Sequel::MigrationReverser

Handles the reversing of reversible migrations. Basically records supported methods calls, translates them to reversed calls, and returns them in reverse order.

Methods

Public Class

new

Public Instance

reverse

Public Class methods

new()

    # File lib/sequel/extensions/migration.rb
181 def initialize
182   @actions = []
183 end

Public Instance methods

reverse(&block)

Reverse the actions for the given block. Takes the block given and returns a new block that reverses the actions taken by the given block.

    # File lib/sequel/extensions/migration.rb
188 def reverse(&block)
189   instance_exec(&block)
190 rescue NoMethodError => e
191   Proc.new{raise Sequel::Error, "irreversible migration method \"#{e.name}\" used in #{block.source_location.first}, you may need to write your own down method"}
192 rescue => e
193   Proc.new{raise Sequel::Error, "unable to reverse migration due to #{e.class} in #{block.source_location.first}, you may need to write your own down method"}
194 else
195   actions = @actions.reverse
196   Proc.new do
197    actions.each do |a|
198     pr = a.last.is_a?(Proc) ? a.pop : nil
199     # Allow calling private methods as the reversing methods are private
200     send(*a, &pr)
201    end
202   end
203 end