Re: table.clear

[Andrew Starks <andrew.starks@...>]

On Fri, Dec 13, 2013 at 2:22 PM, Luther <lutheroto@gmail.com> wrote:
> I did see that thread, but when Andrew says "When someone sets the list
> to `nil`, i need to clear it.", it sounds like this:
>
> local list = createListAndFillItWithStuff()
>
> -- This magically clears the table, not the variable.
> list = nil
>
> I don't see how else to interpret his question.


obj = MyObj()

obj.list_of_stuff = Something_that_puts_bunches_of_objects_in_here()

---
Now, the act of adding stuff to this list is caught by a setter, which
iterates the list and does some object related maintenance, for
example, mapping video IO ports to logical outputs (probably not
helpful context, but it's the best I have)

Later, if I'm resetting this list:

obj.list_of_stuff = nil
---
I don't want that table to ever be *gone*, so I have a setter method
for `list_of_stuff` that stops this from resulting in its
nilification. Instead, clears the list and then some...

In a couple of cases, clearing any item in the list has consequences
for the object, so, I keep the actual list in a shadow table.

So would `table.clear` work on the shadow table? Does it work only on
things that are found in pairs? Does it work on anything it gets its
hands on, using lua_next?

If a user calls table.clear, and nothing happens, that's not _bad_. If
I could *define* what happened when it was called on a table, say in
"__clear", then I would use it in more often and I wouldn't need to
care/worry about the fact that it wouldn't work as expected / (as I
wanted) in certain table confabulations (shadow tables, etc).