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EndOfAWeek

Function EndOfAWeek(const AYear, AWeekOfYear: Word;
  const ADayOfWeek: Word): TDateTime

Example​

procedure ScriptEvent(var Value: variant);
begin
  Value := EndOfAWeek(2026, 1, 7); // Sunday 4 January 2026, 23:59:59.999
end;

Usage​

EndOfAWeek returns the final millisecond of a chosen weekday in a supplied ISO week-numbering year and week.

Parameters

NameTypeDescription
AYearWord, constISO week-numbering year 1..9999.
AWeekOfYearWord, constISO week number valid for AYear.
ADayOfWeekWord, constMonday 1 through Sunday 7; required by the Velox declaration.

Returns

The final millisecond of the chosen ISO weekday. Near New Year, the result's calendar year can differ from AYear.

Errors

Invalid ISO year/week/day fields raise EConvertError through EncodeDateWeek.

Additional Technical Info​

EndOfAWeek encodes one weekday in an ISO week and sets its time to 23:59:59.999. Despite its name, the result is the end of the selected day; it is the end of the ISO week only when ADayOfWeek is Sunday (7).

The example is fictional, deterministic and source-reviewed. It was not executed by the documentation workflow.

Implementation

The DateUtils import binds directly to Delphi 37.0 System.DateUtils.EndOfAWeek. It calls EncodeDateWeek(AYear, AWeekOfYear, ADayOfWeek) and then EndOfTheDay on the result.

Edge cases and quirks

  • The upstream Delphi declaration defaults ADayOfWeek to Sunday, which makes a two-argument Delphi call mean the week end. The generated Velox script declaration exposes no default and requires the third argument.
  • Passing Monday (1) returns Monday's final millisecond, not Sunday. Use 7 when the boundary must be the end of the ISO week.
  • AYear is the ISO week year and can differ from the calendar year of the returned date.
  • Week 53 is accepted only for ISO years that contain it.
  • The result is timezone-neutral and millisecond-resolution.

Side effects

None.

Performance and concurrency

Constant bounded calendar arithmetic with no shared state.

Related entries

  • EndOfTheWeek always returns the Sunday ending the week that contains an existing value.
  • EncodeDateWeek returns the selected day's midnight.

External references

Created 2026-07-15