User talk:Omei Qunhua

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Revision as of 12:11, 30 December 2012 by Pedro Oval (Talk | contribs)

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An appeal:

When submitting sample scripts (or editing existing samples) PLEASE ensure you've tested the resulting script. There can be no excuse for blindly editing and not testing, and certainly no excuse for submitting scripts that won't even compile! Omei Qunhua 09:02, 9 December 2012 (PST)

I wholeheartedly agree. I have been guilty of the sin but I agree. lslint and lsleditor are our friends. I noticed you mentioned that some edits have been breaking examples. If that happens, please make a note of it somewhere, we need to keep track of this so we can halt any negative trends. -- Strife (talk|contribs) 08:34, 14 December 2012 (PST)
Well if you want to observe a negative trend, the following Wiki pages / examples were all corrupted by the same person :)
Wiki Page                 Date Corrupted         Nature of Error

Gun Script                  18-Oct-12            Compile error

llGetAgentList               8-Dec-12            Compile error  

llGetAgentList               9-Dec-12            Run-time bad results 

llDialog                    24-Sept-12           Compile error

11SetLinkAlpha              30-Sept-12           Compile error

llGetLinkInventoryPermMask  25-Nov-12            Compile error

llResetOtherScript          24-Sept-12           Run-time error

llGetSimStats                8-Dec-12            Compile error

llRequestURL                24-Sep-12            Compile error

llSetKeyframedMotion        24-Sep-12            Run-time error

llEvade                      4-Dec-12            Compile error

llGetClosestNavPoint         4-Dec-12            Compile error

llGetNotecardLine           23-Sept-12           Run-time bad results

StringIsNum                  7-Oct-12            Compile error

Sensor                      28-Oct-12            Compile error and Run time wrong results


(I've also corrected 4 other non-compilable or faulty example scripts by other editors, where the errors have existed since July 2012, March 2008, and Sept 2007)

Omei Qunhua 15:26, 18 December 2012 (PST)

I have take a look at all his changeings in the example scripts and do not agree with the most, Everywhere he remove inside the sub-if's the clamps and resort the events. The most of the experienced scripters do not realy read it, but for beginners i think its bad when they not see where are the clamps necessary and where not. Daemonika Nightfire 10:19, 20 December 2012 (PST)

More size constructs

I've confirmed your results and made a few more tests of size optimization constructs.

x=-~x;               6 bytes (equivalent to ++x)
x=~-x;               6 bytes (equivalent to --x)
y=-~x;               6 bytes (equivalent to y=x+1)
if(~x);              7 bytes (equivalent to if(x!=-1))
x*2;                 8 bytes (equivalent to x<<1)
x=-~-~x;             8 bytes (equivalent to x+=2)
x=~-~-x;             8 bytes (equivalent to x-=2)
y=x+1;              10 bytes
x=x*2;              10 bytes (equivalent to x=x<<1)
x*=2;               10 bytes
if (!~x);           10 bytes (equivalent to if(x==-1))
if(x&0x80000000)    12 bytes (equivalent to if(x<0) for integers)
if(x<0);            13 bytes
x=x<<1;             14 bytes
if(x!=-1);          17 bytes

For float x:

x=0;                 9 bytes
x=0.0;              12 bytes

For vector x:

x=<0, 0, 0>;        27 bytes
x=<0.0, 0.0, 0.0>;  36 bytes
x=ZERO_VECTOR;      36 bytes

for list x:

llGetListLength(x); 40 bytes
x!=[];              13 bytes (note: only list LENGTH is compared - actually subtracted. That returns 0 for empty list.)
x==[];              13 bytes
if(x==[]);          17 bytes
if(x!=[]);          17 bytes
x!=[""];            23 bytes (note: only list LENGTH is compared - actually subtracted. That returns -1 for empty list.)
x==[""];            23 bytes (true if x has 1 element)
x!=[[]];            23 bytes (list may not contain lists but this is allowed?!?!)
x==[[]];            23 bytes
if(x==[""]);        27 bytes
x!=[1];             28 bytes (true if x has 1 element)
if(x==["","",""]);  47 bytes
if(x!=["","",""]);  47 bytes
if(llGetListLengt(x)==1);  53 bytes
if(llGetListLengt(x)!=1);  56 bytes
if(x==["","","",""]);      57 bytes

Some of those may be worth being included in LSL Hacks, which I'd say is the place for code size optimization. Your list results are run time size related and thus worth being included as an update to LSL Script Memory. --Pedro Oval 09:35, 29 December 2012 (PST)

Wow some of those are really interesting. I would venture the reason float zero is so expensive is how it's being encoded (there are several ways to encode floats in IL). They haven't optimized the zero case. I'm very surprised that x * 2 is less than x << 2. -- Strife (talk|contribs) 13:28, 29 December 2012 (PST)
Well try these for size ... x+x; 4 bytes, x=x+x; 6 bytes, x=x^x; 6 bytes. Food for thought! Omei Qunhua 06:05, 30 December 2012 (PST)
VERY interesting, thank you!!! --Pedro Oval 12:11, 30 December 2012 (PST)

Some more interesting results (all for LOCAL variables):

integer a;           49 bytes
integer a=0;         53 bytes
string a="";         53? 55? bytes (I'm unsure if there's a preexisting instance of "" or not - my measuring method can't tell)
string a;            53? 55? bytes
string a="a";        53 bytes plus 2*(num characters+1) per each different string (equal strings are referenced just once)
float a=0;           54 bytes
list a;              55 bytes
list a=[];           55 bytes
float a;             57 bytes
float a=0.0;         57 bytes
key a="";            60? 61? 62? bytes (same problem as string)
key a="string";      60? bytes + 2*(num_characters+1) per each different string

Braces don't seem to add anything: {integer a;} occupies the same size as integer a; and so on. Since the string case is complex, let me put an example. string a="aaa"; string b="aaa"; will use 53+53+2*(3+1)=114 bytes, because the string is the same in both cases and it's reused, but string a="aaa"; string b="bbb"; will use 53+53+2*(3+1)+2*(3+1)=122 bytes because the strings are different.

I'm getting inconsistent results with the keys. Something else seems to be going on. I get 61 bytes sometimes and 60 others. Wonder if there's a byte alignment problem. If so, that could make some of the previous measurements incorrect, even if they looked consistent. --Pedro Oval 13:40, 29 December 2012 (PST)