Since Ruby is very dynamic, methods added to the ancestors of BlankSlate after BlankSlate is definedwill show up in the list of available BlankSlate methods. We handle this by defining a hook in the Object and Kernel classes that will hide any method defined after BlankSlate has been loaded.

Methods
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Class Public methods
blank_slate_method_added(name)
method_added(name)

Detect method additions to Kernel and remove them in the BlankSlate class.

Also aliased as: blank_slate_method_added
# File activesupport/lib/active_support/vendor/builder-2.1.2/blankslate.rb, line 65
def method_added(name)
  result = blank_slate_method_added(name)
  return result if self != Kernel
  BlankSlate.hide(name)
  result
end
Instance Public methods
breakpoint()
# File activesupport/lib/active_support/core_ext/kernel/debugger.rb, line 11
def breakpoint
  message = "\n***** The 'breakpoint' command has been renamed 'debugger' -- please change *****\n"
  defined?(Rails) ? Rails.logger.info(message) : $stderr.puts(message)
  debugger
end
class_eval(*args, &block)

#class_eval on an object acts like singleton_class.class_eval.

# File activesupport/lib/active_support/core_ext/kernel/singleton_class.rb, line 10
def class_eval(*args, &block)
  singleton_class.class_eval(*args, &block)
end
daemonize()

Turns the current script into a daemon process that detaches from the console. It can be shut down with a TERM signal.

# File activesupport/lib/active_support/core_ext/kernel/daemonizing.rb, line 4
def daemonize
  Process.daemon
end
debugger()

Starts a debugging session if ruby-debug has been loaded (call script/server –debugger to do load it).

# File activesupport/lib/active_support/core_ext/kernel/debugger.rb, line 4
def debugger
  message = "\n***** Debugger requested, but was not available: Start server with --debugger to enable *****\n"
  defined?(Rails) ? Rails.logger.info(message) : $stderr.puts(message)
end
enable_warnings()

Sets $VERBOSE to true for the duration of the block and back to its original value afterwards.

# File activesupport/lib/active_support/core_ext/kernel/reporting.rb, line 17
def enable_warnings
  old_verbose, $VERBOSE = $VERBOSE, true
  yield
ensure
  $VERBOSE = old_verbose
end
require_library_or_gem(library_name)

Require a library with fallback to RubyGems. Warnings during library loading are silenced to increase signal/noise for application warnings.

# File activesupport/lib/active_support/core_ext/kernel/requires.rb, line 4
def require_library_or_gem(library_name)
  silence_warnings do
    begin
      require library_name
    rescue LoadError => cannot_require
      # 1. Requiring the module is unsuccessful, maybe it's a gem and nobody required rubygems yet. Try.
      begin
        require 'rubygems'
      rescue LoadError => rubygems_not_installed
        raise cannot_require
      end
      # 2. Rubygems is installed and loaded. Try to load the library again
      begin
        require library_name
      rescue LoadError => gem_not_installed
        raise cannot_require
      end
    end
  end
end
silence_stream(stream)

Silences any stream for the duration of the block.

silence_stream(STDOUT) do
  puts 'This will never be seen'
end
puts 'But this will'
# File activesupport/lib/active_support/core_ext/kernel/reporting.rb, line 36
def silence_stream(stream)
  old_stream = stream.dup
  stream.reopen(RUBY_PLATFORM =~ /(:?mswin|mingw)/ ? 'NUL:' : '/dev/null')
  stream.sync = true
  yield
ensure
  stream.reopen(old_stream)
end
silence_warnings()

Sets $VERBOSE to nil for the duration of the block and back to its original value afterwards.

silence_warnings do
  value = noisy_call # no warning voiced
end
noisy_call # warning voiced
# File activesupport/lib/active_support/core_ext/kernel/reporting.rb, line 9
def silence_warnings
  old_verbose, $VERBOSE = $VERBOSE, nil
  yield
ensure
  $VERBOSE = old_verbose
end
singleton_class()

Returns the object's singleton class.

# File activesupport/lib/active_support/core_ext/kernel/singleton_class.rb, line 3
def singleton_class
  class << self
    self
  end
end
suppress(*exception_classes)

Blocks and ignores any exception passed as argument if raised within the block.

suppress(ZeroDivisionError) do
  1/0
  puts "This code is NOT reached"
end
puts "This code gets executed and nothing related to ZeroDivisionError was seen"
# File activesupport/lib/active_support/core_ext/kernel/reporting.rb, line 53
def suppress(*exception_classes)
  begin yield
  rescue Exception => e
    raise unless exception_classes.any? { |cls| e.kind_of?(cls) }
  end
end