> I don't know why all the withdrawn SRFIs were withdrawn, so it should
> definitely be optional.  Also, I would prefer that it be a symbol rather
> than English text, e.g. the symbol r6rs would represent something both
> introduced and withdrawn as part of the R6RS effort.  I could convert
> that into more explanatory English where appropriate.

Sounds good.

> Perhaps this optional data should not be specifically about the reasons
> for withdrawal, but about the project that the SRFI was part of, again
> e.g. R6RS.  Then we could have a r7rs-large symbol, too, which would
> mean something entirely different.

Good idea.

> Actually, I already have a keywords field in the database.  This might
> be a good use for that.  Until now, I've used that only for the topic
> category of SRFI, but by generalizing its purpose, we'll automatically
> get the ability to show subsets like R6RS SRFIs through the existing
> UI.  In the process, I might turn all the keywords into symbols.

Even better!

My experience concurs that a "single category per item" system tends to
run into unforeseen limitations whereas the flexiblity of "multiple tags
per item" has always saved the day.

> Now I just need to figure out exactly which SRFIs were withdrawn for
> R6RS.  It shouldn't be too hard.

John Cowan can probably help solve any ambiguous cases.