public override MetaObject BindGetMember(GetMemberBinder binder)
{
ContractUtils.RequiresNotNull(binder, "binder");
ExpandoClass klass = Value.Class;
int index = klass.GetValueIndex(binder.Name, binder.IgnoreCase);
string methodName = binder.IgnoreCase ? "ExpandoGetValueIgnoreCase" : "ExpandoGetValue";
Expression target;
if (index == -1)
{
// the key does not exist, report a MissingMemberException
target = Expression.Convert(
Expression.Throw(
Expression.New(
typeof(MissingMemberException).GetConstructor(new Type[] { typeof(string) }),
Expression.Constant(binder.Name)
)
),
typeof(object)
);
}
else
{
target = Expression.Call(
typeof(RuntimeOps).GetMethod(methodName),
GetLimitedSelf(),
Expression.Constant(klass),
Expression.Constant(index)
);
}
// add the dynamic test for the target
return(new MetaObject(
AddDynamicTestAndDefer(
binder,
new MetaObject[] { this },
klass,
null,
target
),
GetRestrictions()
));
}
/// <summary>
/// Gets the class and the index associated with the given name. Does not update the expando object. Instead
/// this returns both the original and desired new class. A rule is created which includes the test for the
/// original class, the promotion to the new class, and the set/delete based on the class post-promotion.
/// </summary>
private ExpandoClass GetClassEnsureIndex(string name, bool ignoreCase, out ExpandoClass klass, out int index)
{
ExpandoClass originalClass = Value.Class;
index = originalClass.GetValueIndex(name, ignoreCase);
if (index == -1)
{
// go ahead and find a new class now...
ExpandoClass newClass = originalClass.FindNewClass(name, ignoreCase);
klass = newClass;
index = newClass.GetValueIndex(name, ignoreCase);
Debug.Assert(index != -1);
return(originalClass);
}
else
{
klass = originalClass;
return(null);
}
}