<!DOCTYPE html><html><head><title></title><style type="text/css">p.MsoNormal,p.MsoNoSpacing{margin:0}</style></head><body><div>I wrote my own TZDB parser as well, and my early versions ran into these problems. The solution was to implement an internal version of the "date/time" class/type that could handle 24:00 without complaining. Your code will have to handle Japan's bizarre 25:00 rule for 1948-1951 anyway (Rule Japan 1948 1951 - Sep Sat>=8 25:00 0 S). Once it handles 25:00, it should be able to handle the 24:00.<br></div><div><br></div><div>I don't speak for the TZDB maintainers, but my impression is that these 24:00 correspond directly to how the regulations and laws are written. That probably makes it easier for human beings to maintain them.<br></div><div><br></div><div>On Tue, Apr 4, 2023, at 02:49, Jacob Pratt via tz wrote:<br></div><blockquote type="cite" id="qt" style=""><div dir="ltr"><div>While writing a parser for tzdb files, I noticed that some rules are for a given date at 24:00, rather than the following day at 0:00. While in some cases this is unavoidable (Egypt), in others there is no reason this is necessary (Belize).<br></div><div><br></div><div>I think it would be reasonable to change 24:00 to 0:00 where possible, incrementing the day, day of week, and month as appropriate. This would reduce the need for special casing values to those that have a technical reason.<br></div><div><div><div dir="ltr" class="qt-gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><br></div><div>Jacob Pratt<br></div></div></div></div></div></div></div></div></blockquote><div><br></div></body></html>