public override HeronValue Eval(VM vm)
{
HeronValue val = vm.Eval(rvalue);
if (lvalue is Name)
{
string name = (lvalue as Name).name;
if (vm.HasVar(name))
{
vm.SetVar(name, val);
return(val);
}
else if (vm.HasField(name))
{
vm.SetField(name, val);
return(val);
}
else
{
throw new Exception(name + " is not a member field or local variable that can be assigned to");
}
}
else if (lvalue is ChooseField)
{
ChooseField field = lvalue as ChooseField;
HeronValue self = vm.Eval(field.self);
self.SetField(field.name, val);
return(val);
}
else if (lvalue is ReadAt)
{
ReadAt ra = lvalue as ReadAt;
HeronValue self = vm.Eval(ra.self);
HeronValue index = vm.Eval(ra.index);
ListValue list = self as ListValue;
if (list != null)
{
list.SetAtIndex(index, val);
return(val);
}
ArrayValue array = self as ArrayValue;
if (array != null)
{
array.SetAtIndex(index, val);
return(val);
}
throw new Exception("Unimplemented");
}
else
{
throw new Exception("Cannot assign to expression " + lvalue.ToString());
}
}
