eq?/eqv? hash tables with rehashing on gc,

as in larceny, may be doing more work than

is needed for some common eq?/eqv? cases.

If the keys are only symbols, it would be

reasonable to store a hash value directly in

the symbol object, or even arrange for all

symbols to be stationary in the gc.  To allow

such optimizations, I think we should add:

make-symbol-hash-table

(which may just be the same as an eq table.)

Similarly, a possibly rehashing eqv table is

overkill for characters and numbers when we

can just construct normal comparison-based

hash tables using:

number-hash

One could also consider char-ci-hash, though

case comparisons on single chars may be

indicative of poor design.

-- 

Alex