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#Bug Off!

Remember way back when we were showing off new gems we discovered from a very !? Well you've been using them ALL, right? At least Pry?

There are two main uses for PRY, to use in place of IRB and to step through our code while running a program in terminal.

Pry is another Ruby REPL, much like IRB, with some added functionality.

When Instead of using a bunch of 'puts' commands in a program, we can use PRY to pause our code and

1. Install by running gem install pry in terminal.
2. At the top of a file you want to debug, require 'pry'.
3. In your code, write binding.pry anywhere in your code where you want to pause the code that's being run. Doing so will allow you to evaluate what code is doing up to that point, like checking what what a variable equals while being changed in a loop.

Because programs get read from top to bottom, any code that comes after a binding.pry command will not be read. Run the code in the exercise below, as you would normally (ruby exercise.rb). To exit, type 'exit' and push enter.

require 'pry'
def useful_method
    first_variable = "Something useful"
    puts first_variable
    binding.pry
    another_variable = "Where am I!?"
    puts another_variable
    first_variable = "Time for change"
end

The following code is not coming out as expected. Oh bugger. Let's use pry to dig into what is causing the problem!

def add_5_years(age)
  5.times do
    age + 1
  end
end

puts add_5_years(50)

I'm so glad you asked!

Pry also have the following handy commands that let you see what objects are currently available in your program to focus on and interact directly with.

• ls, shows you the local variables defined in the current context, and any public methods or instance variables defined on the current object.
• cd, command is used to move into a new object (or scope) inside a Pry session. When inside the new scope it becomes the self for the session and all commands and methods will operate on this new self.

Open your scrabble or Bank Account project and inspect functionality of your code using PRY! Practice using the ls and cd commands.

Dig into Pry's documentation (with screencasts) to learn even more!

Here's a handy list with more Pry commands!