I just published the source code and
documentation for Harold Ancell's the
Chibi Scheme example implementation of
SRFI 170.  Here's a summary of the commits:

  Commit Summary
    - initial versions
    - lots more details
    - small improvements and spell checking
    - added 0.8.0 Makefile and lib-tests.scm
    - improvements and additions from testing
    - add the example implementation files

  File Changes
    A srfi/170.sld (141)
    A srfi/170/170.scm (743)
    A srfi/170/170.stub (494)
    A srfi/170/COPYING (31)
    A srfi/170/TODO.txt (8)
    A srfi/170/aux.c (386)
    A srfi/170/common.scm (40)
    A srfi/170/test.sld (591)
    A srfi/174.sld (17)
    A srfi/MANIFEST (20)
    A srfi/Makefile (536)
    A srfi/Makefile-0.8.0 (522)
    A srfi/README (61)
    A srfi/lib-tests.scm (125)
    A srfi/lib-tests.scm-0.8.0 (119)

Thank you very much, Harold, for this contribution!