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**Psyke Phaeton** · 03-06-2009, 07:59 PM

I have noticed a divergence with OpenSim LSL and SecondLife LSL.

Code:

default
{
    state_entry()
    {
        list llist = ["a","b"];
        llist = (llist=[]) + llist + ["c"];
        llSay(0, llDumpList2String(llist,"|"));
    }
}

was one way to conserve memory in SL when adding more data to something large.

In SL llist will become ["a","b","c"];

However is OpenSim XEngine (at least) llist will become ["c"]

Is this a bug, or should we stop using OpenSim for SL development due to divergence in how things work?

However..

Code:

default
{
    state_entry()
    {
        list llist = ["a","b"];
        llist += (llist=[]) + ["c"];
        llSay(0, llDumpList2String(llist,"|"));
    }
}

..works the same in both SL and OpenSim.

OpenSim warning:
"Warning: Multiple assignments to 'list' at line 5 column 19; results may differ between LSL and OSSL."

Kristian · 03-06-2009, 08:48 PM

Any divergence in the scripting lanuage should be considered a bug, I would think.

Beezle Warburton · 03-06-2009, 10:01 PM

Quote:

Originally Posted by Psyke Phaeton

I have noticed a divergence with OpenSim LSL and SecondLife LSL.

Code:

default
{
    state_entry()
    {
        list llist = ["a","b"];
        llist = (llist=[]) + llist + ["c"];
        llSay(0, llDumpList2String(llist,"|"));
    }
}

was one way to conserve memory in SL when adding more data to something large.

In SL llist will become ["a","b","c"];

However is OpenSim XEngine (at least) llist will become ["c"]

Is this a bug, or should we stop using OpenSim for SL development due to divergence in how things work?

However..

Code:

default
{
    state_entry()
    {
        list llist = ["a","b"];
        llist += (llist=[]) + ["c"];
        llSay(0, llDumpList2String(llist,"|"));
    }
}

..works the same in both SL and OpenSim.

OpenSim warning:
"Warning: Multiple assignments to 'list' at line 5 column 19; results may differ between LSL and OSSL."

Many moons ago, this would've been the sort of thing I would've avoided in programming because of uncertain order-of-operation.

llist = (llist=[]) + llist + ["c"];

Besides that some languages any "assignment" value would return TRUE

(a=1) = TRUE

So you could possibly get a 'type mismatch' as you are trying to add a logical value to a list without typecasting it first.

At best you would assume that it would do correct order-of-operation:

The problem being you don't know whether it'll get the value of llist rewritten to [] before it adds it in a second time.

Mutters about memory recall/write vs. processing cyles and timings and stuff I used to know a lot more about.

LSL is goofy.

It's not so much a divergence in processing as to how a different platform copes with a logically 'questionable' script line.

**Psyke Phaeton** · 03-06-2009, 10:21 PM

Even so it begs the bigger question. Can OpenSim in the future be used to develop for SecondLife? Or will the differences become too much.

Whilst I agree that having to do the above to save memory is stupid, it is extremely useful when limited to 64kb. It would become tedious if, to develop code on OpenSim, we had to edit it after transfering to SL.

I hope they keep 100% "goofy" LSL compatibility whilst also developing all the other compatibilities.

Beezle Warburton · 03-06-2009, 10:34 PM

It's tricky to ensure compatibility for things that are basically hacks that work on sluggish processors.

**Adam Zaius** · 03-07-2009, 12:19 AM

I know the list hack has been a point of contention - since to support the SL order of operations there requires rewriting parts of the LSL Lexer/Parser we use. There's a bug on the mantis about it.

0003187: popular list memory saving hack does not work in LSL - Mantis

**Psyke Phaeton** · 03-07-2009, 12:58 AM

I guess I had better update my OpenSim

ZATZAi · 03-07-2009, 04:55 AM

That's a rather lively mantis report...

03-06-2009, 07:59 PM	#1 (permalink)
Psyke Phaeton Senior Member SLU Supporter Running 'round in Circle's Join Date: Sep 2007 Location: Australia Posts: 6,949 My Mood: SLShopper Ads: 1 SL Join Date: 12-Oct-2003 Business: Psyke's Defence Systems Blog Entries: 3	OpenSim compatibility: A place to develop for SecondLife, or not? I have noticed a divergence with OpenSim LSL and SecondLife LSL. Code: default { state_entry() { list llist = ["a","b"]; llist = (llist=[]) + llist + ["c"]; llSay(0, llDumpList2String(llist,"\|")); } } was one way to conserve memory in SL when adding more data to something large. In SL llist will become ["a","b","c"]; However is OpenSim XEngine (at least) llist will become ["c"] Is this a bug, or should we stop using OpenSim for SL development due to divergence in how things work? However.. Code: default { state_entry() { list llist = ["a","b"]; llist += (llist=[]) + ["c"]; llSay(0, llDumpList2String(llist,"\|")); } } ..works the same in both SL and OpenSim. OpenSim warning: "Warning: Multiple assignments to 'list' at line 5 column 19; results may differ between LSL and OSSL." __________________ Χάος \| HomeSecurity Orb - the original security orb \| Psyke's AjaxLife - Free web SL access.

03-07-2009, 04:55 AM	#8 (permalink)
ZATZAi Senior Member Join Date: Jun 2007 Location: California Posts: 2,525 XBOX Leaderboard: 12^th	That's a rather lively mantis report... __________________ - ZATZAi

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03-06-2009, 08:48 PM	#2 (permalink)
Kristian stored in the cloud SLU Supporter PHIL LINDEN SKULLFCKED ME RIGHT HERE* Join Date: Jun 2007 Posts: 4,866 My Mood: SL Join Date: 2/26/2005	Any divergence in the scripting lanuage should be considered a bug, I would think.

03-06-2009, 10:21 PM	#4 (permalink)
Psyke Phaeton Senior Member SLU Supporter Running 'round in Circle's Join Date: Sep 2007 Location: Australia Posts: 6,949 My Mood: SLShopper Ads: 1 SL Join Date: 12-Oct-2003 Business: Psyke's Defence Systems Blog Entries: 3	Even so it begs the bigger question. Can OpenSim in the future be used to develop for SecondLife? Or will the differences become too much. Whilst I agree that having to do the above to save memory is stupid, it is extremely useful when limited to 64kb. It would become tedious if, to develop code on OpenSim, we had to edit it after transfering to SL. I hope they keep 100% "goofy" LSL compatibility whilst also developing all the other compatibilities.

03-06-2009, 10:34 PM	#5 (permalink)
Beezle Warburton Senior Member Beeble Bubble Bimbo Join Date: Aug 2007 Location: Darkmere Posts: 3,885 My Mood: SLShopper Ads: 22 SL Join Date: October 24, 2006 Business: Cortech Enterprises	It's tricky to ensure compatibility for things that are basically hacks that work on sluggish processors.

03-07-2009, 12:58 AM	#7 (permalink)
Psyke Phaeton Senior Member SLU Supporter Running 'round in Circle's Join Date: Sep 2007 Location: Australia Posts: 6,949 My Mood: SLShopper Ads: 1 SL Join Date: 12-Oct-2003 Business: Psyke's Defence Systems Blog Entries: 3	I guess I had better update my OpenSim

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