I was trying to add Linden Script Language to Notepad++ *without* using the User Defined Language, since I wished to share my work with Notepad++ community, but I failed. I modified langs.xml by adding

<Language name="lsl" ext="lsl" commentLine="//" commentStart="" commentEnd="">
    <Keywords name="instre1">default do else for if jump return state while</Keywords>
    <Keywords name="instre2">llAbs llAcos llAddToLandBanList ...</Keywords>
    <Keywords name="type1">float integer key list quaternion rotation string vector</Keywords>
    <Keywords name="type2">at_rot_target at_target attach ...</Keywords>           
    <Keywords name="type3">ACTIVE AGENT ALL_SIDES ATTACH_HUD_CENTER_2 ...</Keywords>
</Language>

I also changed styles.xml by adding

<LexerType name="lsl" desc="Linden Script Language" ext="">
   <WordsStyle name="DEFAULT" styleID="3" fgColor="000000" ... />
   <WordsStyle name="FLOW CONTROL" styleID="4" fgColor="0000FF" ... keywordClass="instre1" />
   ...
   <WordsStyle name="COMMENT LINE" styleID="2" fgColor="008000" ... />
</LexerType>

and added lsl.api in plugins\APIs

default
do
else
for
if
jump
...
VEHICLE_TYPE_SLED
ZERO_ROTATION
ZERO_VECTOR

No way. At last, after many tries, I decided to use the User Defined Language. It works, but

1. it gives me no way to specify five keywords types, but only four, so that I had to mix TYPES and EVENTS.
2. if I specify / as operator, // is no more parsed as start of comment (this is a bug, I suspect).

Is it possible to take advantage of my work to add LSL to next version of Notepad++ ?