activerecord/lib/active_record/migration/command_recorder.rb
# Returns the inverse of the given command. For example:
#
#   recorder.inverse_of(:rename_table, [:old, :new])
#   # => [:rename_table, [:new, :old]]
#
# This method will raise an +IrreversibleMigration+ exception if it cannot
# invert the +command+.
Returns the inverse of the given command.

This method will raise an +IrreversibleMigration+ exception if it cannot
invert the +command+.
Returns the inverse of the given command . This method will raise an + IrreversibleMigration + exception if it cannot invert the + command + .
def inverse_of(command, args, &block)
        method = :"invert_#{command}"
        raise IrreversibleMigration unless respond_to?(method, true)
        send(method, args, &block)
      end
def inverse_of ( command , args , & block ) method = :" invert_ #{ command } " raise IrreversibleMigration unless respond_to? ( method , true ) send ( method , args , & block ) end
Returns the inverse of the given command.
Returns the inverse of the given command .
command
args
block