private Stmt ClassDeclaration()
{
Token name = Consume(TokenType.IDENTIFIER, "Expect class name.");
Expr.Variable superclass = null;
if (Match(TokenType.LESS))
{
Consume(TokenType.IDENTIFIER, "Expect superclass name.");
superclass = new Expr.Variable(Previous());
}
Consume(TokenType.LEFT_BRACE, "Expect '{' before class body.");
List <Stmt.Function> methods = new List <Stmt.Function>();
while (!Check(TokenType.RIGHT_BRACE) && !IsAtEnd())
{
methods.Add(Function("method"));
}
Consume(TokenType.RIGHT_BRACE, "Expect '}' after class body.");
return(new Stmt.Class(name, superclass, methods));
}
public object VisitVariableExpr(Expr.Variable expr)
{
if (scopes.Any() && scopes.Peek()[expr.Name.Lexeme] == false)
{
Lox.Error(expr.Name, "Cannot read local variable in its own initializer.");
}
ResolveLocal(expr, expr.Name);
return(null);
}
object Expr.IVisitor <object> .VisitVariableExpr(Expr.Variable expr)
{
if (scopes.Count > 0 && scopes.Peek().TryGetValue(expr.name.lexeme, out bool value))
{
if (!value)
{
Lox.Error(expr.name, "Cannot read local variable in its own initializer.");
}
}
ResolveLocal(expr, expr.name);
return(null);
}
public Unit VisitVariable(Expr.Variable expr)
{
// Because we recurse into the initializer expression (while the scope has the variable)
// in 'NotReady'), we can use this to check that the initializer expression doesn't refer
// to this variable.
Resolution res;
if (_scopes.Count != 0 && _scopes.Peek().TryGetValue(expr.Name.Lexeme, out res) && res == Resolution.NotReady)
{
_errors.AddResolverError(expr.Name, "Cannot read local variable in its own initializer");
}
ResolveLocal(expr, expr.Name);
return(Unit.Default);
}
public Void Visit(Expr.Variable expr)
{
if (scopes.Any())
{
var scope = scopes.Peek();
var name = expr.Name.Lexeme;
if (scope.ContainsKey(name) && scope[name] == false)
{
Lox.Error(expr.Name, "Cannot read local variable in its own initializer.");
}
}
ResolveLocal(expr, expr.Name);
return(Void.Instance);
}
public object VisitVariableExpr(Expr.Variable expr)
{
return(LookUpVariable(expr.Name, expr));
}
public string VisitVariable(Expr.Variable expr)
{
return(expr.Name.Lexeme);
}
object Expr.IVisitor <object> .VisitVariableExpr(Expr.Variable expr)
{
return(LookUpVariable(expr.name, expr));
}
public Class(Token name, Expr.Variable superclass, List <Stmt.Function> methods)
{
this.name = name;
this.superclass = superclass;
this.methods = methods;
}
public string VisitVariableExpr(Expr.Variable expr)
{
return(parenthesize("VAR", expr));
}