Added scopes

headers/Environment.h

@@ -15,7 +15,19 @@ public:
 
     std::shared_ptr<Object> get(Token name);
 
+    sptr(Environment) enclosing;
+
+    Environment(){
+        enclosing = nullptr;
+    }
+
+    Environment(sptr(Environment) environment) : enclosing(environment)
+    {
+
+    }
 private:
     std::unordered_map<std::string, sptr(Object)> variables;
 
+
+
 };

headers/Interpreter.h

@@ -16,15 +16,22 @@ public:
     sptr(Object) visitVariableExpr(sptr(VarExpr) expression) override;
     sptr(Object) visitAssignExpr(sptr(AssignExpr) expression) override;
 
+    void visitBlockStmt(sptr(BlockStmt) statement) override;
     void visitExpressionStmt(sptr(ExpressionStmt) statement) override;
     void visitPrintStmt(sptr(PrintStmt) statement) override;
     void visitVarStmt(sptr(VarStmt) statement) override;
 
     void interpret(std::vector<sptr(Stmt)> statements);
 
+    Interpreter(){
+        environment = msptr(Environment)();
+    }
+
 private:
 
-    Environment environment;
+    sptr(Environment) environment;
+
+
 
     sptr(Object) evaluate(sptr(Expr) expr);
     bool isTruthy(sptr(Object) object);
@@ -35,4 +42,6 @@ private:
     bool isWholeNumer(double num);
 
     void execute(std::shared_ptr<Stmt> statement);
+
+    void executeBlock(std::vector<std::shared_ptr<Stmt>> statements, std::shared_ptr<Environment> env);
 };

headers/Lexer.h

@@ -63,7 +63,6 @@ struct Token
 {
     TokenType type;
     std::string lexeme;
-    //TODO Object literal;
     int line;
 };
 

headers/Parser.h

@@ -47,4 +47,6 @@ private:
     std::shared_ptr<Stmt> varDeclaration();
 
     std::shared_ptr<Expr> assignment();
+
+    std::vector<std::shared_ptr<Stmt>> block();
 };

headers/Statement.h

@@ -8,9 +8,11 @@
 struct ExpressionStmt;
 struct PrintStmt;
 struct VarStmt;
+struct BlockStmt;
 
 struct StmtVisitor
 {
+    virtual void visitBlockStmt(sptr(BlockStmt) stmt) = 0;
     virtual void visitExpressionStmt(sptr(ExpressionStmt) stmt) = 0;
     virtual void visitPrintStmt(sptr(PrintStmt) stmt) = 0;
     virtual void visitVarStmt(sptr(VarStmt) stmt) = 0;
@@ -23,6 +25,18 @@ struct Stmt
     virtual ~Stmt(){};
 };
 
+struct BlockStmt : Stmt, public std::enable_shared_from_this<BlockStmt>
+{
+    const std::vector<sptr(Stmt)> statements;
+    explicit BlockStmt(std::vector<sptr(Stmt)> statements) : statements(statements)
+    {
+    }
+    void accept(StmtVisitor* visitor) override
+    {
+        visitor->visitBlockStmt(shared_from_this());
+    }
+};
+
 struct ExpressionStmt : Stmt, public std::enable_shared_from_this<ExpressionStmt>
 {
     const sptr(Expr) expression;

headers/TypeWrapper.h

@@ -17,8 +17,7 @@ struct String : Object
     std::string value;
     explicit String(std::string str) : value(str) {}
     ~String(){
-        std::cout << value.size() << std::endl;
+
-        std::cout << "String being destroyed..." << std::endl;
     }
 };
 

source.bob

@@ -1 +1,5 @@
-10 10;
+var a = 1;
+{
+  var a = a + 2;
+  print a;
+}

source/Environment.cpp

@@ -13,6 +13,11 @@ sptr(Object) Environment::get(Token name)
         return variables[name.lexeme];
     }
 
+    if(enclosing != nullptr)
+    {
+        return enclosing->get(name);
+    }
+
     throw std::runtime_error("Undefined variable '" + name.lexeme + "'.");
 }
 
@@ -30,5 +35,11 @@ void Environment::assign(Token name, std::shared_ptr<Object> value) {
         return;
     }
 
+    if(enclosing != nullptr)
+    {
+        enclosing->assign(name, value);
+        return;
+    }
+
     throw std::runtime_error("Undefined variable '" + name.lexeme + "'.");
 }

source/Interpreter.cpp

@@ -148,15 +148,19 @@ sptr(Object) Interpreter::visitBinaryExpr(sptr(BinaryExpr) expression)
 
 sptr(Object) Interpreter::visitVariableExpr(sptr(VarExpr) expression)
 {
-    return environment.get(expression->name);
+    return environment->get(expression->name);
 }
 
 sptr(Object) Interpreter::visitAssignExpr(sptr(AssignExpr) expression) {
     sptr(Object) value = evaluate(expression->value);
-    environment.assign(expression->name, value);
+    environment->assign(expression->name, value);
     return value;
 }
 
+void Interpreter::visitBlockStmt(std::shared_ptr<BlockStmt> statement) {
+    executeBlock(statement->statements, msptr(Environment)(environment));
+}
+
 void Interpreter::visitExpressionStmt(sptr(ExpressionStmt) statement) {
     evaluate(statement->expression);
 }
@@ -176,7 +180,7 @@ void Interpreter::visitVarStmt(sptr(VarStmt) statement)
 
     //std::cout << "Visit var stmt: " << statement->name.lexeme << " set to: " << stringify(value) << std::endl;
 
-    environment.define(statement->name.lexeme, value);
+    environment->define(statement->name.lexeme, value);
 }
 
 void Interpreter::interpret(std::vector<sptr(Stmt)> statements) {
@@ -193,8 +197,29 @@ void Interpreter::interpret(std::vector<sptr(Stmt)> statements) {
 
 void Interpreter::execute(sptr(Stmt) statement)
 {
+    try {
         statement->accept(this);
     }
+    catch(std::exception &e)
+    {
+        std::cout << "ERROR OCCURRED: " << e.what() << std::endl;
+        return;
+    }
+}
+
+void Interpreter::executeBlock(std::vector<sptr(Stmt)> statements, sptr(Environment) env)
+{
+    sptr(Environment) previous = this->environment;
+    this->environment = env;
+
+    for(sptr(Stmt) s : statements)
+    {
+        execute(s);
+    }
+
+    this->environment = previous;
+
+}
 
 sptr(Object) Interpreter::evaluate(sptr(Expr) expr) {
     return expr->accept(this);

source/Parser.cpp

@@ -147,6 +147,7 @@ std::vector<sptr(Stmt)> Parser::parse() {
 sptr(Stmt) Parser::statement()
 {
     if(match({PRINT})) return printStatement();
+    if(match({OPEN_BRACE})) return msptr(BlockStmt)(block());
     return expressionStatement();
 }
 
@@ -164,6 +165,19 @@ sptr(Stmt) Parser::expressionStatement()
     return msptr(ExpressionStmt)(expr);
 }
 
+std::vector<sptr(Stmt)> Parser::block()
+{
+    std::vector<sptr(Stmt)> statements;
+
+    while(!check(CLOSE_BRACE) && !isAtEnd())
+    {
+        statements.push_back(declaration());
+    }
+
+    consume(CLOSE_BRACE, "Expected '}' after block.");
+    return statements;
+}
+
 sptr(Stmt) Parser::declaration()
 {
     try{

source/main.cpp

@@ -8,8 +8,8 @@
 int main(){
     Bob bobLang;
 
-    //bobLang.runFile("source.bob");
+    bobLang.runFile("source.bob");
-    bobLang.runPrompt();
+    //bobLang.runPrompt();
 
     return 0;
 }