Learn ChronoKit-FP one concept at a time

This path uses the preferred v1.7 API only. Each step is a complete program under examples/LearningPath/; the documentation links to its source instead of copying a second version. Compile a program with the source-based command from the README, or add the ChronoKit unit through the Lazarus package.

1. Dates and wall clocks#

Run 01-DatesAndWallClocks.lpr.

A TDateTime can represent a calendar date at midnight or an unzoned wall clock with a time of day. Start here for ordinary dates. The program also shows StartOfQuarter(Value) and EndOfQuarter(Value): starts are at midnight and ends are the last millisecond of the quarter.

2. Calendar periods and exact durations#

Run 02-PeriodsAndDurations.lpr.

Use TCalendarPeriod for calendar-relative language such as “one month”. Use TDuration for exact elapsed time such as “24 hours”. Months and years are never silently converted into seconds.

3. Half-open ranges#

Run 03-HalfOpenRanges.lpr.

TDateTimeRange includes its start and excludes its end: [start, end). This makes adjoining bookings unambiguous—09:00 belongs to a 09:00–17:00 workday, while 17:00 does not.

4. Business calendars#

Run 04-BusinessCalendars.lpr.

The default is Monday through Friday. Create a TBusinessCalendar when a holiday or different work week matters. BusinessDaysBetween counts business dates inclusively and ignores input times; reverse the dates to obtain a negative count.

5. Named timezones and DST#

Run 05-NamedTimeZones.lpr.

Timezone conversion begins only when an application has a named source or target zone. ConvertBetweenTimeZones interprets the input clock in the source zone and returns the target clock for the same instant. A TDateTime does not remember a timezone, so retain the target name beside it. UTC works on Windows and Linux; other names are platform-native. A DST gap or overlap in the source clock raises ETimeZoneError rather than guessing.

Choose quickly#

• Need a value type, operation, or error rule? Read the

decision guides.

• Need a task or method name? Search the generated

API reference or the cheat sheet.

• Need more detail about a named-zone error? Read the

timezone contract.