Missing docs for working with negative years

editions/tw5.com/tiddlers/concepts/Date Fields.tid

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+created: 20150117190213631
+modified: 20201201154211507
+tags: Concepts
+title: Date Fields
+type: text/vnd.tiddlywiki
+
+Certain [[fields|TiddlerFields]] of a tiddler are used to store dates and times. TiddlyWiki supports dates from the year -9999 to the year 9999.
+
+The two standard date fields are <<.field created>> and <<.field modified>>.
+
+Values of date fields are 17 or 18-character strings:
+
+* <<.from-version "5.1.23">> an optional minus sign `-` to indicate a negative year
+* 4 digits for the year
+* 2 digits for the month
+* 2 digits for the day
+* 2 digits for the hour
+* 2 digits for the minute
+* 2 digits for the second
+* 3 digits for the millisecond
+
+To avoid problems arising from differences of time zone, TiddlyWiki always uses [[UTC|https://en.wikipedia.org/wiki/Coordinated_Universal_Time]].
+
+As an example, the <<.field created>> field of this tiddler has the value <<.value """<$view field="created"/>""">>.
+
+Dates can be [[converted to other formats|DateFormat]] for display:
+
+<$macrocall $name="wikitext-example-without-html"
+src="""<$view field="created" format="date" template="DDD DDth MMM YYYY"/>""">

editions/tw5.com/tiddlers/features/DateFormat.tid

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+created: 20140418142957325
+modified: 20201201154521138
+tags: Features
+title: DateFormat
+type: text/vnd.tiddlywiki
+
+When used to display date values (with the `format` attribute set to ''date''), the ViewWidget accepts a `template` attribute that allows the format of the date values to be specified. The format string is processed with the following substitutions:
+
+|!Token |!Substituted Value |
+|`DDD` |Day of week in full (eg, "Monday") |
+|`ddd` |Short day of week (eg, "Mon") |
+|`DD` |Day of month |
+|`0DD` |Adds a leading zero |
+|`DDth` |Adds a suffix |
+|`WW` |ISO-8601 week number of year |
+|`0WW` |Adds a leading zero |
+|`MMM` |Month in full (eg, "July") |
+|`mmm` |Short month (eg, "Jul") |
+|`MM` |Month number |
+|`0MM` |Adds leading zero |
+|`YYYY` |Full year |
+|`YY` |Two digit year |
+|`wYYYY` |Full year with respect to week number |
+|`aYYYY` |<<.from-version "5.1.23">> Full year but negative dates are displayed as positive |
+|`wYY` |Two digit year with respect to week number |
+|`{era:BCE||CE}` |<<.from-version "5.1.23">> Displays a different string for years that are negative, zero or positive (see below) |
+|`hh` |Hours |
+|`0hh` |Adds a leading zero |
+|`hh12` |Hours in 12 hour clock |
+|`0hh12` |Hours in 12 hour clock with leading zero |
+|`mm` |Minutes |
+|`0mm` |Minutes with leading zero |
+|`ss` |Seconds |
+|`0ss` |Seconds with leading zero |
+|`XXX` |Milliseconds |
+|`0XXX` |Milliseconds with leading zero |
+|`am` or `pm` |Lower case AM/PM indicator |
+|`AM` or `PM` |Upper case AM/PM indicator |
+|`TZD` |Timezone offset |
+|`\x` |Used to escape a character that would otherwise have special meaning |
+|`[UTC]`|Time-shift the represented date to UTC. Must be at very start of format string|
+
+Note that other text is passed through unchanged, allowing commas, colons or other separators to be used.
+
+The `{era:BCE||CE}` notation can specify different strings for years that are negative, zero or positive. For example `{era:BC|Z|AD}` would display `BC` for negative years, `AD` for positive years, and `Z` for year zero.
+
+! Examples
+
+|!Template |!Output |
+|`DDth MMM YYYY` |16th February 2011 |
+|`DDth MMM \M\M\M YYYY` |16th February MMM 2011 |
+|`DDth mmm YYYY 0hh:0mm:0ss` |16th Feb 2011 11:38:42 |