Skip to content
This repository


Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP

Supercharged method introspection in IRB

tree: cf369c5e3e

Fetching latest commit…


Cannot retrieve the latest commit at this time

Octocat-spinner-32 ext
Octocat-spinner-32 lib
Octocat-spinner-32 spec
Octocat-spinner-32 .autotest Hi.
Octocat-spinner-32 .gitignore
Octocat-spinner-32 CHANGELOG
Octocat-spinner-32 Gemfile
Octocat-spinner-32 History.txt Update history.
Octocat-spinner-32 LICENSE Add LICENSE.
Octocat-spinner-32 README.markdown
Octocat-spinner-32 Rakefile
Octocat-spinner-32 looksee.gemspec


A tool for illustrating the ancestry and method lookup path of objects. Great for exploring unfamiliar codebases!


Install me:

gem install looksee

Pop this in your .irbrc:

require 'looksee'

Now each object has a method ls, which shows you all its methods.

irb> [].ls
 => BasicObject
  !   __send__    instance_eval   singleton_method_added    
  !=  equal?      instance_exec   singleton_method_removed  
  ==  initialize  method_missing  singleton_method_undefined
  !~                       freeze                      puts                    
  <=>                      frozen?                     raise                   
  ===                      gem                         rand                    
  =~                       gem_original_require        readline                
  Array                    gets                        readlines               
  Complex                  global_variables            remove_instance_variable
  Float                    hash                        require                 
  Integer                  initialize_clone            require_relative        
  Rational                 initialize_copy             respond_to?             
  String                   initialize_dup              respond_to_missing?     
  URI                      inspect                     select                  
  __callee__               instance_of?                send                    
  __id__                   instance_variable_defined?  set_trace_func          
  __method__               instance_variable_get       singleton_class         
  `                        instance_variable_set       singleton_methods       
  abort                    instance_variables          sleep                   
  at_exit                  is_a?                       spawn                   
  autoload                 iterator?                   sprintf                 
  autoload?                kind_of?                    srand                   
  binding                  lambda                      syscall                 
  block_given?             load                        system                  
  caller                   local_variables             taint                   
  catch                    loop                        tainted?                
  class                    method                      tap                     
  clone                    methods                     test                    
  define_singleton_method  nil?                        throw                   
  display                  object_id                   to_enum                 
  dup                      open                        to_s                    
  enum_for                 p                           trace_var               
  eql?                     print                       trap                    
  eval                     printf                      trust                   
  exec                     private_methods             untaint                 
  exit                     proc                        untrace_var             
  exit!                    protected_methods           untrust                 
  extend                   public_method               untrusted?              
  fail                     public_methods              warn                    
  fork                     public_send                 y                       
  format                   putc                      
  edit  ls
  default_src_encoding  oauth            taguri   to_yaml_properties
  in?                   patch            taguri=  to_yaml_style     
  irb_binding           singleton_class  timeout
  load_if_available     syck_to_yaml     to_yaml
  all?            drop_while        first     min           select      
  any?            each_cons         flat_map  min_by        slice_before
  by              each_entry        grep      minmax        sort        
  chunk           each_slice        group_by  minmax_by     sort_by     
  collect         each_with_index   include?  none?         take        
  collect_concat  each_with_object  inject    one?          take_while  
  count           entries           map       partition     to_a        
  cycle           find              max       reduce        to_set      
  detect          find_all          max_by    reject        zip         
  drop            find_index        member?   reverse_each
  &            drop_while       map!                  size           
  *            each             pack                  slice          
  +            each_index       permutation           slice!         
  -            empty?           pop                   sort           
  <<           eql?             product               sort!          
  <=>          fetch            push                  sort_by!       
  ==           fill             rassoc                taguri         
  []           find_index       reject                taguri=        
  []=          first            reject!               take           
  assoc        flatten          repeated_combination  take_while     
  at           flatten!         repeated_permutation  to_a           
  clear        frozen?          replace               to_ary         
  collect      hash             reverse               to_s           
  collect!     include?         reverse!              to_yaml        
  combination  index            reverse_each          transpose      
  compact      initialize       rindex                uniq           
  compact!     initialize_copy  rotate                uniq!          
  concat       insert           rotate!               unshift        
  count        inspect          sample                values_at      
  cycle        join             select                yaml_initialize
  delete       keep_if          select!               zip            
  delete_at    last             shift                 |              
  delete_if    length           shuffle             
  drop         map              shuffle!             

Methods are colored according to whether they're public, protected, private, undefined (using Module#undef_method), or overridden.

You can hide, say, private methods like this:

irb> [].ls :noprivate

Or filter the list by Regexp:

irb> [].ls /^to_/
 => BasicObject
  to_enum  to_s
  to_yaml  to_yaml_properties  to_yaml_style
  to_a  to_set
  to_a  to_ary  to_s  to_yaml 

And if you want to know more about any of those methods, Looksee can take you straight to the source in your editor:

> [].edit('to_set')

By default, this uses vi; customize it like this:

# %f = file, %l = line number
Looksee.editor = "mate -l%l %f"

See more in the quick reference:




Looksee works with:

  • MRI/REE (>= 1.8.6)
  • JRuby (>= 1.5.6)
  • Rubinius (>= 1.2.1)


  • Bug reports
  • Source
  • Patches: Fork on Github, send pull request.
    • Include tests where practical.
    • Leave the version alone, or bump it in a separate commit.


Copyright (c) George Ogata. See LICENSE for details.

Something went wrong with that request. Please try again.