On 8/1/10 12:12 PM, austin seipp wrote:
Hi Jason,
I've had my eye on the 'Takusen' approach for a while. In particular I
think it's a wonderful idea to use the left-fold based interface.
Takusen is also well supported and pretty stable, having been around
for a while.
I agree; in fact, I use it for all of my database needs.
* It would be nice if we could make it depend on nicer libraries
instead of rolling its own stuff - for example, we have Lato's
excellent iteratee package, and Bas van Dijk has written a (IMO
woefully underappreciated!) 'regions' package with encapsulate the
lightweight monadic regions idea Oleg proposed. Of course, due to
design, neither of these may work properly for Takusen's case, and if
they did they would very likely facilitate API changes, but it's
something I've been thinking about in the name of making the library
smaller and more lightweight.
Making the library depend on more external libraries will actually make
it more "heavyweight" since it will require the user to install more
libraries just in order to use Takusen. I'm not saying that this is a
bad thing, but I wouldn't automatically count it as a disadvantage that
one can install Takusen without requiring lots of other libraries to be
installed first.
It looks to me like the iteratee package wouldn't be a good fit for
Takusen because (as far I understand it) it is designed for the use case
of reading raw data where in particular the "chunks" might not be
aligned with the records being processed, whereas Takusen is designed
for reading in very structured data. The regions package might work,
although there are problems with the way that it handles exceptions that
has been discussed previously on this list.
Finally, a disadvantage of changing Takusen to use these kinds of
external libraries is that it could actually make it *harder* to
understand how to use it, since first the user would have to understand
the concepts involved in the external libraries.
Again, I'm not saying that any of these issues automatically make it a
bad idea to modify Takusen to use external libraries, just that the
current approach works well and is (in my opinion) already relatively
simple and straightforward, and it would be unfortunate if this were
lost without a clear benefit.
Cheers,
Greg
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