From: Josh Cheek <josh.cheek@...>
Date: 2011-08-01T04:50:30+09:00
Subject: Re: Documentation in Ruby

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On Sun, Jul 31, 2011 at 3:28 AM, amir e. <aef1370@gmail.com> wrote:

> Hi
> I have a problem with Ruby Reference. How can I see all the methods of a
> class? for example from where I know that array has a method that its
> name is "detect" ?
>
> thanks
>
> --
> Posted via http://www.ruby-forum.com/.
>
>
There are several useful methods:
obj.methods # public methods
obj.public_methods
obj.private_methods
obj.protected_methods
obj.singleton_methods
Class.instance_methods
Class.instance_methods(false) # no inherited methods


Note that array arithmetic can sometimes be useful, ie:
module M
  def m
  end
end
class C
  include M
  def c
  end
end
C.instance_methods - Object.new.methods # => [:c, :m]



Also note that grepping can sometimes be useful, ie:
Array.new.methods.grep(/index/) # => [:each_index, :find_index, :index,
:rindex, :each_with_index]



Also, if you're doing this in IRB, consider trying Pry, which offers the
`ls` command that makes this sort of thing less tedious. I give a few
examples of it in my screencast @ http://vimeo.com/26391171 here's all the
options it supports:

pry(main)> ls -h
Usage: ls [OPTIONS] [VAR]
List information about VAR (the current context by default).
Shows local and instance variables by default.
--
    -g, --globals                    Display global variables.
    -c, --constants                  Display constants.
    -l, --locals                     Display locals.
    -i, --ivars                      Display instance variables.
    -k, --class-vars                 Display class variables.
    -m, --methods                    Display methods (public methods by
default).
    -M, --instance-methods           Display instance methods (only relevant
to classes and modules).
    -P, --public                     Display public methods (with -m).
    -r, --protected                  Display protected methods (with -m).
    -p, --private                    Display private methods (with -m).
    -j, --just-singletons            Display just the singleton methods
(with -m).
    -s, --super                      Include superclass entries excluding
Object (relevant to constant and methods options).
    -e, --everything                 Include superclass entries including
Object (must be combined with -s switch).
    -a, --all                        Display all types of entries.
    -v, --verbose                    Verbose ouput.
    -f, --flood                      Do not use a pager to view text longer
than one screen.
        --grep REG                   Regular expression to be used.
    -h, --help                       Show this message.



On Sun, Jul 31, 2011 at 7:24 AM, 7stud -- <bbxx789_05ss@yahoo.com> wrote:

>
> All the methods that an object can call come from several sources:
>
> all it's parent classes
>
>
Presumably you mean classes inherited from its class and singleton class?


> modules its parent class's include
>
>
Presumably you mean classes its singleton class includes?

If one knows enough internals, the list can be made elegant: its class and
classes its class inherits from. But for that, you have to understand how
Ruby lies to you in order to have singleton classes and look like multiple
inheritance. If anyone is interested in that, there is a fantastic blog
entry that covers most of it @
http://carboni.ca/blog/p/Modules-How-Do-They-Work.

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