Lookup for Ruby & Rails api in the terminal
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Lazy Man's ri (lookup)



gem install lookup

Example usage:

This has changed since the pre-1.0 versions. From 1.0 onwards you sometimes have to specify an API that you wish to search.

  • lookup v2.3.8 ActiveRecord::Base#new (returns a single method from the Rails 2.3.8 API, since the method name is right)
  • lookup v3.0.0 ActiveRecord::Base#destroy (returns two methods from the Rails 3.0.0 API, since there's two methods with that name)
  • lookup v2.3.8 ActiveRecord::Base#destro (returns three methods, uses methods beginning with "destro")
  • lookup v2.3.8 ActiveRecord::Base#d (tells you to be more specific, because it can't open 35 tabs at once)
  • lookup v2.3.8 ActiveRecord::Base (returns a single consant)
  • lookup v2.3.8 av::Base ("av" maps to ActionView, so returns ActionView::Base constant)

And for those of you who are Ruby inclined:

  • lookup 1.8 Array#join (Returns a single method from the Ruby 1.8.7 API)
  • lookup 1.9 Array#join (Returns a single method from the Ruby 1.9 API)

Or if you want to to look up for your current version of Ruby, simply:

  • lookup Array#join (Returns a single method from either Ruby 1.8 or Ruby 1.9. Other implementations not yet supported.)


It also takes options:

  • -c or --clear will delete the database and update the api again. This can take a minute or two.
  • -t or --text is useful for when you don't want lookup to spam tabs into your browser willy-nilly.


Lookup (as of 1.0) comes with a configuration file at ~/.lookup/config which you can use to alter the APIs which lookup looks through. The name Lookup uses to determine what API you want is the key for the info hash. The name in the info hash serves no real importance other than for than "you fail at lookup" APINotFound error messages, where as the URL must point to the exact directory where the _fr_method_index.html file is located.

How it finds them

  1. Finds the specified API and uses it to scope future calls.
  2. Checks if there's constants/methods with that exact name.
  3. Checks if there's constants/methods with names beginning with that name.
  4. Does a "fuzzy match" splitting the name and getting anything containing those letters in that order.
  5. Opens your browser if you're running a DECENT_OPERATING_SYSTEM (may add support for things other than Mac later on)
  6. ???
  7. Profit