Schedule Query Langauge

SHEQL is a schema less solution to the problem of storing repeated events in a calendar. It is inspired by CSS selectors.

Features

1. A Far More powerful and customizable logic for repetition can be written.
2. A Schemaless Architecture.
3. A single change is required to update repeated events.
4. Platform independent.

Learn more about the syntax.

Elements

They are analogous to tag names in HTML.

1. y - Representing years

2. m - Representing months

3. w - Representing weeks

4. d - Representing days

Element Properties

Properties are like css classes applied on tags. Each tag has its own set of classes (properties as we call them here).

Years

1. 365d, 366d - Filters all the years in the given range which have 365 days or 366 days (AKA leap year)

2. 52w - Filters all the years based on the total number of weeks that fall in that year. First day of the week is Sunday be default.

3. 2015 - Filter based on the year value.

Months

1. 31d, 30d, 29d, 28d - Filters all the the months based on the total days that are in that month.

2. 4w, 5w - Filter out months based on the number of weeks in it.

3. jan ... dec - Filtering based on the month name.

Weeks

1. 7d, 4d - Filter outs weeks based on the total number of days in it.

Days

1. 21 - Filter based on the date value.

2. sat, sun, ... fri - Filter days on the day of the week.

Filters

Filters can be applied on any type of element. They can use the element's properties also.

Dot notation

Use it to filter out elements that have the specified property.

y.365d /*Selects non-leap years*/
m.jan  /*Select the month January*/

exclamation notation

Use it to filter out elements that do NOT have the specified property.

m!jan /*all months except january*/

nth element

Use it to filter out the nth element

d:n[x+3] /*All days except the first 2*/
d:n[3]   /*3 day only*/
d:n[2x]  /*All alternate days*/

lth element

Use it to filter out the nth element for the last element.

d:l[x+3] /*All days except the last 2*/

Examples

Yearly repeated on the 45th day

y d:n[45]

Monthly 1st sat

m d.sat:n[1]

Monthly 1st day if it's a sat

m d:n[1].sat

monthly last sat

m d.sat:l[1]

monthly second last sat

m d.sat:l[2]

monthly all sat

m d.sat

every 3rd months 2nd sat

m:n[3x] d.sat:n[2]

every 1st of every month

m d:n[1]

Every alternate month second week, first mondays

m:n[2x] w:n[2] d.mon

Every alternate month second monday

m:n[2x] d.mon:n[2]

100th day of each year

y d:n[100]

14th Feb every yr

y m:n[1] d:n[14]
y m.feb d:n[14]
y m.feb d.14

Every 20th day

d:n[20x]

every mar-dec weekdays

y m:n[-x+3] d:n[x+1]:n[-x+1]

every day in jan except fridays

m.jan d!fri

every alternate month's first and third saturday

m:n[2x] d.sat:l[x+2]:n[2x+1]

How to use from cli

1. run npm install sheql -g.
2. Example - get all the tuesdays of the year, except if they fall on the last day of the month

   sheql 'm.sep d:l[x+2].tue'
   

3. To use it as a package dependency, install it locally and use require 'sheql'.

Using as a dependency

var sheql = require('sheql');
var startDate = new Date(2010, 1,10);
var endDate = new Date(2110, 4,15);
var startDayOfWeek = 1; //Monday
sheql.getDates('m.sep d:l[x+2].tue', startDate, endDate, startDayOfWeek);