public 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.");
}
}
int classIndex = environment.Define(null);
if (stmt.superclass != null)
{
environment = new Environment(enclosing: environment);
environment.Define(superclass);
}
Dictionary <string, LoxFunction> methods = new Dictionary <string, LoxFunction>();
foreach (Stmt.Function method in stmt.methods)
{
LoxFunction loxFunc = new LoxFunction(method, closure: environment, method.name.lexeme == "init");
methods.Add(method.name.lexeme, loxFunc);
}
Dictionary <string, LoxFunction> staticMethods = new Dictionary <string, LoxFunction>();
foreach (Stmt.Function method in stmt.staticMethods)
{
LoxFunction loxFunc = new LoxFunction(method, closure: environment, false);
staticMethods.Add(method.name.lexeme, loxFunc);
}
LoxClass loxClass = new LoxClass(stmt.name.lexeme, (LoxClass)superclass, staticMethods, methods);
if (stmt.superclass != null)
{
environment = environment.enclosing;
}
environment.Assign(classIndex, loxClass);
return(null);
}
public object visitClassStmt(Stmt.Class stmt)
{
ClassType enclosingClass = currentClass;
currentClass = ClassType.CLASS;
Declare(stmt.name);
Define(stmt.name);
MarkUnused(stmt.name);
if (stmt.superclass != null)
{
if (stmt.superclass.name.lexeme == stmt.name.lexeme)
{
Lox.ReportError(stmt.superclass.name, "Class cannot inherit from itself.");
}
else
{
currentClass = ClassType.SUBCLASS;
Resolve(stmt.superclass);
BeginScope();
Peek(scopes)["super"] = true;
Peek(varIndices)["super"] = GetNextIndex();
}
}
BeginScope();
// "this" is the only variable we declare at class scope. That means that when ResolveLocal()
// is called on "this" in the methods, the resolver will compute depth = 1, index = 0.
// In LoxFunction.Bind(), we create a new function with a closure whose only variable is "this" (at index 0)
// and since it's a closure, it has a depth of 1 from the function body.
Peek(scopes)["this"] = true;
Peek(varIndices)["this"] = GetNextIndex(); // TODO maybe change to 0
foreach (Stmt.Function method in stmt.staticMethods)
{
Declare(method.name);
Define(method.name);
ResolveFunction(method.parameters, method.body, FunctionType.STATIC);
}
foreach (Stmt.Function method in stmt.methods)
{
Declare(method.name);
Define(method.name);
FunctionType declaration = FunctionType.METHOD;
if (method.name.lexeme == "init")
{
declaration = FunctionType.INITIALIZER;
}
ResolveFunction(method.parameters, method.body, declaration);
}
EndScope();
if (stmt.superclass != null)
{
EndScope();
}
currentClass = enclosingClass;
return(null);
}