Added caller context padding example

examples/caller_context_padding.rb

@@ -0,0 +1,80 @@
+#!/usr/bin/env ruby
+#
+# An example showing how the caller_context_padding option works
+#
+# You probably need to run from the parent directory as:
+#
+#   ruby -Ilib examples/caller_context_padding.rb
+#
+require 'deprecatable'
+module A
+  class B
+    extend Deprecatable
+    def initialize
+      @call_count = 0
+    end
+    def deprecate_me
+      @call_count += 1
+      puts "deprecate_me call #{@call_count}"
+    end
+    deprecate :deprecate_me, :message => "This method is to be completely removed", :removal_version => "4.2"
+  end
+end
+
+if $0 == __FILE__
+
+  puts "This is an example of showing how to affect the caller context padding"
+  puts "You can change the caller_context_padding by"
+  puts
+  puts "  1) Setting `Deprecatable.options.caller_context_padding` in ruby code."
+  puts "  2) Setting the DEPRECATABLE_CALLER_CONTEXT_PADDING envionment variable."
+  puts
+  puts "They may be set to an integer value that is >= 1"
+  puts "When you use both (1) and (2) simultaneously, you will see that"
+  puts "setting the environment variable always overrides the code."
+
+  puts
+  puts "Here are some example ways to run this program"
+  puts
+
+  [ nil, "DEPRECATABLE_CALLER_CONTEXT_PADDING=" ].each do |env|
+    (1..3).each do |env_setting|
+      next if env.nil? and env_setting > 1
+      (1..3).each do |cmd_line|
+        next if env and (env_setting == cmd_line)
+        parts = [ "    " ]
+        parts << "#{env}#{env_setting}" if env
+        parts << "ruby -Ilib #{__FILE__} #{cmd_line}"
+        puts parts.join(' ')
+      end
+    end
+  end
+  puts
+  puts "-" * 72
+
+  Deprecatable.options.has_at_exit_report = false
+  Deprecatable.options.caller_context_padding = Float(ARGV.shift || 2 ).to_i
+
+  puts
+  puts "Running with ENV['DEPRECATABLE_CALLER_CONTEXT_PADDING'] => #{ENV['DEPRECATABLE_CALLER_CONTEXT_PADDING']}"
+  puts "Running with Deprecatable.options.caller_context_padding => #{Deprecatable.options.caller_context_padding}"
+  puts "-" * 72
+  puts
+
+  b = A::B.new
+  4.times do
+    # Context before 1.1
+    # Context before 1.2
+    b.deprecate_me
+    # Context after 1.1
+    # Context after 1.2
+  end
+
+  2.times do
+    # Context before 2.1
+    # Context before 2.2
+    b.deprecate_me
+    # Context after 2.1
+    # Context after 2.2
+  end
+end