Scripting language

[jstreich]

I'm working on a graphical MUD, and I'm thinking about making a scripting (or other meta-) language that will allow a super user/world builder to create a script to attach to an item. When a user uses the item the script is "run".

I think I know how I'm going "run them" and I have an idea about what the language looks like, but I'm having trouble figguring out how to parse the language fast and effeciently. I'm thinking I can parse the language into an array of "actions" when the script is added/loaded -- and then when the action occurs, perform it. This means that the JVM will have a bunch of loaded scripts ready to run, even if they aren't used (or used once) and then I'm using a lot memory needlessly -- but if I reread/parse the script when actions happen, then I am taking too much CPU time when an action is performed.

[plug=shameless]

http://game-master.us/phpx-3.4.0/

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[sedj]

I would certainly preload the scripts/actions - memory is cheap and and doubt these scripts would take up much memory - but speed in these things is everything, and I would rather sacrifice memory over speed

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[timw]

... or you could write a 'script cache' so that often used scripts are more readily available.

Tim
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"Your morbid fear of losing,
destroys the lives you're using." - Ozzy

 

[jstreich]

I would certainly preload the scripts/actions - memory is cheap and and doubt these scripts would take up much memory - but speed in these things is everything, and I would rather sacrifice memory over speed

Memory might be cheap, but I don't have a dedicated server for it (yet)...

... or you could write a 'script cache' so that often used scripts are more readily available.

Tim

That's not a bad idea, but memory managment is still in the hands of the JVM, so releasing a script to load another won't free the memory when I "release" it -- but when the GC runs.

[plug=shameless]

http://game-master.us/phpx-3.4.0/

[/plug]

 

[timw]

releasing a script to load another won't free the memory when I "release" it -- but when the GC runs

Well yes, but it does get released at some point, and sooner under heavier memory loads.

Tim
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"Your morbid fear of losing,
destroys the lives you're using." - Ozzy

 

[jstreich]

Well yes, but it does get released at some point, and sooner under heavier memory loads.

Tim

What I fear this scenario:
1. Cache is full and has script A as the least recently used in cache.
2. User uses item with script X in it.
3. X is loaded into the cache, A is released
4. Another user uses an item with script A attached,
B is released and A is loaded into it's spot.

At the end, I have 2 copies of A in memory, one without a handle to it -- waiting to be GC'd. I realize that with a cache bad timing will always happen every now and again, but with garbage collection, it'd be a very bad thing to have happen. Not to mention memory and CPU the caching would take up... Perhaps there is a way to make each script take up a smaller amount of memory?

[plug=shameless]

http://game-master.us/phpx-3.4.0/

[/plug]

 

[stefanwagner]

Fast CPUs are cheap to.

Rule 2 of Optimization is:
First program according to the KISS principal: Keep it simple, stupid.
Then test and measure.
Never believe your assumptions.
In most circumstances performance-tuning isn't necessary.
It's wasted development-time and introducing new bugs.

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