public object visitFunctionStmt(Stmt.Function stmt)
{
LoxFunction function = new LoxFunction(function: stmt, closure: environment, false);
environment.Define(function);
return(null);
}
public LoxClass(string name, LoxClass superclass, Dictionary <string, LoxFunction> staticMethods, Dictionary <string, LoxFunction> methods)
{
this.name = name;
this.superclass = superclass;
this.staticMethods = staticMethods;
this.methods = methods;
initializer = FindMethod("init");
}
public object visitSuperExpr(Expr.Super expr)
{
var exprLocationData = locals[expr];
LoxClass superclass = (LoxClass)environment.GetAt(exprLocationData.depth, exprLocationData.index);
// We know "this" is one environment removed from "super" because of the way we set the environments up
// in visitClassStmt. Hacky fix but it works. We also know its index is 0 because "this" is the only variable
// in its environment.
LoxInstance instance = (LoxInstance)environment.GetAt(exprLocationData.depth - 1, 0);
LoxFunction method = superclass.FindMethod(expr.method.lexeme);
if (method == null)
{
throw new RuntimeError(expr.method, "Undefined superclass property '" + expr.method.lexeme + "'.");
}
return(method.Bind(instance));
}
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 Get(Token name)
{
// Fields shadow properties
if (fields.TryGetValue(name.lexeme, out object value))
{
return(value);
}
// Property
LoxFunction method = loxClass.FindMethod(name.lexeme);
if (method != null)
{
return(method.Bind(this));
}
throw new RuntimeError(name, "Undefined property '" + name.data + "'.");
}