What is PRY? Why do we need PRY? Why read an article on PRY? Some of these questions might pop up in your mind when you read the title of this blog. Let me explain why you should be knowing about PRY.
PRY is an attempt to remake IRB, the interactive Ruby interpreter, in a way that makes more sense for mordern programmers. Some of the most important features of PRY are syntax highlighting, code indentation and code debugging. In other words, instead of coding inside a REPL session, you can start a REPL session inside your code execution with the help of PRY. Installing PRY Since PRY is a Ruby gem, installing it is straightforward. The following commands will work:
$ gem install pry $ pry
FeaturesPRY colorizes the syntax as it is typed into the console just like most mordern editors. In addition to this, PRY also auto-indents code thus allowing ensuring that the ‘end’ words line up with the lines that open the block.
pry(main) > class User pry(main)* def greet pry(main)* puts "Hello world" pry(main)* end pry(main)* endAnother cool feature of PRY, as per my opinion, is it’s ability to show a method’s documentation and source code inside REPL. Having this feature inside PRY lets us bypass using `ri` to search for method documentations. Since PRY directly extracts it from source code, we don’t require RDoc to be installed. The documentation and/or source code can be viewed inside PRY using `show-doc` and `show-method` commands. PRY as Debugger Coming to one of the most important features of PRY, its role as a debugger during code execution. Generally, `puts` statements are used to output current values for debugging purposes or bona-fide debuggers are required. When using PRY, it automatically opens an IRB session at the current execution point and makes the whole program state, at that specific point, available. If you want to specify exactly when the
binding.prywill crack open a pry-session. I do this with Ruby code conditionals:
To use PRY, the Gemfile of your Rails application should contain `gem pry`. Take care to place PRY under the development group. Once this is done, you can add the line `binding.pry` inside your code. Whenever Ruby interpreter executes that line, it stops further execution and opens up a PRY REPL session at that point. In case you want PRY sessions to open under certain conditions, you could do the following with Ruby code conditionals: Interactive modification of runtime state It might be convenient to open a PRY session in the middle of an executing program to modify the runtime state. Using `cd` and `ls` commands, the navigation feels natural and familiar. You can also pop in and out of objects, nesting sessions as deeply as you like. Customizability PRY can be easily customized using an user’s `.pryrc` file. Starting from the color of the prompt, to enabling/disabling of history or specifying the editor to be used with PRY are some of the configurations that you can set. Advanced users can even set the Input and Output objects from using the default values of `Readline` and `$stdout`. As a conclusion to this article, I would say that these are just some points of PRY that were interesting to me. For a more thorough reading, you could look up the following sites: http://pryrepl.org/ https://github.com/pry/pry/ ]]>
binding.pry if session[:added_to_cart] == false binding.pry if @first_name == "Jeena" binding.pry if iteration > 5