GNU Smalltalk User's Guide: Date

6.52 Date

Defined in namespace Smalltalk

Category: Language-Data types

My instances represent dates. My base date is defined to be Jan 1, 1901. I provide methods for instance creation (including via "symbolic" dates, such as "Date newDay: 14 month: #Feb year: 1990".

PLEASE BE WARNED -- use this class only for dates after 1582 AD; that's the beginning of the epoch. Dates before 1582 will not be correctly printed. In addition, since ten days were lost from October 5 through October 15, operations between a Gregorian date (after 15-Oct-1582) and a Julian date (before 5-Oct-1582) will give incorrect results; or, 4-Oct-1582 + 2 days will yield 6-Oct-1582 (a non-existent day!), not 16-Oct-1582.

In fact, if you pass a year < 1582 to a method like #newDay:month:year: it will assume that it is a two-digit year (e.g. 90=1990, 1000=2900). The only way to create Julian calendar dates is with the #fromDays: instance creation method.

6.52.1 Date class: basic    (class)

6.52.2 Date class: instance creation (ANSI)    (class)

6.52.3 Date class: instance creation (Blue Book)    (class)

6.52.4 Date: basic    (instance)

6.52.5 Date: compatibility (non-ANSI)    (instance)

6.52.6 Date: date computations    (instance)

6.52.7 Date: printing    (instance)

6.52.8 Date: storing    (instance)

6.52.9 Date: testing    (instance)

6.52.1 Date class: basic

abbreviationOfDay: dayIndex: Answer the abbreviated name of the day of week corresponding to the given index
dayOfWeek: dayName: Answer the index of the day of week corresponding to the given name
daysInMonth: monthName forYear: yearInteger: Answer the number of days in the given (named) month for the given year
daysInYear: i: Answer the number of days in the given year
indexOfMonth: monthName: Answer the index of the month corresponding to the given name
initDayNameDict: Initialize the DayNameDict to the names of the days
initialize: Initialize the receiver
initMonthNameDict: Initialize the MonthNameDict to the names of the months
nameOfDay: dayIndex: Answer the name of the day of week corresponding to the given index
nameOfMonth: monthIndex: Answer the name of the month corresponding to the given index
shortNameOfMonth: monthIndex: Answer the name of the month corresponding to the given index

6.52.2 Date class: instance creation (ANSI)

year: y day: d hour: h minute: min second: s: Answer a Date denoting the d-th day of the given year
year: y month: m day: d hour: h minute: min second: s: Answer a Date denoting the d-th day of the given (as a number) month and year

6.52.3 Date class: instance creation (Blue Book)

dateAndTimeNow: Answer an array containing the current date and time
fromDays: dayCount: Answer a Date denoting dayCount days past 1/1/1901
fromJulian: jd: Answer a Date denoting the jd-th day in the astronomical Julian calendar.
fromSeconds: time: Answer a Date denoting the date time seconds past Jan 1st, 1901
newDay: day month: monthName year: yearInteger: Answer a Date denoting the dayCount day of the given (named) month and year
newDay: day monthIndex: monthIndex year: yearInteger: Answer a Date denoting the dayCount day of the given (as a number) month and year
newDay: dayCount year: yearInteger: Answer a Date denoting the dayCount day of the yearInteger year
readFrom: aStream: Parse an instance of the receiver from aStream
today: Answer a Date denoting the current date in local time
utcDateAndTimeNow: Answer an array containing the current date and time in Coordinated Universal Time (UTC)
utcToday: Answer a Date denoting the current date in Coordinated Universal Time (UTC)

6.52.4 Date: basic

addDays: dayCount: Answer a new Date pointing dayCount past the receiver
subtractDate: aDate: Answer the number of days between aDate and the receiver (negative if the receiver is before aDate)
subtractDays: dayCount: Answer a new Date pointing dayCount before the receiver

6.52.5 Date: compatibility (non-ANSI)

day: Answer the day represented by the receiver
dayName: Answer the day of week of the receiver as a Symbol
shortMonthName: Answer the abbreviated name of the month represented by the receiver

6.52.6 Date: date computations

asSeconds: Answer the date as the number of seconds from 1/1/1901.
dayOfMonth: Answer the day represented by the receiver (same as #day)
dayOfWeek: Answer the day of week of the receiver. 1 = Monday, 7 = Sunday
dayOfWeekAbbreviation: Answer the day of week of the receiver as a Symbol
dayOfWeekName: Answer the day of week of the receiver as a Symbol
dayOfYear: Answer the days passed since 31/12 of last year; e.g. New Year's Day is 1
daysFromBaseDay: Answer the days passed since 1/1/1901
daysInMonth: Answer the days in the month represented by the receiver
daysInYear: Answer the days in the year represented by the receiver
daysLeftInMonth: Answer the days to the end of the month represented by the receiver
daysLeftInYear: Answer the days to the end of the year represented by the receiver
firstDayOfMonth: Answer a Date representing the first day of the month represented by the receiver
isLeapYear: Answer whether the receiver refers to a date in a leap year.
lastDayOfMonth: Answer a Date representing the last day of the month represented by the receiver
month: Answer the month represented by the receiver
monthAbbreviation: Answer the abbreviated name of the month represented by the receiver
monthName: Answer the name of the month represented by the receiver
year: Answer the year represented by the receiver

6.52.7 Date: printing

printOn: aStream: Print a representation for the receiver on aStream

6.52.8 Date: storing

storeOn: aStream: Store on aStream Smalltalk code compiling to the receiver

6.52.9 Date: testing

< aDate: Answer whether the receiver indicates a date preceding aDate
= aDate: Answer whether the receiver indicates the same date as aDate
hash: Answer an hash value for the receievr

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