That's a good point, and I will consider it.  However, it might make more sense for bitvectors to have the SRFI 151 API rather than the SRFI 133 API.  Then the only difference between bitvectors and SRFI 151 would be that bitvectors would be mutable, whereas integers are immutable.  What do you think?

On Tue, May 22, 2018 at 6:03 PM, Per Bothner <xxxxxx@bothner.com> wrote:
Some Scheme implementations (including Guile and Kawa) have bit vectors.
So does Common Lisp.  Does any Scheme have u1vectors?

A bitvector and a u1vector are "equivalent" except that the former stores
#f/#t while the latter stores exact integers 0/1; however, the low-level
data structures (and performance issues) are the same.  I don't know
which of bitvector or u1vector is a priori more useful, elegant,
or "mathematically" consistent.  However, given existing art for bitvectors
adding u1vectors seems to have limited benefit.  I suggest instead
standardizing bitvector.
--
        --Per Bothner
xxxxxx@bothner.com   http://per.bothner.com/