Kernel
Methods
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Instance Public methods
class_eval(*args, &block)

#class_eval on an object acts like singleton_class.class_eval.

Source: show | on GitHub 

# File activesupport/lib/active_support/core_ext/kernel/singleton_class.rb, line 3
def class_eval(*args, &block)
  singleton_class.class_eval(*args, &block)
end
concern(topic, &module_definition)

A shortcut to define a toplevel concern, not within a module.

See Module::Concerning for more.

Source: show | on GitHub 

# File activesupport/lib/active_support/core_ext/kernel/concern.rb, line 9
def concern(topic, &module_definition)
  Object.concern topic, &module_definition
end
enable_warnings()

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

Source: show | on GitHub 

# File activesupport/lib/active_support/core_ext/kernel/reporting.rb, line 18
def enable_warnings
  with_warnings(true) { yield }
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

Source: show | on GitHub 

# File activesupport/lib/active_support/core_ext/kernel/reporting.rb, line 12
def silence_warnings
  with_warnings(nil) { yield }
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'

Source: show | on GitHub 

# File activesupport/lib/active_support/core_ext/kernel/reporting.rb, line 39
def suppress(*exception_classes)
  yield
rescue *exception_classes
end
with_warnings(flag)

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

Source: show | on GitHub 

# File activesupport/lib/active_support/core_ext/kernel/reporting.rb, line 24
def with_warnings(flag)
  old_verbose, $VERBOSE = $VERBOSE, flag
  yield
ensure
  $VERBOSE = old_verbose
end