This module brings together some useful tools when working
with dates (the prefix nu stands for Nim utils).
Nim +2.0.0
Nim standard library only.
Install nudates using nimble:
nimble install nudates
or add a dependency to the .nimble file of your project:
requires "nudates >= 0.1.0"
and start using it.
We will limit ourselves here to a few examples but the user is invited to browse the module documentation to have an overview of all the functionalities made available.
In the standard library, dates can be handled with the DateTime
type of the times module. As its name suggests, this type
actually allows us to manage dates and times at the same time.
But sometimes intraday information (hours, minutes, seconds, etc.)
is not important to us.
For example, dt1 = dateTime(2025, mDec, 25, 2) and
dt2 = dateTime(2025, mDec, 25, 4) both correspond to Christmas Day
of the year 2025, while dt1 == dt2 is false because the hours are
not the same (resp. 2 and 4). Consequently we have defined new
comparison operators (~==, !~==, <<, <<~==, >>, >>~==)
which do the same job as the original comparison operators of the
DateTime type (resp. ==, !=, <, <=, >, >=), but which
do not take intraday information (hours, minutes, seconds, etc.) into
account in their processing (the reader will find a justification of
the notations adopted in the respective documentation of these operators).
let dt1 = dateTime(2011, mSep, 18, 2) # 2011-09-18T:02:00:00
let dt2 = dateTime(2011, mSep, 18, 5) # 2011-09-18T:05:00:00
let dt3 = dateTime(2011, mOct, 18, 1) # 2011-10-18T:01:00:00
doAssert: dt1 == dt1 and dt1 ~== dt1
doAssert: dt1 != dt2 and dt1 ~== dt2
doAssert: dt1 < dt3 and dt1 << dt3
doAssert: dt3 > dt1 and dt3 >> dt1It is obviously possible to do without the tools made available here but the alternatives that one might think of spontaneously have certain obvious disadvantages. Let's give examples.
import times
# The two `date` procedures below allow you to create `DateTime`
# objects with default values for intraday information.
proc date*(year: int; month: Month; monthday: MonthdayRange;
zone: Timezone = local()): DateTime =
dateTime(year, month, monthday, zone = zone)
proc date*(dt: DateTime): DateTime =
dateTime(dt.year, dt.month, dt.monthday, zone = dt.timeZone)
## we can repeat some of the comparisons made in the previous section
let dt1 = dateTime(2011, mSep, 18, 2) # 2011-09-18T:02:00:00
let dt2 = dateTime(2011, mSep, 18, 5) # 2011-09-18T:05:00:00
doAssert: dt1 != dt2 and dt1.date == dt2.date
# We exclusively used the operators of the `times` module. But
# there is a price to pay: the number of additional objects to
# create through the `dt1.date` and `dt2.date` instructions.
#
# To avoid the creation of additional objects through `date` procs,
# we can impose ourselves to systematically create `DateTime` objects
# without intra-day information. But this means depriving oneself
# de facto information that could be useful for other modules.The choices made in the nudates module should therefore be clear
to the user. We are not changing anything about how we create DateTime
objects with or without intraday information. But we provide the user
with new comparison operators which do not take this intra-day information
into account.