Documentation from inside irb

Ruby
1

Hi,

is there a way to call ri documentation from irb ?
Something like:

shell>irb
irb(main):001:0> help inspect
NameError: undefined method execute' for moduleIRB::ExtendCommand::Help’
from (eval):4:in instance_method' from (eval):4:inhelp’
from (irb):1
from /usr/lib/ruby/1.8/rubygems.rb:1016

2

On Thu, Jul 22, 2010 at 10:08:23PM +0900, Eugen C. wrote:

    from (irb):1
    from /usr/lib/ruby/1.8/rubygems.rb:1016

The wirble gem allows you to use ri from within irb sessions. It adds
various other fancy bits as well, which may or may not be interesting.

Dan

3

wow, it has even tab completion!
thank you Dan!

4

Eugen C. wrote:

wow, it has even tab completion!

that’s easy to get, even without wirble; just:

require 'irb/completion'

–
G.

5

Eugen C. wrote:

Hi,

is there a way to call ri documentation from irb ?

If you just want to access ri within irb then this would do in your
.irbrc:

def help(*args); system(‘ri’, *args); end

If you want a smarter ri, see
eigenclass.org and
Tagaholic - Page Irb Output And Improve Ri With Hirb
.

As for an improvement on irb’s autocompletion, see bond -

Gabriel

6

Eugen C. wrote:

Hi,

is there a way to call ri documentation from irb ?
Something like:

shell>irb
irb(main):001:0> help inspect
NameError: undefined method execute' for moduleIRB::ExtendCommand::Help’
from (eval):4:in instance_method' from (eval):4:inhelp’
from (irb):1
from /usr/lib/ruby/1.8/rubygems.rb:1016

This is a bug in core and “should” work, really…

that being the case, here’s my attempt at it:

$ gem install ri_for
$ irb

require ‘rubygems’
require ‘ri_for’
IO.ri_for :open
sig: Kernel#open arity -1
appears to be a c method
Searching ri for
sig: Kernel#open arity -1
…

ri_for gives you more than just ri–it gives you the source code where
available, which turns out to be quite useful.
Cheers!
-r

7

Thank you!

Gabriel, the only remark is that if I leave method’s name ‘help’ then
upon loading irb a warning is issued:

irb: warn: can’t alias help from irb_help.

If ‘help’ will be renamed to something else, for example, ‘hel’, then
it is possible to call ri help from command line only if its arguments
will be quoted:

irb(main):007:0> hel String
TypeError: can’t convert Class into String
from /home/eugen/.irbrc:3:in system' from /home/eugen/.irbrc:3:inhel’
from (irb):7
from :0
irb(main):008:0> hel ‘String’

=> true