Hello Alex,

I just tried the reference implementation in CHICKEN, but it gave me
several warnings upon load, and errors when trying to use something:

Note: the following toplevel variables are referenced but unbound:

  substring-cursor (in rx-match-submatch/list)
  string-offset->index (in rx-match-submatch-start+end)
  string-offset->index (in rx-match-submatch-start+end)
  string-cursor? (in rx-match-submatch-start+end)
  string-cursor? (in rx-match-convert)
  substring-cursor (in rx-match-convert)
  string-cursor? (in rx-match-convert)
  string-cursor? (in rx-match-convert)
  substring-cursor (in rx-match-convert)
  string-cursor? (in rx-match>=?)
  string-cursor? (in rx-match>=?)
  string-cursor=? (in rx-match>=?)
  string-cursor>? (in rx-match>=?)
  string-cursor<? (in rx-match>=?)
  string-cursor? (in rx-match>=?)
  string-cursor? (in rx-match>=?)
  string-cursor<? (in posse-advance!)
  string-cursor-ref (in posse-advance!)
  string-cursor=? (in regexp-run)
  string-cursor>=? (in regexp-run)
  string-cursor-ref (in regexp-run)
  string-cursor-next (in regexp-run)
  string-end-arg (in regexp-run)
  string-start-arg (in regexp-run)
  string-cursor=? (in match/bos)
  string-cursor>=? (in match/eos)
  string-cursor-ref (in match/bol)
  string-cursor-prev (in match/bol)
  string-cursor=? (in match/bol)
  string-cursor-ref (in match/eol)
  string-cursor>=? (in match/eol)
  string-cursor<? (in match/bow)
  string-cursor-ref (in match/bow)
  string-cursor-prev (in match/bow)
  string-cursor=? (in match/bow)
  string-cursor>=? (in match/eow)
  string-cursor>? (in match/eow)
  string-cursor-ref (in match/eow)
  string-cursor-prev (in match/eow)
  string-cursor-next (in regexp-fold)
  string-offset->index (in regexp-fold)
  string-offset->index (in regexp-fold)
  string-cursor<? (in regexp-fold)
  string-end-arg (in regexp-fold)
  string-start-arg (in regexp-fold)
  string-concatenate (in regexp-replace)
  substring-cursor (in regexp-replace)
  string-index->offset (in regexp-replace)
  substring-cursor (in regexp-replace)
  string-index->offset (in regexp-replace)
  string-concatenate-reverse (in regexp-replace-all)
  substring-cursor (in regexp-apply-match)

Is this some sort of library that's missing?  None of these procedures
are mentioned in the R7RS-small document.  The SRFI-115 text only
mentions SRFI-14, SRFI-33 and SRFI-69.

Cheers,
Peter
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