2954     string toISOExtString() const @safe pure nothrow  in toISOExtString()  function
2960             toISOExtString(w);  in toISOExtString()
2967     void toISOExtString(W)(ref W writer) const
2971         _date.toISOExtString(writer);
2983         assert(DateTime(Date(2010, 7, 4), TimeOfDay(7, 6, 12)).toISOExtString() ==
2986         assert(DateTime(Date(1998, 12, 25), TimeOfDay(2, 15, 0)).toISOExtString() ==
2989         assert(DateTime(Date(0, 1, 5), TimeOfDay(23, 9, 59)).toISOExtString() ==
2992         assert(DateTime(Date(-4, 1, 5), TimeOfDay(0, 0, 2)).toISOExtString() ==
2999 …    assert(DateTime(Date(9, 12, 4), TimeOfDay(0, 0, 0)).toISOExtString() == "0009-12-04T00:00:00");
3000 …  assert(DateTime(Date(99, 12, 4), TimeOfDay(5, 6, 12)).toISOExtString() == "0099-12-04T05:06:12");
3001 …assert(DateTime(Date(999, 12, 4), TimeOfDay(13, 44, 59)).toISOExtString() == "0999-12-04T13:44:59"…
3002 …assert(DateTime(Date(9999, 7, 4), TimeOfDay(23, 59, 59)).toISOExtString() == "9999-07-04T23:59:59"…
3003 …assert(DateTime(Date(10000, 10, 20), TimeOfDay(1, 1, 1)).toISOExtString() == "+10000-10-20T01:01:0…
3006 …   assert(DateTime(Date(0, 12, 4), TimeOfDay(0, 12, 4)).toISOExtString() == "0000-12-04T00:12:04");
3007 …  assert(DateTime(Date(-9, 12, 4), TimeOfDay(0, 0, 0)).toISOExtString() == "-0009-12-04T00:00:00");
3008 …assert(DateTime(Date(-99, 12, 4), TimeOfDay(5, 6, 12)).toISOExtString() == "-0099-12-04T05:06:12");
3009 …assert(DateTime(Date(-999, 12, 4), TimeOfDay(13, 44, 59)).toISOExtString() == "-0999-12-04T13:44:5…
3010 …assert(DateTime(Date(-9999, 7, 4), TimeOfDay(23, 59, 59)).toISOExtString() == "-9999-07-04T23:59:5…
3011 …assert(DateTime(Date(-10000, 10, 20), TimeOfDay(1, 1, 1)).toISOExtString() == "-10000-10-20T01:01:…
3015         assert(cdt.toISOExtString() == "1999-07-06T12:30:33");
3016         assert(idt.toISOExtString() == "1999-07-06T12:30:33");
3109         `toISOExtString`, `toSimpleString`, or some other custom formatting
3732     assert(dt.toISOExtString() == "2000-06-11T10:31:40");
7108             assert(reversed == date, date.toISOExtString ~ " != " ~ reversed.toISOExtString);
7404     string toISOExtString() const @safe pure nothrow  in toISOExtString()  function
7410             toISOExtString(w);  in toISOExtString()
7419         assert(Date(2010, 7, 4).toISOExtString() == "2010-07-04");
7420         assert(Date(1998, 12, 25).toISOExtString() == "1998-12-25");
7421         assert(Date(0, 1, 5).toISOExtString() == "0000-01-05");
7422         assert(Date(-4, 1, 5).toISOExtString() == "-0004-01-05");
7428         assert(Date(9, 12, 4).toISOExtString() == "0009-12-04");
7429         assert(Date(99, 12, 4).toISOExtString() == "0099-12-04");
7430         assert(Date(999, 12, 4).toISOExtString() == "0999-12-04");
7431         assert(Date(9999, 7, 4).toISOExtString() == "9999-07-04");
7432         assert(Date(10000, 10, 20).toISOExtString() == "+10000-10-20");
7435         assert(Date(0, 12, 4).toISOExtString() == "0000-12-04");
7436         assert(Date(-9, 12, 4).toISOExtString() == "-0009-12-04");
7437         assert(Date(-99, 12, 4).toISOExtString() == "-0099-12-04");
7438         assert(Date(-999, 12, 4).toISOExtString() == "-0999-12-04");
7439         assert(Date(-9999, 7, 4).toISOExtString() == "-9999-07-04");
7440         assert(Date(-10000, 10, 20).toISOExtString() == "-10000-10-20");
7444         assert(cdate.toISOExtString() == "1999-07-06");
7445         assert(idate.toISOExtString() == "1999-07-06");
7449     void toISOExtString(W)(ref W writer) const
7471         Date(2010, 7, 4).toISOExtString(w);
7474         Date(-4, 1, 5).toISOExtString(w);
7575         `toISOExtString`, `toSimpleString`, or some other custom formatting
8295     assert(d.toISOExtString() == "2000-06-11");
9098     string toISOExtString() const @safe pure nothrow  in toISOExtString()  function
9104             toISOExtString(w);  in toISOExtString()
9111     void toISOExtString(W)(ref W writer) const
9121         assert(TimeOfDay(0, 0, 0).toISOExtString() == "00:00:00");
9122         assert(TimeOfDay(12, 30, 33).toISOExtString() == "12:30:33");
9130         assert(tod.toISOExtString() == "12:30:33");
9131         assert(ctod.toISOExtString() == "12:30:33");
9132         assert(itod.toISOExtString() == "12:30:33");
9149         `toISOExtString`, or some other custom formatting function that
9166         return toISOExtString();  in toString()
9173         toISOExtString(writer);
9626     assert(t.toISOExtString() == "12:41:40");