Re: Embedding a limited interpreter in a SISC Scheme application.

On Tue, Mar 13, 2007 at 09:48:53AM -0300, Igor Hjelmstrom Vinhas Ribeiro wrote:
> Hello everyone!
> 
>    I am creating one application in Scheme/SISC  and I would like that the
> user of the application could extend it using Scheme. However I would need the
> user to have access to a limited subset of what SISC can do.
> 
>    A few closures will be available for the user. For instance:
> 
> (buy-stock-when <stock-code> <amount>
> <threshold-after-which-start-buy> <stop-loss-minimum-value>)
> 
> (current-stock-price <stock-code>)
> 
> 
>    I just want users to have the full power of Scheme/SISC as one algorithm
> designing language while not allowing them to wreak havoc in the system they are
> using.

Take a look at the implementation of Sarahbot, an IRC bot in SISC.  It 
can be found in the contrib module of SISC's CVS, in the 
irc/scheme/sarah subdirectory.  In particular, look at 
plugins/scheme.scm, which uses SISC's symbolic environments 
functionality to present just the Scheme R5RS environment to users of 
IRC channels, and removes dangerous functions.  You can use this as a 
starting point, then add procedures you want the users to have using 
getprop/putprop into that environment.  

It does not check for memory requirements at the moment, only a rough 
elapsed time.  You may be able to use S2J to bridge to functionality in 
the java.lang.management package to monitor memory or cpu time more 
thoroughly.

   Scott

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