One notation to rule them all
For some time now, I've been working on a Web App framework, and this led me to think about a lot of things, amongst which data typing.
eQual provides a structured way to reference dates allowing to describe and retrieve any date based on the current date, which can be used in Domains for filtering or conditioning visibility.
Date References allow to reference dates relatively to various intervals and dynamically compute dates for a wide range of scenarios by combining methods and parameters.
A Date Reference descriptor is built using the following structure :
date.<origin>(<offset>).<interval>.<method>(<arguments>)
or, in a more explicit notation :
date.{this|prev|next}[(<offset>)].{day|week|month|quarter|semester|year}.{first|last|get(reference:index)}
Attributes and Arguments
1. Origin
| Method | Description | Offset | Possible Values |
|---|---|---|---|
| prev(n) | Previous period with an offset of n intervals | n > 0 |
prev, prev(n)
|
| next(n) | Next period with an offset of n intervals | n > 0 |
next, next(n)
|
| this() | Current period (n=0 by default) | n = 0 |
this, this(0)
|
2. Interval
| Interval | Description |
|---|---|
| day | Day |
| week | Week |
| month | Month |
| quarter | Quarter |
| semester | Semester |
| year | Year |
3. Method
| Method | Description |
|---|---|
| first() | First day of the interval |
| last() | Last day of the interval |
| get() | Get a specific date with arguments |
Tables of Possible Values
Origin
| Method | Possible Values |
|---|---|
prev(<increment>) |
prev, prev(0), prev(n) (n ≥ 0) |
next(<increment>) |
next, next(0), next(n) (n ≥ 0) |
this() |
this, this(0)
|
Interval
| Interval | Description |
|---|---|
day |
Day |
week |
Week |
month |
Month |
quarter |
Quarter |
semester |
Semester |
year |
Year |
Method
Methods can be applied on the chosen interval (except for day, for which the method has no effect).
| Method | Description |
|---|---|
| first() | First day of the interval |
| last() | Last day of the interval |
| get() | Get a specific date |
Arguments for the get() Method
| Argument | Concerned Interval | Possible Values |
|---|---|---|
| day: | month, quarter, semester, year | Month: day:1 to day:31Year: day:1 to day:365
|
| week: | month, quarter, semester, year |
week:1 to week:52 (or week:53) |
| :first | month, quarter, semester, year |
monday:first to sunday:first
|
| :last | month, quarter, semester, year |
monday:last to sunday:last
|
| : | month, quarter, semester, year |
monday:1 to monday:5 (month)monday:1 to monday:14 (quarter)monday:1 to monday:26 (semester)monday:1 to monday:52 (or monday:53) (year) |
Usage Examples
-
today
date.this.day -
Seven days from now
date.next(7).day -
First day of the month 5 months before the current month:
date.prev(5).month.first() -
Last day of the quarter 2 quarters after the current quarter:
date.next(2).quarter.last() -
34th week of the next year:
date.next(1).year.get(week:34) -
First Monday of the semester 3 semesters before the current semester:
date.prev(3).semester.get(monday:first) -
Second Wednesday of the month 4 months after the current month:
date.next(4).month.get(wednesday:2) -
first day of current year:
date.this.year.firstor
date.this.year.get(day:1)
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