public bool VisitFunctionDeclaration(FunctionDeclaration function)
{
string name = function.Name.Lexeme;
object value = new LoxFunction(function, _env);
_env.Define(name, value);
return(true);
}
public bool VisitReturnStatement(ReturnStatement returnStatement)
{
//TODO: the overhead of using an exception to hack stack unwinding makes me cringe :/
object value = returnStatement.Value?.Accept(this);
LoxFunction.Return(value);
return(true);
}
public object VisitFunction(Expr.Function expr)
{
// Capture the environment at declaration time.
string name = string.Format("<fun @{0}>", expr.Fun.Line);
var function = new LoxFunction(name, _environment, expr.Parameters, expr.Body);
return(function);
}
public Void Visit(Stmt.Function stmt)
{
var function = new LoxFunction(stmt, environment, false);
environment.Define(stmt.Name.Lexeme, function);
return(Void.Instance);
}
public Unit VisitFunction(Stmt.Function stmt)
{
// Capture the environment at declaration time.
string name = string.Format("<fun {0}>", stmt.Name.Lexeme);
var function = new LoxFunction(name, _environment, stmt.Parameters, stmt.Body);
_environment.Define(stmt.Name.Lexeme, function);
return(Unit.Default);
}
public override int Arity()
{
LoxFunction initializer = methods["init"];
if (initializer == null)
{
return(0);
}
return(initializer.Arity());
}
public override object Call(Interpreter interpreter, List <object> arguments)
{
LoxInstance instance = new LoxInstance(this);
LoxFunction initializer = methods["init"];
if (initializer != null)
{
initializer.Bind(instance).Call(interpreter, arguments);
}
return(instance);
}
object Expr.IVisitor <object> .VisitSuperExpr(Expr.Super expr)
{
int distance = locals[expr];
LoxClass superclass = (LoxClass)environment.GetAt(distance, "super");
LoxInstance obj = (LoxInstance)environment.GetAt(distance - 1, "this");
LoxFunction method = superclass.FindMethod(obj, expr.method.lexeme);
if (method == null)
{
throw new RuntimeError(expr.method, "Undefined property '" + expr.method.lexeme + "'.");
}
return(method);
}
public object Get(Token name)
{
if (fields.ContainsKey(name.lexeme))
{
return(fields[name.lexeme]);
}
LoxFunction method = klass.FindMethod(this, name.lexeme);
if (method != null)
{
return(method);
}
throw new RuntimeError(name, "Undefined property '" + name.lexeme + "'.");
}
public object VisitClassStmt(Stmt.Class stmt)
{
environment.Define(stmt.Name.Lexeme, null);
var methods = new Dictionary <string, LoxFunction>();
stmt.Methods.ForEach(m =>
{
var function = new LoxFunction(m, environment, m.name.Equals("init"));
methods.Add(m.name.Lexeme, function);
});
var klass = new LoxClass(stmt.Name.Lexeme, methods);
environment.Assign(stmt.Name, klass);
return(null);
}
object Stmt.IVisitor <object> .VisitClassStmt(Stmt.Class stmt)
{
object superclass = null;
if (stmt.superclass != null)
{
superclass = Evaluate(stmt.superclass);
if (!(superclass is LoxClass))
{
throw new RuntimeError(stmt.superclass.name, "Superclass must be a class.");
}
}
environment.Define(stmt.name.lexeme, null);
if (stmt.superclass != null)
{
environment = new Environment(environment);
environment.Define("super", superclass);
}
Dictionary <string, LoxFunction> methods = new Dictionary <string, LoxFunction>();
foreach (Stmt.Function method in stmt.methods)
{
LoxFunction function = new LoxFunction(method, environment, method.name.lexeme.Equals("init"));
methods[method.name.lexeme] = function;
}
LoxClass klass = new LoxClass(stmt.name.lexeme, (LoxClass)superclass, methods);
if (superclass != null)
{
environment = environment.enclosing;
}
environment.Assign(stmt.name, klass);
return(null);
}
public Void Visit(Stmt.Class stmt)
{
environment.Define(stmt.Name.Lexeme, null);
object superclass = null;
if (stmt.Superclass != null)
{
superclass = Evaluate(stmt.Superclass);
if (!(superclass is LoxClass))
{
throw new RuntimeErrorException(stmt.Superclass.Name, "Superclass must be a class");
}
environment = new Environment(environment);
environment.Define("super", superclass);
}
var methods = new Dictionary <string, LoxFunction>();
foreach (var method in stmt.Methods)
{
var function = new LoxFunction(method, environment, method.Name.Lexeme.Equals("this"));
methods[method.Name.Lexeme] = function;
}
var klass = new LoxClass(stmt.Name.Lexeme, (LoxClass)superclass, methods);
if (superclass != null)
{
environment = environment.Enclosing;
}
environment.Assign(stmt.Name, klass);
return(null);
}