Introduce expression visitor

1 files changed, 55 insertions, 1 deletions

diff --git a/JSImpl/src/Expression.h b/JSImpl/src/Expression.h
index 0c23c6a..1934afc 100644
--- a/JSImpl/src/Expression.h
+++ b/JSImpl/src/Expression.h
@@ -3,15 +3,54 @@
 #include "CommonTypes.h"
 #include "Lexer.h"
 
+class Expression;
+class BinaryExpression;
+class UnaryExpression;
+class LiteralExpression;
+class IdentifierExpression;
+class ListExpression;
+class VariableDefinitionExpression;
+class BlockStatement;
+class LabeledStatement;
+class IfStatement;
+class SwitchStatement;
+class WhileStatement;
+class ForStatement;
+class FunctionDeclaration;
+class TopStatements;
+class EmptyExpression;
+using ExpressionPtr = IPLSharedPtr<Expression>;
+
+class ExpressionVisitor
+{
+public:
+	~ExpressionVisitor(){}
+	virtual void Visit(BinaryExpression* e) = 0;
+	virtual void Visit(UnaryExpression* e) = 0;
+	virtual void Visit(LiteralExpression* e) = 0;
+	virtual void Visit(IdentifierExpression* e) = 0;
+	virtual void Visit(ListExpression* e) = 0;
+	virtual void Visit(VariableDefinitionExpression* e) = 0;
+	virtual void Visit(BlockStatement* e) = 0;
+	virtual void Visit(LabeledStatement* e) = 0;
+	virtual void Visit(IfStatement* e) = 0;
+	virtual void Visit(SwitchStatement* e) = 0;
+	virtual void Visit(WhileStatement* e) = 0;
+	virtual void Visit(ForStatement* e) = 0;
+	virtual void Visit(FunctionDeclaration* e) = 0;
+	virtual void Visit(TopStatements* e) = 0;
+	virtual void Visit(EmptyExpression* e) = 0;
+};
+
 class Expression : public IPLEnableShared<Expression>
 {
 
 	public:
 		virtual ~Expression() {}
 		virtual void Print(std::ostream& os) const {};
+		virtual void Accept(ExpressionVisitor& v) = 0;
 };
 
-using ExpressionPtr = IPLSharedPtr<Expression>;
 
 // binary:= expression operator expression
 class BinaryExpression : public Expression
@@ -20,6 +59,7 @@ public:
 	virtual ~BinaryExpression() {}
 	BinaryExpression(ExpressionPtr exprLeft, ExpressionPtr exprRight, TokenType op);
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 private:
 	IPLString GetOperatorTypeAsString() const;
 private:
@@ -36,6 +76,7 @@ public:
 	virtual ~UnaryExpression() {}
 	UnaryExpression(IPLSharedPtr<Expression> expr, TokenType op, bool suffix);
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 private:
 	IPLString GetOperatorTypeAsString() const;
 private:
@@ -62,6 +103,7 @@ public:
 	LiteralExpression(bool);
 	LiteralExpression(TokenType type);
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 private:
 	double m_NumValue;
 	IPLString m_StringValue;
@@ -76,6 +118,7 @@ public:
 	IdentifierExpression(IPLString& name);
 	virtual ~IdentifierExpression() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 protected:
 	IPLString m_Name;
 
@@ -88,6 +131,7 @@ public:
 	void Push(ExpressionPtr value) { m_Values.push_back(value); };
 	virtual ~ListExpression() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 protected:
 	IPLVector<ExpressionPtr> m_Values;
 };
@@ -98,6 +142,7 @@ public:
 	VariableDefinitionExpression(IPLString& name, ExpressionPtr value) : IdentifierExpression(name), m_Value(value){}
 	virtual ~VariableDefinitionExpression() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 protected:
 	ExpressionPtr m_Value;
 };
@@ -108,6 +153,7 @@ public:
 	BlockStatement() {};
 	virtual ~BlockStatement() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 private:
 };
 
@@ -117,6 +163,7 @@ public:
 	LabeledStatement(IPLString& identifier, ExpressionPtr statements);
 	virtual ~LabeledStatement() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 private:
 	IPLString m_Identifier;
 	ExpressionPtr m_Statement;
@@ -128,6 +175,7 @@ public:
 	IfStatement(ExpressionPtr cond, ExpressionPtr ifStatement, ExpressionPtr elseStatement);
 	virtual ~IfStatement() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 private:
 	ExpressionPtr m_Condition;
 	ExpressionPtr m_IfStatement;
@@ -145,6 +193,7 @@ public:
 	SwitchStatement(ExpressionPtr cond, IPLVector<Case>& cases, ExpressionPtr defaultCase);
 	virtual ~SwitchStatement() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 private:
 	ExpressionPtr m_Condition;
 	IPLVector<Case> m_Cases;
@@ -157,6 +206,7 @@ public:
 	WhileStatement(ExpressionPtr cond, ExpressionPtr body, bool doWhile);
 	virtual ~WhileStatement() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 private:
 	ExpressionPtr m_Condition;
 	ExpressionPtr m_Body;
@@ -169,6 +219,7 @@ public:
 	ForStatement(ExpressionPtr initialization, ExpressionPtr cond, ExpressionPtr iteration, ExpressionPtr body);
 	virtual ~ForStatement() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 private:
 	ExpressionPtr m_Initialization;
 	ExpressionPtr m_Condition;
@@ -182,6 +233,7 @@ public:
 	FunctionDeclaration(IPLString& functionName, IPLVector<IPLString>& argumentsIdentifiers, ExpressionPtr body);
 	virtual ~FunctionDeclaration() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 private:
 	IPLString m_Name;
 	IPLVector<IPLString> m_ArgumentsIdentifiers;
@@ -194,6 +246,7 @@ public:
 	TopStatements() {}
 	virtual ~TopStatements() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 };
 
 class EmptyExpression : public Expression
@@ -202,6 +255,7 @@ public:
 	EmptyExpression() {}
 	virtual ~EmptyExpression() {}
 	virtual void Print(std::ostream& os) const override;
+	virtual void Accept(ExpressionVisitor& v) override { v.Visit(this); }
 };
 
 inline ExpressionPtr CreateEmptyExpression() { return IPLMakeSharePtr<EmptyExpression>(); }