• NAME
• INSTALLATION
• SYNOPSIS
• DESCRIPTION
  • Warning
• API
  • MethodFinder.find
  • Object#find_method
    • Ignorelists
  • MethodFinder.find_classes_and_modules
  • MethodFinder.find_in_class_or_module
• TROUBLESHOOTING
• DEVELOPMENT
• CONTRIBUTING
• SEE ALSO
  • Gems
  • Misc
• VERSION
• AUTHOR
• LICENSE

MethodFinder - a Smalltalk-like Method Finder for Ruby

$ gem install methodfinder

Welcome to IRB. # or Pry

>> 'Hello, world!'.find_method('HELLO, WORLD!')
#=> ["String#upcase", "String#upcase!"]

>> %w[a b c].find_method('c')
#=> ["Array#last", "Array#max", "Array#pop"]

>> %w[a b c].find_method { |it| it.unknown(2); it == %w[c] }
#=> ["Array#shift"]

A Smalltalk-like Method Finder for Ruby for use in your ~/.irbrc or ~/.pryrc.

This project was originally inspired by Smalltalk's Method Finder, but additional features have been added over time.

Common sense not included!

While this gem should generally be safe to use, it's still better to be safe than sorry, so use this with caution and maybe not on production data.

This was initially written for the students of the core Ruby course on RubyLearning, so it's generally not tested in a Rails console, just plain IRB/Pry.

Provided with a receiver, the desired result and possibly some arguments, MethodFinder.find will list all methods that produce the given result when called on the receiver with the provided arguments.

MethodFinder.find(10, 1, 3)
#=> ["Fixnum#%", "Fixnum#<=>", "Fixnum#>>", "Fixnum#[]", "Integer#gcd", "Fixnum#modulo", "Numeric#remainder"]
MethodFinder.find("abc", "ABC")
#=> ["String#swapcase", "String#swapcase!", "String#upcase", "String#upcase!"]
MethodFinder.find(10, 100, 2)
#=> ["Fixnum#**"]
MethodFinder.find(['a', 'b', 'c'], ['A', 'B', 'C']) { |x| x.upcase }
#=> ["Array#collect", "Array#collect!", "Enumerable#collect_concat", "Enumerable#flat_map", "Array#map", "Array#map!"]

This gem also adds Object#find_method, which besides offering an alternative interface to pretty much the same functionality as MethodFinder.find, also allows you to test for state other than the return value of the method.

%w[a b c].find_method { |a| a.unknown(1) ; a == %w[a c] }
#=> ["Array#delete_at", "Array#slice!"]
10.find_method { |n| n.unknown(3) == 1 }
#=> ["Fixnum#%", "Fixnum#<=>", "Fixnum#>>", "Fixnum#[]", "Integer#gcd", "Fixnum#modulo", "Numeric#remainder"]

Inside find_method's block, the receiver is available as block argument and the special method unknown is used as a placeholder for the desired method.

You can also call find_method without passing a block. This is the same as calling MethodFinder.find.

10.find_method(1, 3)
#=> ["Fixnum#%", "Fixnum#<=>", "Fixnum#>>", "Fixnum#[]", "Integer#gcd", "Fixnum#modulo", "Numeric#remainder"]

You can exclude methods from being tried by editing the hashes MethodFinder::INSTANCE_METHOD_IGNORELIST and MethodFinder::CLASS_METHOD_IGNORELIST. Both use the class/module as key and an array of method names as values (note that class, module and method names have to be symbols).

For example, to ignore the instance method shutdown of Object, you would do

MethodFinder::INSTANCE_METHOD_IGNORELIST[:Object] << :shutdown

This might come in handy when using MethodFinder together with other gems as such as interactive_editor.

A simple method to return all currently defined modules and classes.

MethodFinder.find_classes_and_modules
#=> [ArgumentError, Array, BasicObject, Bignum ... ZeroDivisionError]

Searches for a given name within a class. The first parameter can either be a class object, a symbol or a string whereas the optional second parameter can be a string or a regular expression:

MethodFinder.find_in_class_or_module('Array', 'shuff')
#=> [:shuffle, :shuffle!]
MethodFinder.find_in_class_or_module(Float, /^to/)
#=> [:to_f, :to_i, :to_int, :to_r, :to_s]

If the second parameter is omitted, all methods of the class or module will be returned.

MethodFinder.find_in_class_or_module(Math)
#=> [:acos, :acosh, :asin ... :tanh]

If the METHOD_FINDER_DEBUG environment variable is set, the name of each candidate method is printed to STDERR before it is invoked. This can be useful to identify (and consequently ignore) misbehaving methods.

It can be set on the command line e.g.:

$ METHOD_FINDER_DEBUG=1 irb

Or you can toggle it inside IRB/Pry:

>> MethodFinder.toggle_debug!

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Development happens primarily on Sourcehut where you can file bugs, discuss on the mailing list or send patches.

If you really have to you can also contribute via https://github.com/citizen428/methodfinder, but I really prefer Sourcehut.

• irbtools - improvements for Ruby's IRB console (includes methodfinder)

• Other Implementations - a list of related projects in Ruby and other languages

2.2.4

• Michael Kohl

The gem is available as open source under the terms of the MIT License.