Module: Kernel

### Home Classes Methods

### In Files

- lib/active_support/core_ext/kernel/debugger.rb
- lib/active_support/core_ext/kernel/reporting.rb
- lib/active_support/core_ext/kernel/requires.rb
- lib/active_support/core_ext/kernel/singleton_class.rb

### Methods

- #breakpoint
- #class_eval
- #debugger
- #enable_warnings
- #require_library_or_gem
- #silence_stream
- #silence_warnings
- #singleton_class
- #suppress
- #with_warnings

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No matching classes.

# Kernel

### Public Instance Methods

breakpoint() click to toggle source

    # File 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) click to toggle source

class_eval on an object acts like singleton_class.class_eval.

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

debugger() click to toggle source

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

    # File lib/active_support/core_ext/kernel/debugger.rb, line 4
    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

enable_warnings() click to toggle source

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

    # File lib/active_support/core_ext/kernel/reporting.rb, line 15
    def enable_warnings
      with_warnings(true) { yield }
    end

require_library_or_gem(library_name) click to toggle source

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

    # File lib/active_support/core_ext/kernel/requires.rb, line 6
    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) click to toggle source

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 lib/active_support/core_ext/kernel/reporting.rb, line 39
    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

silence_warnings() click to toggle source

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 lib/active_support/core_ext/kernel/reporting.rb, line 10
    def silence_warnings
      with_warnings(nil) { yield }
    end

singleton_class() click to toggle source

Returns the object’s singleton class.

    # File lib/active_support/core_ext/kernel/singleton_class.rb, line 3
    def singleton_class
      class << self
        self
      end
    end

suppress(*exception_classes) click to toggle source

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 lib/active_support/core_ext/kernel/reporting.rb, line 56
    def suppress(*exception_classes)
      begin yield
      rescue Exception => e
        raise unless exception_classes.any? { |cls| e.kind_of?(cls) }
      end
    end

with_warnings(flag) click to toggle source

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

    # File lib/active_support/core_ext/kernel/reporting.rb, line 20
    def with_warnings(flag)
      old_verbose, $VERBOSE = $VERBOSE, flag
      yield
    ensure
      $VERBOSE = old_verbose
    end

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