time

Time of day, with no date and no time zone, for rules about opening hours, cut-off times and the like. Import it with IMPORT time. Times are kept in 24-hour form; arithmetic wraps around midnight.

Example:

-- Time Example: Wall-clock time operations
IMPORT time

-- Time construction (24-hour format)
DECIDE `office start` IS Time 9 0 0
DECIDE `lunch break` IS Time 12 30
DECIDE `end of day` IS Time 17

#EVAL `office start`   -- 09:00:00
#EVAL `lunch break`    -- 12:30:00
#EVAL `end of day`     -- 17:00:00

-- Time from string (JSON interop) - returns MAYBE TIME
DECIDE `from string` IS Time "14:30:00"
#EVAL `from string`  -- JUST OF (TIME OF 14, 30, 0.0)

-- AM/PM construction
DECIDE `early meeting` IS Time 7 30 am
DECIDE `dinner time` IS Time 7 pm

#EVAL `early meeting`  -- 07:30:00
#EVAL `dinner time`    -- 19:00:00

-- Extracting components
#EVAL `the hour of` `office start`    -- 9
#EVAL `the minute of` `lunch break`   -- 30

-- Time predicates
DECIDE `morning check` IS `office start` `is morning`
DECIDE `afternoon check` IS `lunch break` `is afternoon`
#EVAL `morning check`     -- TRUE
#EVAL `afternoon check`   -- TRUE

-- Time arithmetic (wraps at midnight)
DECIDE `plus two hours` IS `office start` `plus hours` 2
#EVAL `plus two hours`  -- 11:00:00

DECIDE `minus one hour` IS `office start` `minus hours` 1
#EVAL `minus one hour`  -- 08:00:00

-- Time comparisons
DECIDE `start before lunch` IS `office start` LESS THAN `lunch break`
#EVAL `start before lunch`  -- TRUE

DECIDE `start is before lunch` IS `office start` `is before` `lunch break`
DECIDE `lunch is after start` IS `lunch break` `is after` `office start`
#EVAL `start is before lunch`  -- TRUE
#EVAL `lunch is after start`   -- TRUE

#EVAL `the earlier of` `office start` `lunch break`  -- 09:00:00
#EVAL `the later of` `office start` `lunch break`    -- 12:30:00

-- Serial conversion (fraction of day)
#EVAL (Time 12 0 0) `Time to serial`  -- 0.5 (noon = half day)
#EVAL 0.5 `Serial to time`            -- 12:00:00

Constants

Constant	Value
Midnight	00:00:00
Noon	12:00:00
Seconds in a minute, Minutes in an hour	60
Hours in a day	24
Seconds in an hour	3600
Seconds in a day	86400

Meridiem Indicator is an enumeration with the values am and pm.

Building a time

Function	Gives	What it does
Time h m s	TIME	From hours (0 to 23), minutes and seconds
Time h m	TIME	Seconds are 0
Time h	TIME	Minutes and seconds are 0
Time h m s am (or pm)	TIME	12-hour form; also Time h m am and Time h pm
Time text	MAYBE TIME	Reads "HH:MM:SS" or "HH:MM"
Time datetime	TIME	The time part of a DATETIME, ignoring date and time zone
serial `Serial to time`	TIME	From a fraction of a day: 0 is midnight, 0.5 is noon

Reading a time

Function	Gives	What it does
the hour of t	NUMBER	0 to 23
the minute of t	NUMBER	0 to 59
the second of t	NUMBER	0 to 59
t `Time to serial`	NUMBER	The time as a fraction of a day
t `is morning`	BOOLEAN	Before 12:00
t `is afternoon`	BOOLEAN	12:00 to 17:59
t `is evening`	BOOLEAN	18:00 or later
t `is before noon`	BOOLEAN	Before 12:00
t `is after noon`	BOOLEAN	12:00 or later

Moving a time

Each of these wraps around midnight: (Time 23 0 0) `plus hours` 2 is 01:00. Put a time built with Time in parentheses, as here, before a word written after it.

Function	Gives
t `plus hours` n, t `minus hours` n	TIME
t `plus minutes` n, t `minus minutes` n	TIME
t `plus seconds` n, t `minus seconds` n	TIME

Comparing times

• =, <, <=, >, >= and their word forms compare two times.
• t1 MINUS t2 is the difference in seconds.
• t1 `is before` t2 and t1 `is after` t2 read as sentences.
• `the earlier of` t1 t2 and `the later of` t1 t2 pick one of two times.