accessing ruby standard library documentation locally

Question

I'm just getting into Ruby - one of the things I'm having a little trouble letting go of is Intellisense / code completion, so if I don't have that I really need to have the API close to hand at all times. I made the discovery last week of:

gem server

which starts a server which lets you check out the documentation for all of your installed gems. Is there an equivalent to this which allows you to browse the standard libraries instead of the gems?

Using Linux/Ruby 1.8.7.

Answer 1

In your terminal, you can use ri to print specific parts of the documentation. (Note that if you're using RVM to manage your ruby installation(s), you may need to run rvm docs generate to avoid getting "Nothing known about...." responses)

For example:

> ri Array#drop

would output:

------------------------------------------------------------- Array#drop
     ary.drop(n)               => array
------------------------------------------------------------------------
     Drops first n elements from _ary_, and returns rest elements in an
     array.

        a = [1, 2, 3, 4, 5, 0]
        a.drop(3)             # => [4, 5, 0]

Answer 2

Several options:

• Local, searchable Rails and Ruby docs (options to add other docs like haml, rspec, rack, etc., but not quite up-to-date)
• Create from source
• ri
• ... and a million tools to generate snazzy docs from Ruby source, including...
• doc, which generates local searchable docs of whatever you tell it to; I'm digging it

Answer 3

Devdocs does the job

• it works (also) offline
• it is not limited to the ruby doc ;)

Clone the repo from github:

git clone git@github.com:Thibaut/devdocs.git
cd devdocs

Install dependencies:

gem install bundler
bundle install

download the docs:

thor docs:download --all

Run it:

rackup

It's accessible by default at http://localhost:9292