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Chronic

Chronic is a natural language date/time parser written in pure Ruby. See below for the wide variety of formats Chronic will parse.

Installation

$ gem install chronic

Usage

require 'chronic'

Time.now   #=> Sun Aug 27 23:18:25 PDT 2006

Chronic.parse('tomorrow')
  #=> Mon Aug 28 12:00:00 PDT 2006

Chronic.parse('monday', :context => :past)
  #=> Mon Aug 21 12:00:00 PDT 2006

Chronic.parse('this tuesday 5:00')
  #=> Tue Aug 29 17:00:00 PDT 2006

Chronic.parse('this tuesday 5:00', :ambiguous_time_range => :none)
  #=> Tue Aug 29 05:00:00 PDT 2006

Chronic.parse('may 27th', :now => Time.local(2000, 1, 1))
  #=> Sat May 27 12:00:00 PDT 2000

Chronic.parse('may 27th', :guess => false)
  #=> Sun May 27 00:00:00 PDT 2007..Mon May 28 00:00:00 PDT 2007

Chronic.parse('6/4/2012', :endian_precedence => :little)
  #=> Fri Apr 06 00:00:00 PDT 2012

Chronic.parse('INVALID DATE')
  #=> nil

If the parser can find a date or time, either a Time or Chronic::Span will be returned (depending on the value of :guess). If no date or time can be found, nil will be returned.

See Chronic.parse for detailed usage instructions.

Examples

Chronic can parse a huge variety of date and time formats. Following is a small sample of strings that will be properly parsed. Parsing is case insensitive and will handle common abbreviations and misspellings.

Simple

Complex

Specific Dates

Specific Times (many of the above with an added time)

Time Zones

Chronic allows you to set which Time class to use when constructing times. By default, the built in Ruby time class creates times in your system's local time zone. You can set this to something like ActiveSupport's TimeZone class to get full time zone support.

>> Time.zone = "UTC"
>> Chronic.time_class = Time.zone
>> Chronic.parse("June 15 2006 at 5:45 AM")
=> Thu, 15 Jun 2006 05:45:00 UTC +00:00

Limitations

Chronic uses Ruby's built in Time class for all time storage and computation. Because of this, only times that the Time class can handle will be properly parsed. Parsing for times outside of this range will simply return nil. Support for a wider range of times is planned for a future release.

Contribute

If you'd like to hack on Chronic, start by forking the repo on GitHub:

https://github.com/mojombo/chronic

The best way to get your changes merged back into core is as follows:

  1. Clone down your fork
  2. Create a thoughtfully named topic branch to contain your change
  3. Install the development dependencies by running bundle install
  4. Hack away
  5. Add tests and make sure everything still passes by running bundle exec rake
  6. Ensure your tests pass in multiple timezones. ie TZ=utc bundle exec rake TZ=BST bundle exec rake
  7. If you are adding new functionality, document it in the README
  8. Do not change the version number, we will do that on our end
  9. If necessary, rebase your commits into logical chunks, without errors
  10. Push the branch up to GitHub
  11. Send a pull request for your branch