The Calendar package has new commands for parsing and formatting Date and Time objects.

Use the Calendar:-Format command or the Calendar:-VariantFormat command to format a Date or UTC Time object as a string. You can do this in a locale-sensitive way by using the locale option.

Codes for formatting and parsing are specified according to the Unicode Technical Standard #35, "Unicode Locale Data Markup Language (LDML)", Part 4 (Dates).

with( Calendar ):

Format( Today() );

$''2025-03-24T10:27:34\; UTC''$

Format( Today(), 'locale' = "fr" );

$''2025-03-24T10:27:34\; UTC''$

Format( Today(), "yyyy.MM.dd G 'at' HH:mm:ss zzz" );

$''2025.03.24\; AD\; at\; 10:27:34\; UTC''$

Format( Today(), "yyyy.MM.dd G 'um' HH:mm:ss zzz", 'locale' = "de" );

$''2025.03.24\; n.\; Chr.\; um\; 10:27:34\; UTC''$

Format( Now( SystemUTCClock ), "K:mm a, z", 'locale' = "ja" );

$''10:27\; 午前,\; UTC''$

Format( Now( SystemUTCClock ), "hh 'o''clock' a, zzzz" );

$''10\; o\text{'}clock\; AM,\; Coordinated\; Universal\; Time''$

You can use a different (printf-like) formatting string by using the command VariantFormat.

Unlike the similar command FormatTime in the StringTools package, the Calendar:-VariantFormat command supports the locale option, allowing you to format dates and times in a locale-sensitive way. Moreover, the Calendar package commands work directly with Date and UTC Time objects.

VariantFormat( Today(), "%c" );

$''Mon\; Mar\; 24\; 10:27:34\; 2025''$

VariantFormat( Today(), "%c", 'locale' = "id" );

$''Sen\; Mar\; 24\; 10:27:34\; 2025''$

fmt := "EEEE, MMMM dd, yyyy GG, hh:mm:ss a":

DocumentTools:-Tabulate( map( loc -> Format( Today(), fmt, ':-locale' = loc ), << "en", "fr", "de" > | < "ks", "ja", "ko" >> ) ):

As for formatting, there are new commands to parse dates in strings. These are Parse and VariantParse, corresponding to Format and VariantFormat, respectively.

Both Parse and VariantParse support the locale option.

s := Format( Today(), "EEEE, MMMM dd, yyyy GG, hh:mm:ss a", 'locale' = "id" );

$s≔''Senin,\; Maret\; 24,\; 2025\; M,\; 10:27:34\; AM''$

Parse( s, "EEEE, MMMM dd, yyyy GG, hh:mm:ss a", 'locale' = "id" );

$\mathrm{<Date:\; 2025-03-24T10:27:34\; GMT>}$

s := VariantFormat( Today(), "%c", 'locale' = "de" );

$s≔''Mo.\; März\; 24\; 10:27:35\; 2025''$

VariantParse( s, "%c", 'locale' = "de" );

$\mathrm{<Date:\; 2025-03-24T10:27:35\; GMT>}$