Hi Khanh,

Sounds excellent!  One note on integration ease/etc.  In general S4 is
toxic.

Is there a particular reason for using S3 over S4?  I realize this isn't
on-topic per se, but it will affect other packages ability to use (and use
in general, as interoperability is the name of the game these days)

S4 really isn't excellent for much at present, in my biased though rather
lengthy experience in this area.

Aside from general obfuscation and bugginess to S4 itself, the only other
thing it can do that S3 can't do directly is dispatch on multiple args and
provide some sort of protection with respect to types per slot.

If we restrict to a paradigm where objects only are altered with accessor
functions (recommended), then all the type checking can be handled there.
 Multiple args as far as I can tell don't/won't come into play here though.
 At least not in a way that would warrant all the "bad" of S4.

Additionally S4 is not overly friendly to large objects, as any slot
manipulation does a full object copy.  Order book is large almost by
definition.

As another possible point of interest, you could take a look at the RTAQ
package to see what they did for TAQ data.

Take it or leave it, for general widespread use and all the benefits of
that, S4 isn't going to be a friend on this.

Awesome potential and work thus far though, and awesome work so far on
RQuantLib et al...

My [S]3c. ;-)

Jeff

On Wed, Jun 9, 2010 at 12:27 PM, Khanh Nguyen <nguyen.h.khanh@gmail.com>wrote:

> Hello,
>
> I am working with Andraw Liu, under the supervision of David Kane and
> Jeff Enos ("backtest" and "portfolio" packages) to create a Limit
> Order Book package that will model a limit order book.
>
> Our initial version of the package is on R-Forge at
> https://r-forge.r-project.org/projects/limitob/
>
> We would appreciate suggestions and comments as to what functionality
> the package should have. Currently, we have implemented the following
> functions
>
> --- "show", "summary", "plot", "display",
> --- "best.bid", "best.ask",
> --- "bid.price.levels", "ask.price.levels", "total.price.levels",
> --- "bid.orders", "ask.orders", "total.orders",
> --- "mid.point", "inside.market", "spread", "snapshot",
> ---  "add.order", "remove.order", "replace.order", "market.order"
>
> Additionally, we were wondering what a good name for the package would
> be--Limit Order Book sounds kind of clunky and we were thinking that
> maybe "order.book", "orderbook", "limitorderbook",  simply "lob" would
> work better. Suggestions on that would be helpful too!
>
> We will summarize any responses we receive and send an email to the
> listserv in a week.
>
> Regards,
>
> Andrew and Khanh
>
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>



-- 
Jeffrey Ryan
jeffrey.ryan@insightalgo.com

ia: insight algorithmics
www.insightalgo.com

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