pry-demo.rb

require 'pry'

class Thing
  def initialize
    @m = {jonathan: 5, richard: 3, anna: 7}
    @ks = [:jonathan, :anna, :rikard]
  end

  def get_count(name)
    if @m.include?(name)
      @m[name]
    else
      binding.pry
      raise RuntimeError.new("no entry by that key: #{name}")
    end
  end

  def get_counts
    @ks.map do |k|
      get_count(k)
    end
  end
end

def main
  t = Thing.new
  puts t.get_counts
end

main

pry-session.rb

0 ruby ruby ./20160527-scratch.rb

Frame number: 0/4

From: /Users/joni/Scratch/LighthouseLabs/ruby/20160527-scratch.rb @ line 13 Thing#get_count:

     9: def get_count(name)
    10:   if @m.include?(name)
    11:     @m[name]
    12:   else
 => 13:     binding.pry
    14:     raise RuntimeError.new("no entry by that key: #{name}")
    15:   end
    16: end

pry> name
=> :rikard
pry> show-stack -v

Showing all accessible frames in stack (5 in total):
--
=> #0  get_count <Thing#get_count(name)>
      in #<Thing> @ ./20160527-scratch.rb:13
   #1 [block]   block in get_counts <Thing#get_counts()>
      in #<Thing> @ ./20160527-scratch.rb:20
   #2 [method]  get_counts <Thing#get_counts()>
      in #<Thing> @ ./20160527-scratch.rb:19
   #3 [method]  main <Object#main()>
      in main @ ./20160527-scratch.rb:27
   #4 [main]    <main>
      in main @ ./20160527-scratch.rb:30
pry> up 1

Frame number: 1/4
Frame type: block

From: /Users/joni/Scratch/LighthouseLabs/ruby/20160527-scratch.rb @ line 20 Thing#get_counts:

    18: def get_counts
    19:   @ks.map do |k|
 => 20:     get_count(k)
    21:   end
    22: end

pry> k
=> :rikard
pry> @ks
=> [:jonathan, :anna, :rikard]
pry> continue
NameError: undefined local variable or method `continue' for #<Thing:0x007feb6b010e60>
from (pry):4:in `block in get_counts'
pry> exit
./20160527-scratch.rb:14:in `get_count': no entry by that key: rikard (RuntimeError)
	from ./20160527-scratch.rb:20:in `block in get_counts'
	from ./20160527-scratch.rb:19:in `map'
	from ./20160527-scratch.rb:19:in `get_counts'
	from ./20160527-scratch.rb:27:in `main'
	from ./20160527-scratch.rb:30:in `<main>'
1 ruby