gmane.comp.lang.lua.general

Garbage collector behaviour changed from 5.1 to 5.2

Robert Norris — 2012-05-26T11:09:31

Hi all,

Pioneer[1] is a game written in C++ that uses Lua for its scripting.
We expose game objects to the Lua environment using "boxed pointers".
We upgraded Lua from 5.1.4 to 5.2.0 a couple of weeks ago and have
noticed substantial increases in memory usage since them, to the point
that one of our developers on a machine with not much memory now can't
play because the game causes his machine to swap to death.

Investigating has uncovered a few potential problems with the way our
Lua bindings are written which we intend to investigate - mostly that
we allocate more game objects than we probably should and we certainly
need to limit the amount of memory Lua can use. There is however a
definite change in the way the garbage collector behaves, which can be
demonstrated by the short program available here:

  http://pastebin.com/UAgtS3PX

As you can see, while the 5.1 collector would regularly clean up and
keep memory usage fairly flat, the 5.2 collector rarely runs and when
it does it does not clean up much.

Luarocks

Emeka — 2012-05-25T23:10:25

Hello All,

I got the below while trying  to use luarocks. Looks like it was checking
out Lua 5.1 while I have moved up to 5.2

rmicro< at >ubuntu:~/Downloads/luarocks-0.1$ luarocks install luasocket
Installing
http://luarocks.org/repositories/rocks/luasocket-2.0.2-5.src.rock...
Archive:
 /tmp/luarocks_luarocks-rock-luasocket-2.0.2-5-5764/luasocket-2.0.2-5.src.rock
  inflating: luasocket-2.0.2-5.rockspec
  inflating: luasocket-2.0.2.tar.gz
cd src; make all
make[1]: Entering directory
`/tmp/luarocks_luasocket-2.0.2-5-3165/luasocket-2.0.2/src'
gcc -O2 -DLUASOCKET_DEBUG -I/usr/include/lua5.1   -c -o luasocket.o
luasocket.c
gcc -O2 -DLUASOCKET_DEBUG -I/usr/include/lua5.1   -c -o timeout.o timeout.c
gcc -O2 -DLUASOCKET_DEBUG -I/usr/include/lua5.1   -c -o buffer.o buffer.c
gcc -O2 -DLUASOCKET_DEBUG -I/usr/include/lua5.1   -c -o io.o io.c
gcc -O2 -DLUASOCKET_DEBUG -I/usr/include/lua5.1   -c -o auxiliar.o
auxiliar.c
gcc -O2 -DLUASOCKET_DEBUG -I/usr/include/lua5.1   -c -o options.o options.c
gcc -O2 -DLUASOCKET_DEBUG -I/u

I don't understand this application of metamethod

Emeka — 2012-05-25T04:25:02

What is the essence of the below?

local Request = {}
Request.__index = Request

Regards, \Emeka

Not pretty clear

Emeka — 2012-05-25T04:18:37

Hello All,

I would need example,that is use case before the  below would sink.


*__mode* - Control weak references. A string value with one or both of the
characters 'k' and 'v' which specifies that the the *k*eys and/or *v*alues
in the table are weak references.


Regards, \Emeka

[ANNOUNCE] lua-users lottery drawing

John Belmonte — 2012-05-25T00:52:22

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

See <http://lua-users.org/wiki/LuaUsersLottery> for an opportunity to be
immortalized on the lua-users.org Acknowledgments page.

There went five years-- it's again time to pick members of the community
to pay the domain registration fee.  Two winners will be selected,
paying $25 USD each.  That amount will cover the domain name until
2017.  The last lottery, in 2007, had 27 participants-- that's the number
to beat  The drawing will be held at the start of Wednesday, May 30th
(midnight UTC).

Good luck (having an email titled "you won the lottery!" properly land in
your inbox)!

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)

iEYEARECAAYFAk++1yQACgkQ5Nfg6kxAQQqEEQCfTZ8bKgp9gCYS8hSF1fIgs0g2
nl4Ani3qbse+dHyfZ5+oiAs0FpeI4/RA
=A3rp
-----END PGP SIGNATURE-----

luasocket: Using http.request for POST request with BODY lead to timeout

Wilhelm Pflüger — 2012-05-24T21:15:07

I try to use socket.http to send a SOAP message with POST in the body of
http. 
See the following code:

local http = require("socket.http")

    body = [[<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <ViewLogStatus
xmlns="http://www.thermo.com/informatics/xmlns/limswebservice" />
  </soap:Body>
</soap:Envelope>]]

local r,c,h = http.request{
    url = "http://xx/LimsWebService/default.asmx?op=ViewLogStatus",
    sink = ltn12.sink.file(io.open("test.out", "w")),
    headers = {
      ["Content-Type"] = "text/xml; charset=utf-8",
      ["content-length"] = tostring(body:len()),

["SOAPAction"]="\"http://www.thermo.com/informatics/xmlns/limswebservice/ViewLogStatus\""
        ["Host"] = "xx",
        },
    body = ltn12.source.string(body),
    method = "POST"
}

This leads always to a timeout and using a wireshark i can see the ht

Upvalues when dump/load a function?

Tim Hill — 2012-05-24T17:14:45

Would anyone like to comment on the behavior of this code? It prints "local x" and "nil", which is probably correct, but odd. I understand that "load()" compiles code in a global context, but when I have the output of string.dump() its not really being compiled again, is it? It's just packaged VM bytecodes. Given that, what happens to the upvalues? The ref manual for 5.2 simply says "with new upvalues" when a dumped function is loaded, but makes no mention of what this means, and of course in the code sample there ARE no upvalues to bind to the function anyway.

x = "global x"

do
local x = "local x"
function foo() print(x) end
end

foo()
sf = string.dump(foo)
f2 = load(sf, "", "bt", _ENV)
f2()

Trouble with mailing list

Ignacio Burgueño — 2012-05-24T15:18:20

Excuse me if this is a problem on my end, but I recently noticed that
whenever I reply to a message on this list, the message gets delivered
correctly but shortly after that, I get a mail from
lua.to.typisch< at >xoxy.net with the subject "Undelivered Mail Returned to
Sender".

Part of the message follows:

~~~~~~~~~~~~~~~~~~~~
This is the mail system at host mx1.nonlin.de.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                  The mail system

<+public/amavis< at >nonlin.de>: host mx1.nonlin.de[/var/run/cyrus/socket/lmtp]
   said: 550-Mailbox unknown.  Either there is no mailbox associated with this
   550-name or you do not have authorization to see it. 550 5.1.1 User unknown
   (in reply to RCPT TO command)

Final-Recipient: rfc822; +public/amavis< at >nonlin.de
Ori

lua-openssl need help to fix a bug on OpenSUSE 12.1 and ArchLinux

zhiguo zhao — 2012-05-24T14:49:08

Hi  hello.

     I get some bug report for lua-openssl, I can't finger out the reason
of the bugs,
     Please give me some advice.

    Issue at
https://github.com/zhaozg/lua-openssl/issues/7#issuecomment-5894470
    Code at https://github.com/zhaozg/lua-openssl

    I test it on centos5/centos6 32 bits, Windows 32bits,  I works for me.
    But I don't  have a OpenSuse box,  I need someone's help.

    Here is a traceback,that make me trouble.

----------------------------------------------------------------------------------

$ lua a.lua
lua: malloc.c:3096: sYSMALLOc: Assertion (old*top == (((mbinptr) (((char *)
&((av)->bins[((1) - 1) * 2])) - __builtin_offsetof (struct malloc_chunk,
fd)))) && old_size == 0) || ((unsigned long) (old_size) >= (unsigned
long)((((*_builtin_offsetof (struct malloc_chunk, fd_nextsize))+((2 *
(sizeof(size_t))) - 1)) & ~((2 * (sizeof(size_t))) - 1))) &&
((old_top)->size & 0x1) && ((unsigned long)old_end & pagemask) == 0)'
failed.
Aborted (core dumped)


Stack trace:

#0 0xb754e8c

[ANN] lgi 0.6 Lua binding using gobject-introspection

Pavel Holejsovsky — 2012-05-24T14:33:12

Hello Lua hackers,

lgi 0.6 (alpha series) was released.  As usual, it is available either 
from its github homepage[1], [2], luarocks (by 'luarocks install lgi'), 
and newly it is also packaged in debian/unstable (lua-lgi and 
lua-lgi-dev packages).

lgi is gobject-introspection based dynamic Lua binding to GObject 
libraries. It allows using GObject-based libraries directly from Lua. 
If it sounds gibberish to you, ten simly said it allows easy usage of 
GTK+ and similar libraries from Lua.

The main improvement in this version is cairo drawing library support. 
With cairo support in place, lgi's support of GTK+ is now fairly complete.

Other than that, there were a few fixes mainly for supporting of some 
'exotic' architectures (s390x, mips).

Any comments or other feedback will be greatly appreciated, use github
issue tracker [3] for reporting bugs.

Happy hacking!
Pavel


[1] http://github.com/pavouk/lgi
[2] http://github.com/downloads/pavouk/lgi/lgi-0.6.tar.gz
[3] http://github.com/pavouk/lgi/issues

[ANN] Lua 5.2.1 (rc1) now available

Luiz Henrique de Figueiredo — 2012-05-23T17:09:38

Lua 5.2.1 (rc1) is now available at
http://www.lua.org/work/lua-5.2.1-rc1.tar.gz

MD51f0b1d1f184afec7d081909671cbf478  -
SHA16f12b8296962c20cc78d3d8e1f39417622017dc8  -

Lua 5.2.1 fixes all bugs listed in http://www.lua.org/bugs.html#5.2.0 .

Lua 5.2.1 also fixes several other minor glitches and includes a revised
reference manual.

The complete diffs from lua-5.2.0 to 5.2.1 are available at
http://www.lua.org/work/diffs-lua-5.2.0-lua-5.2.1-rc1.txt

We thank everyone for their feedback on Lua 5.2 till now.

All feedback welcome. Thanks.
--lhf

Wishlist for PiL 3rd ed.

sergei karhof — 2012-05-23T13:10:16

I don't know if Roberto accepts custom orders ;), but here are a
couple of things I would really like to see in the third edition of
PiL:

* a brief mention of the major Lua extensions, with their main
features. Since Lua does not come with a standard library of its own,
having a schematic table of the most popular extensions is essential
for the beginners.

* something about the use of Lua on portable devices (Android,
microcontrollers, etc)

By the way, is the book release still scheduled for August 2012?

Cheers

Sergei

Storing Lua code in a C library

Rena — 2012-05-23T00:18:30

I'm writing a Lua module in C, but I want to store some Lua code in it
as well to perform some initialization, and use lua_load() to run it
as needed. However, I'm wondering about the best way to store this
code.
If I store it compiled, it may not work, because the bytecode format
differs from one system to the next, correct?
But if I store it as text, it requires the compiler, which may not be
available e.g. in embedded systems?
How does lua_load() react if Lua was compiled without the ability to
compile code? Is there a reliable way to embed Lua code in a C
library?

luaffi vs luajit ffi

Cosmin Apreutesei — 2012-05-22T16:03:01

Hi,

I'm using luajit ffi for a month now. I found that it's not just a
library as it extends the language in some key semantics:

(1) values of different types can be compared (Lua can't do that);
this makes things easier most of the time, and a tricky sometimes[1]
(2) type(cdata) == "cdata" -- so now we have the 9th Lua type -- ok
you can overload type(), but maybe ffi.type() similar to io.type()
would have been better, dunno.

I don't think you can make luaffi a drop-in replacement for lj ffi
without patching Lua to address (1) am I right?

[1] for a null pointer a, `a == nil` is true but `not a` is false and
`a = a or default` is not the same for a null pointer a and for a nil
value a.

Another take on locals by default.

Pierre-Yves Gérardy — 2012-05-22T12:55:51

I just stumbled on LiveScript (http://gkz.github.com/LiveScript/), yet
another CoffeeScript fork.

The language has locals by default, and has an interesting solution to
the local/upvalue definition and assignment conundrum.

`a = 5` is always a local assignment. a is declared as local if it
wasn't already. To assingn to an upvalue, you use the := operator.
The language doesn't have globals. Transposed to Lua, this would be.

    make_incr = function()
      acc=0 --local, by default
      return function()
        acc = acc + 1
        -- a local acc shadows the upvalue.
        -- this always add 1 to nil, or 1 to 0,
        -- depending on when you decide to declare the local,
        -- before or after the evaluation of the right hand side.
        return acc
      end
    end

    incr= make_incr()
    incr() --> 1
    incr() --> 1


    -- This works as intended
    make_incr = function()
      acc=0 --local, by default
      return function()
         acc := acc + 1 -- upvalue assignment
         retu

[ANN] Lua Workshop 2012

Luiz Henrique de Figueiredo — 2012-05-21T17:05:17

We are pleased to announce that the Lua Workshop 2012 will be hosted
by Verisign and organized by John Rodriguez. The Workshop will take
place on Nov 29 and 30 at Verisign's headquartes in Reston, Virginia,
15 minutes from Dulles International Airport.

A weg page for the Workshop will be up soon at
http://www.lua.org/wshop12.html

As in previous workshops, the workshop is open to everyone interested in Lua.
We hope to see many of you there.

--lhf

writing the values in the variables of lua !!

Maha Akkari — 2012-05-21T13:27:45

I am integrating Network Simulator 3 and Lua.

I wrote a Mobile File in Lua script. that file will go on the network,
visit certain nodes and collect information from them.

The problem I am facing is that dont know how to keep the information that
was collected from the nodes,  i.e. I dont know how to save that
information I am getting in the variables of Luascript !!!

let me explain , for simplicity reasons, say my MobileAgent.lua script
initially  contains :

array1 ={"10.10.2.3", "10.10.4.3"}

array2={ ip1="10.2.3.4", ip2="10.3.2.4"}

function update_array1 (t)
  (some code )
end

function update_array2 (t)
  (some code )
end


So remember, my MobileAgent.lua will travel to some nodes on the network
and update the arrays.
say MobileAgent.lua has to visit node1 ,node2 and node3.

so first, the file arrives at node 1.
node1 calls the script and add the element "255.255.255.0" to both arrays.

What I want it for the MobileAgent.lua to look like this :

*array1 ={"10.10.2.3", "10.10.4.3" , "255.255.255.0"}*

Storing passwords

Paco Willers — 2012-05-21T13:04:02

Hi,

I would like to store passwords in my Lua 5.1 application. For example as
an MD5 hash. I managed to do that with  luacrypto. I wish to continue my
developing on a server which doesn't have the crypto C library installed
which luacrypto depends on, so I cannot use luacrypto here. Is it possible
to do hash encrypting in a Lua-only manner? On the Lua wiki I saw an
article: it is possible with Lua 5.2. Can I switch to Lua 5.2 and still use
Lua modules/libs that are written for Lua 5.1? (luasocket, coxpcall, copas)
Any tips are welcome.

Have a nice day, :-)
Paco

Maintainer sought for LuaPosix

Reuben Thomas — 2012-05-21T12:32:47

LuaPosix (https://github.com/rrthomas/luaposix) is, for those who don't
know, a binding of POSIX APIs for Lua.

It's been around since at least Lua 3.1 (1998), but for much of its life
has been unmaintained. I took it over a few years ago from Natanael Copa so
I could work on it for the Lua version of the GNU Zile editor. At that
time, there was very little development activity.

In the past few months I've had a great deal of interest, and many fixes
and additions to the library. Many thanks to the various contributors!
However, looking after the library and keeping its design and coding
coherent in the face of additions while allowing it to grow is not really
something that interests me, or to which I'm suited: I still have only the
one application that uses it (Zile) and I am not regularly using the
library apart from that.

Hence, I'd very much like to hand over to a new maintainer. Could anyone
interested please write to me off-list?

In the mean time, contributors (and users) should not worry: I don't

removing key from table

forume — 2012-05-21T08:59:25

I have some trouble with removing keys from tables.

t = {a = 10}

How can I remove these kind of table keys?

I tried many table.remove() variations of course but none worked.

Is it possible to remove this kind of key at all?

Help: Has someone knows how to replace lua_Number with a C++ class?

Xavier Wang — 2012-05-21T11:57:47

hi list :-)

I just have a idea that replace lua_Number as a GMP number or MAPM
number, is that possible? I mean, A lua with native big number
support?

regards,
Xaiver Wang.