module Kernel

def capture(stream)


stream # => "Cool\n"
stream = capture(:stdout) { puts "Cool" }

Captures the given stream and returns it: 
def capture(stream)
  begin
    stream = stream.to_s
    eval "$#{stream} = StringIO.new"
    yield
    result = eval("$#{stream}").string
  ensure
    eval("$#{stream} = #{stream.upcase}")
  end
  result
end

def class_eval(*args, &block)

class_eval on an object acts like singleton_class.class_eval. 
def class_eval(*args, &block)
  singleton_class.class_eval(*args, &block)
end

def debugger

Starts a debugging session if ruby-debug has been loaded (call rails server --debugger to do load it). 
def debugger
  message = "\n***** Debugger requested, but was not available (ensure ruby-debug is listed in Gemfile/installed as gem): Start server with --debugger to enable *****\n"
  defined?(Rails) ? Rails.logger.info(message) : $stderr.puts(message)
end

def enable_warnings

Sets $VERBOSE to true for the duration of the block and back to its original value afterwards. 
def enable_warnings
  with_warnings(true) { yield }
end

def quietly


quietly { system 'bundle install' }

Silences both STDOUT and STDERR, even for subprocesses. 
def quietly
  silence_stream(STDOUT) do
    silence_stream(STDERR) do
      yield
    end
  end
end

def silence_stderr #:nodoc:

:nodoc:
For compatibility 
def silence_stderr #:nodoc:
  silence_stream(STDERR) { yield }
end

def silence_stream(stream)

puts 'But this will'

end
puts 'This will never be seen'
silence_stream(STDOUT) do

Silences any stream for the duration of the block. 
def silence_stream(stream)
  old_stream = stream.dup
  stream.reopen(RbConfig::CONFIG['host_os'] =~ /mswin|mingw/ ? 'NUL:' : '/dev/null')
  stream.sync = true
  yield
ensure
  stream.reopen(old_stream)
end

def silence_warnings

noisy_call # warning voiced

end
value = noisy_call # no warning voiced
silence_warnings do

Sets $VERBOSE to nil for the duration of the block and back to its original value afterwards. 
def silence_warnings
  with_warnings(nil) { yield }
end

def singleton_class

Returns the object's singleton class. 
def singleton_class
  class << self
    self
  end
end unless respond_to?(:singleton_class) # exists in 1.9.2

def suppress(*exception_classes)

puts "This code gets executed and nothing related to ZeroDivisionError was seen"

end
puts "This code is NOT reached"
1/0
suppress(ZeroDivisionError) do

Blocks and ignores any exception passed as argument if raised within the block. 
def suppress(*exception_classes)
  begin yield
  rescue Exception => e
    raise unless exception_classes.any? { |cls| e.kind_of?(cls) }
  end
end

def with_warnings(flag)

Sets $VERBOSE for the duration of the block and back to its original value afterwards. 
def with_warnings(flag)
  old_verbose, $VERBOSE = $VERBOSE, flag
  yield
ensure
  $VERBOSE = old_verbose
end