Re: orphaned data in lua?

[Spencer Parkin <spencertparkin@...>]

I suppose that some sort of graph traversal algorithm could be run in the background that traverses the graph formed by references and then identify that way portions of the graph that are orphaned by not touching any variable that is being kept by the user...loosely speaking...something like that, I suppose.

On Tue, Apr 29, 2014 at 11:10 PM, Spencer Parkin <spencertparkin@gmail.com> wrote:

Thanks for the replies.  I'm curious...  how does the algorithm work?  How can Lua determine what does and doesn't need to be collected if it doesn't keep a reference count on an object?

For example, it's clear that, after the code I had shown earlier is run, that tables A and B are in their own little reference group, but then the same can be said of the table "mytableC = {}" right after it is created.  It's in its own little reference group, yet it shouldn't be garbage collected.

I should probably buy the book.  I'm starting to vaguely recall the idea of...

mytableD = {}

mytableD.refD = mytableD

mytableD = nil

...in reading the book.  Or look at the book online...

On Tue, Apr 29, 2014 at 10:57 PM, Andrew Starks <andrew.starks@trms.com> wrote:

On Tuesday, April 29, 2014, Spencer Parkin <spencertparkin@gmail.com> wrote:

Consider the following...

mytablaA = {}
mytableB = {}
mytableA.refB = mytableB
mytableB.refA = mytableA

mytableA = nil
mytableB = nil

There is no longer a reference to either table, yet they reference one another, so the tables are still around, right?  If so, will these tables never get garbage collected?

Lua does not use a reference counter for its GC and is able to avoid these issues. Since there is no path to these tables, they'll be collected.