Pry Everywhere

I’m generally sceptical about alternatives of tools that work just fine like IRB. And I really like IRB. So why Pry? And why everywhere? Because Pry features blew my mind. When I wrote about IRB customization, I was doing what I always do when I like a tool: customize it in order to make it more familiar with my way of thinking. So, when I run into Pry, some of its features blew my mind because they were exactly what I really wanted in IRB. For example, sometimes I like to quickly explore a class or an object. The way you can do it with Pry feels natural and intuitive:

1.9.2 (main):0 > cd Array
1.9.2 (Array):1 > ls -m
[:[], :allocate, :new, :superclass, :toy, :try_convert, :yaml_tag]
1.9.2 (Array):1 > show-
show-command show-doc show-input show-method show-source
1.9.2 (Array):1 > show-method toy

From: /home/lucapette/.pryrc @ line 15:
Number of lines: 3

def self.toy(n=10, &block)
  block_given? ? Array.new(n,&block) : Array.new(n) { |i| i+1 }
end

Toy is a little method I have in my .pryrc (and previously in my .irbrc) that I use when I want to play with arrays. Pry comes with wonderful commands like cd that operates both with classes and instance objects or like ls that you can use to list all the class methods (-m option) or instance methods (-M option). And a very long list of other terrific features as editor integration, shell integration or gist integration. But I don’t need to persuade you to use Pry because I’m sure you will use it after taking a look at these wonderful resources.

The title of this article is “Pry everywhere” so let me show you what I’ve done to migrate to Pry. There are existing of solutions but they all involve something I don’t like especially about their rails integration. My requirements were fairly simple:

I don’t want to lose the customizations I’ve done with IRB
The same for rails console
I don’t want to add any gem (although this is very nicely done) to my Gemfile in rails projects.

After some researching, I came up with the following solution:

My current .irbrc:


# https://github.com/carlhuda/bundler/issues/183#issuecomment-1149953

if defined?(::Bundler)
  global*gemset = ENV['GEM_PATH'].split(':').grep(/ruby.*@global/).first
  if global*gemset
    all_global_gem_paths = Dir.glob("#{global_gemset}/gems/*")
      all_global_gem_paths.each do |p|
        gem_path = "#{p}/lib"
        $LOAD_PATH << gem_path
      end
   end
end

# Use Pry everywhere

require "rubygems"
require 'pry'
Pry.start
exit

In short, every time I start IRB I start a Pry session. It feels like a dirty solution and I’m not sure if it has any issues. For now, it’s working just fine with my requirements. The bundler code is necessary to require pry and other gems from rvm global gemset in a rails console without declaring them in the Gemfile. Then, in the .pryrc I have:

# vim FTW

Pry.config.editor = "gvim --nofork"

# My pry is polite

Pry.hooks = { :after_session => proc { puts "bye-bye" } }

# Prompt with ruby version

Pry.prompt = [proc { |obj, nest_level| "#{RUBY_VERSION} (#{obj}):#{nest_level} > " }, proc { |obj, nest_level| "#{RUBY_VERSION} (#{obj}):#{nest_level} * " }]

%w{map_by_method hirb}.each { |gem| require gem }

# Toys methods

# Stole from https://gist.github.com/807492
class Array
  def self.toy(n=10, &block)
    block_given? ? Array.new(n,&block) : Array.new(n) {|i| i+1}
  end
end

class Hash
  def self.toy(n=10)
    Hash[Array.toy(n).zip(Array.toy(n){|c| (96+(c+1)).chr})]
  end
end

# loading rails configuration if it is running as a rails console

load File.dirname(**FILE**) + '/.railsrc' if defined?(Rails) && Rails.env

If you compare this file with my previous .irbrc you’ll notice that this one is shorter. Pry is indeed doing part of what I need by default. Things like colors and history commands.

My .railsrc is very similar to the previous one minus one difference that is relevant to hirb users:

# https://github.com/cldwalker/hirb/issues/46#issuecomment-1870823

Pry.config.print = proc do |output, value|
  Hirb::View.view_or_page_output(value) || Pry::DEFAULT_PRINT.call(output, value)
end

Hirb.enable

This makes Hirb work flawlessly. The combination of Rails and Pry is fantastic. Give it a try!

Pry Everywhere

See also