Zefram <zef...@fysh.org> writes: > The date->string function from (srfi srfi-19), used on ISO 8601 formats > "~1", "~4" and "~5", for years preceding AD 1, has an off-by-one error: > > scheme@(guile-user)> (use-modules (srfi srfi-19)) > scheme@(guile-user)> (date->string (julian-day->date 0 0) "~4") > $1 = "-4714-11-24T12:00:00Z" > > The date in question, the JD epoch, is 24 November 4714 BC (in the > proleptic Gregorian calendar). In ISO 8601 format, that year is properly > represented as "-4713", not "-4714", because ISO 8601 uses the AD era > exclusively. 4714 BC = AD -4713.
I agree that this is definitely a bug, but I'm nervous about deviating from the SRFI-19 reference implementation, and therefore probably from most other implementations of SRFI-19, in this way. I think that this bug should be reported to the SRFI-19 mailing list. https://srfi.schemers.org/srfi-19/ There have been several other bugs reported and fixed in upstream SRFI-19 over the years, including some as recently as June 2017, so I'm hopeful that they will take this bug seriously and issue a fix. Would you like to report it to them? Mark
