::TPostTrigger>(tcmd.cmd).name) ].push_back(trig);
+					interpreter->postTriggers[ TriggerType(std::get<ERM::TPostTrigger>(tcmd.cmd).name) ].push_back(trig);
 				}
 				break;
 			default:
@@ -1431,7 +1431,7 @@ bool ERMInterpreter::isATrigger( const ERM::TLine & line )
 	{
 	case 0: //v-exp
 		{
-			TVExp vexp = boost::get<TVExp>(line);
+			TVExp vexp = std::get<TVExp>(line);
 			if(vexp.children.empty())
 				return false;
 
@@ -1441,7 +1441,7 @@ bool ERMInterpreter::isATrigger( const ERM::TLine & line )
 				return false;
 				break;
 			case TCMD:
-				return isCMDATrigger( boost::get<ERM::Tcommand>(vexp.children[0]) );
+				return isCMDATrigger( std::get<ERM::Tcommand>(vexp.children[0]) );
 				break;
 			default:
 				return false;
@@ -1451,11 +1451,11 @@ bool ERMInterpreter::isATrigger( const ERM::TLine & line )
 		break;
 	case 1: //erm
 		{
-			TERMline ermline = boost::get<TERMline>(line);
+			TERMline ermline = std::get<TERMline>(line);
 			switch(ermline.which())
 			{
 			case 0: //tcmd
-				return isCMDATrigger( boost::get<ERM::Tcommand>(ermline) );
+				return isCMDATrigger( std::get<ERM::Tcommand>(ermline) );
 				break;
 			default:
 				return false;
@@ -1500,17 +1500,17 @@ ERM::TTriggerBase & ERMInterpreter::retrieveTrigger(ERM::TLine & line)
 {
 	if(line.which() == 1)
 	{
-		ERM::TERMline &tl = boost::get<ERM::TERMline>(line);
+		ERM::TERMline &tl = std::get<ERM::TERMline>(line);
 		if(tl.which() == 0)
 		{
-			ERM::Tcommand &tcm = boost::get<ERM::Tcommand>(tl);
+			ERM::Tcommand &tcm = std::get<ERM::Tcommand>(tl);
 			if(tcm.cmd.which() == 0)
 			{
-				return boost::get<ERM::Ttrigger>(tcm.cmd);
+				return std::get<ERM::Ttrigger>(tcm.cmd);
 			}
 			else if(tcm.cmd.which() == 3)
 			{
-				return boost::get<ERM::TPostTrigger>(tcm.cmd);
+				return std::get<ERM::TPostTrigger>(tcm.cmd);
 			}
 			throw ELineProblem("Given line is not a trigger!");
 		}
@@ -1533,7 +1533,7 @@ std::string ERMInterpreter::loadScript(const std::string & name, const std::stri
 		scripts[LinePointer(static_cast<int>(buf.size()), g, buf[g].realLineNum)] = buf[g].tl;
 
 	for(auto p : scripts)
-		boost::apply_visitor(ScriptScanner(this, p.first), p.second);
+		std::visit(ScriptScanner(this, p.first), p.second);
 
 	std::stringstream out;
 
@@ -1575,7 +1575,7 @@ namespace VERMInterpreter
 {
 	VOption convertToVOption(const ERM::TVOption & tvo)
 	{
-		return boost::apply_visitor(OptionConverterVisitor(), tvo);
+		return std::visit(OptionConverterVisitor(), tvo);
 	}
 
 	VNode::VNode( const ERM::TVExp & exp )

scripting/erm/ERMInterpreter.h

@@ -213,15 +213,15 @@ namespace VERMInterpreter
 	{};
 
 
-	typedef boost::variant<char, double, int, std::string> TLiteral;
+	typedef std::variant<char, double, int, std::string> TLiteral;
 
-	typedef boost::variant<VNIL, boost::recursive_wrapper<VNode>, VSymbol, TLiteral, ERM::Tcommand> VOption; //options in v-expression, VNIl should be the default
+	typedef std::variant<VNIL, boost::recursive_wrapper<VNode>, VSymbol, TLiteral, ERM::Tcommand> VOption; //options in v-expression, VNIl should be the default
 
 	template<typename T, typename SecType>
 	T& getAs(SecType & opt)
 	{
 		if(opt.type() == typeid(T))
-			return boost::get<T>(opt);
+			return std::get<T>(opt);
 		else
 			throw EVermScriptExecError("Wrong type!");
 	}

scripting/erm/ERMParser.cpp

@@ -28,7 +28,7 @@ namespace phoenix = boost::phoenix;
 //Greenspun's Tenth Rule of Programming:
 //Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified,
 //bug-ridden, slow implementation of half of Common Lisp.
-//actually these macros help in dealing with boost::variant
+//actually these macros help in dealing with std::variant
 
 
 CERMPreprocessor::CERMPreprocessor(const std::string & source)

scripting/erm/ERMParser.h

@@ -80,7 +80,7 @@ namespace ERM
 		Tval val;
 	};
 
-	typedef boost::variant<TVarExpNotMacro, TMacroUsage> TVarExp;
+	typedef std::variant<TVarExpNotMacro, TMacroUsage> TVarExp;
 
 	//write-only variable expression
 	struct TVarpExp
@@ -89,7 +89,7 @@ namespace ERM
 	};
 
 	//i-expression (identifier expression) - an integral constant, variable symbol or array symbol
-	typedef boost::variant<TVarExp, int> TIexp;
+	typedef std::variant<TVarExp, int> TIexp;
 
 	struct TArithmeticOp
 	{
@@ -127,7 +127,7 @@ namespace ERM
 		TStringConstant string;
 	};
 
-	typedef boost::variant<TVarConcatString, TStringConstant, TCurriedString, TSemiCompare, TMacroDef, TIexp, TVarpExp> TBodyOptionItem;
+	typedef std::variant<TVarConcatString, TStringConstant, TCurriedString, TSemiCompare, TMacroDef, TIexp, TVarpExp> TBodyOptionItem;
 
 	typedef std::vector<TBodyOptionItem> TNormalBodyOptionList;
 
@@ -136,9 +136,9 @@ namespace ERM
 		char optionCode;
 		boost::optional<TNormalBodyOptionList> params;
 	};
-	typedef boost::variant<TVRLogic, TVRArithmetic, TNormalBodyOption> TBodyOption;
+	typedef std::variant<TVRLogic, TVRArithmetic, TNormalBodyOption> TBodyOption;
 
-//	typedef boost::variant<TIexp, TArithmeticOp > TIdentifierInternal;
+//	typedef std::variant<TIexp, TArithmeticOp > TIdentifierInternal;
 	typedef std::vector< TIexp > Tidentifier;
 
 	struct TComparison
@@ -157,7 +157,7 @@ namespace ERM
 
 	struct Tcondition
 	{
-		typedef boost::variant<
+		typedef std::variant<
 			TComparison,
 			int>
 			Tcond; //comparison or condition flag
@@ -196,7 +196,7 @@ namespace ERM
 	//moreover, I encountered a quite serious bug in boost: http://boost.2283326.n4.nabble.com/container-hpp-111-error-C2039-value-type-is-not-a-member-of-td3352328.html
 	//not sure how serious it is...
 
-	//typedef boost::variant<char, TStringConstant, TMacroUsage, TMacroDef> bodyItem;
+	//typedef std::variant<char, TStringConstant, TMacroUsage, TMacroDef> bodyItem;
 	typedef std::vector<TBodyOption> Tbody;
 
 	struct Tinstruction
@@ -217,7 +217,7 @@ namespace ERM
 
 	struct Tcommand
 	{
-		typedef	boost::variant<
+		typedef	std::variant<
 			Ttrigger,
 			Tinstruction,
 			Treceiver,
@@ -231,7 +231,7 @@ namespace ERM
 	//vector expression
 
 
-	typedef boost::variant<Tcommand, std::string, boost::spirit::unused_type> TERMline;
+	typedef std::variant<Tcommand, std::string, boost::spirit::unused_type> TERMline;
 
 	typedef std::string TVModifier; //'`', ',', ',@', '#''
 
@@ -245,7 +245,7 @@ namespace ERM
 
 	enum EVOtions{VEXP, SYMBOL, CHAR, DOUBLE, INT, TCMD, STRINGC};
 	struct TVExp;
-	typedef boost::variant<boost::recursive_wrapper<TVExp>, TSymbol, char, double, int, Tcommand, TStringConstant > TVOption; //options in v-expression
+	typedef std::variant<boost::recursive_wrapper<TVExp>, TSymbol, char, double, int, Tcommand, TStringConstant > TVOption; //options in v-expression
 	//v-expression
 	struct TVExp
 	{
@@ -254,7 +254,7 @@ namespace ERM
 	};
 
 	//script line
-	typedef boost::variant<TVExp, TERMline> TLine;
+	typedef std::variant<TVExp, TERMline> TLine;
 
 	template <typename T> struct ERM_grammar;
 }

server/CGameHandler.cpp

@@ -662,7 +662,7 @@ void CGameHandler::endBattleConfirm(const BattleInfo * battleInfo)
 
 		if (finishingBattle->loserHero)
 		{
-			//TODO: wrap it into a function, somehow (boost::variant -_-)
+			//TODO: wrap it into a function, somehow (std::variant -_-)
 			auto artifactsWorn = finishingBattle->loserHero->artifactsWorn;
 			for (auto artSlot : artifactsWorn)
 			{
@@ -3930,11 +3930,11 @@ bool CGameHandler::moveArtifact(const ArtifactLocation &al1, const ArtifactLocat
 
 		try
 		{
-			auto hero = boost::get<ConstTransitivePtr<CGHeroInstance>>(dst.artHolder);
+			auto hero = std::get<ConstTransitivePtr<CGHeroInstance>>(dst.artHolder);
 			if(ArtifactUtils::checkSpellbookIsNeeded(hero, srcArtifact->artType->getId(), dst.slot))
 				giveHeroNewArtifact(hero, VLC->arth->objects[ArtifactID::SPELLBOOK], ArtifactPosition::SPELLBOOK);
 		}
-		catch(const boost::bad_get &)
+		catch(const std::bad_variant_access &)
 		{
 			// object other than hero received an art - ignore
 		}

server/CQuery.cpp

@@ -360,11 +360,11 @@ bool CGarrisonDialogQuery::blocksPack(const CPack * pack) const
 
 	if(auto arts = dynamic_ptr_cast<ExchangeArtifacts>(pack))
 	{
-		if(auto id1 = boost::apply_visitor(GetEngagedHeroIds(), arts->src.artHolder))
+		if(auto id1 = std::visit(GetEngagedHeroIds(), arts->src.artHolder))
 			if(!vstd::contains(ourIds, *id1))
 				return true;
 
-		if(auto id2 = boost::apply_visitor(GetEngagedHeroIds(), arts->dst.artHolder))
+		if(auto id2 = std::visit(GetEngagedHeroIds(), arts->dst.artHolder))
 			if(!vstd::contains(ourIds, *id2))
 				return true;
 		return false;
@@ -377,7 +377,7 @@ bool CGarrisonDialogQuery::blocksPack(const CPack * pack) const
 
 	if(auto art = dynamic_ptr_cast<EraseArtifactByClient>(pack))
 	{
-		if (auto id = boost::apply_visitor(GetEngagedHeroIds(), art->al.artHolder))
+		if (auto id = std::visit(GetEngagedHeroIds(), art->al.artHolder))
 			return !vstd::contains(ourIds, *id);
 	}