[Opensim-users] use of C# in scripts

[Serendipity Seraph]

Also been tempted by idea of writing in whatever language I like and
targeting vanilla LSL.  :)


On Tue, Feb 26, 2019 at 12:33 PM Serendipity Seraph <seren.seraph at gmail.com>
wrote:

> javascript and embedded V8 engine?  Particularly something node-ish with
> easy of protocol handling, event handling, async event loop at its core
> seems very reasonable for handling a LSL event driven scripting needs.  Of
> course you can do much the same in async python and some other languages.
>   Heve been tempted once or twice to make some hack to get some lisp or
> scheme-ish script.   Or for that matter to hack a LSL intrepreter/debugger
> or embedded language in same.
>
> On Tue, Feb 26, 2019 at 12:28 PM Serendipity Seraph <
> seren.seraph at gmail.com> wrote:
>
>> As a software engineer the things that deeply bug me about LSL include:
>>
>> 1) no real way to get reuse vs copy and paste where needed.  Major blow
>> to possible efficiency gains of not having multiple copies and to
>> maintainability.  No import/include or library concept or support.
>>
>> 2) almost no real data structures  and no way to roll your own.  Yeah you
>> can do 1970s era hacks sort of.
>>
>>
>> On Tue, Feb 26, 2019 at 12:24 PM Serendipity Seraph <
>> seren.seraph at gmail.com> wrote:
>>
>>> AFAIK the JVM garbage collection is as efficient as Lisp garbage
>>> collection.  In fact some of the same people worked on both.  And much of
>>> this tech was used in the C# underlying CLR as well.  So I doubt very much
>>> that GC is a critical issue, especially in small opensim scripts.
>>>
>>> On Sun, Feb 24, 2019 at 4:00 AM Ethan Gardener <eekee57 at fastmail.fm>
>>> wrote:
>>>
>>>> On Sat, Feb 23, 2019, at 8:11 PM, Dr Ramesh Ramloll wrote:
>>>> > I think the assumption that C# should work only in closed secure
>>>> > environments kind of narrows down the application space by quite a
>>>> bit,
>>>> > like 90% or more.
>>>>
>>>> Yeah.  It narrows it down to about the same space as custom modules, so
>>>> why not write them instead?
>>>>
>>>> This is one area where I wish OpenSim had branched out a bit; adding
>>>> other languages, but I guess there was no-one to work on it.  I wasn't up
>>>> to the task myself, as much as I wished I was.  Making a safe interpreter
>>>> is non-trivial anyway.  Lately, I've been looking at one of the problems,
>>>> avoiding memory leaks (which could lead to a denial of service attack or
>>>> possibly an overflow exploit).  This alone is not at all easy to solve
>>>> efficiently.  It would be better if modern computers descended from the
>>>> Lisp Machines of the 1980s, they had hardware support for automatic garbage
>>>> collection, but instead we have virtual memory schemes which make it hard
>>>> for garbage collectors to work efficiently.  (I don't think anyone really
>>>> wants to pay for the extra bits this needs.  The cost of memory was a huge
>>>> limiting factor through the '80s and much of the '90s, and remains a little
>>>> bit of a problem today.)
>>>>
>>>> I can solve my problems with a relatively inefficient design, but that
>>>> would be ridiculous in an environment where a single simulator may have to
>>>> run thousands of scripts.  I could hypothetically write a full-blown
>>>> garbage collector, but it's not worth it because such garbage collectors
>>>> are notoriously prone to bugs, and *still* have efficiency problems.
>>>> Garbage collectors are one of those things which exponentially approach
>>>> infinite complexity as they approach correctness and efficiency.
>>>>
>>>> Is a simple, efficient design possible?  Yes... if you limit the
>>>> possible data structures.  ;)  Particularly, never allow complex data types
>>>> to contain references to other complex data types, that prevents reference
>>>> loops which are *the* problem requiring complex garbage collectors.  I
>>>> haven't chosen this for my comparatively inefficient design, I've chosen to
>>>> make all data structures immutable; if you want to change something, you
>>>> have to copy the structure.  That way, it's impossible for a structure to
>>>> contain a reference to itself because the structure becomes immutable
>>>> before the public reference to it exists.  This very much goes against the
>>>> grain, I've been exploring every other way of doing it, but I figure if
>>>> it's good enough for high finance it ought to be good enough for me.  I
>>>> wonder if it might actually be good enough for OpenSim.  Maybe I'll run
>>>> some experiments comparing scale, but my system probably won't be ready for
>>>> that for a long time yet.  My health isn't
>>>>  helping me get on with it.
>>>> _______________________________________________
>>>> Opensim-users mailing list
>>>> Opensim-users at opensimulator.org
>>>> http://opensimulator.org/cgi-bin/mailman/listinfo/opensim-users
>>>>
>>>