The Ruby Way: Solutions and Techniques in Ruby Programming, Second Edition

16.4. Using irb As a Debugger

The ruby-breakpoint library is the creation of Florian Gross. This wonderful little tool enables you to set breakpoints in your code with the breakpoint method. When a breakpoint is encountered, you are thrown into an irb session. (The irb tool, interactive Ruby, is covered in more detail in Chapter 21.)

This is not part of the standard library. Install it by doing a gem install ruby-breakpoint or by any other method.

Let’s take Listing 16.4 and make a couple of changes. We’ll add require 'breakpoint' at the beginning and then add a call to the breakpoint method sometime after both the gets calls:

require 'breakpoint'

# ...
w2 = gets.chomp

breakpoint

# ...

Now let’s run this. The following session shows how we enter ...