Class Sequel::MigrationReverser
In: lib/sequel/extensions/migration.rb
Parent: Sequel::BasicObject

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

Methods

new   reverse  

Public Class methods

new()

[Source]

     # File lib/sequel/extensions/migration.rb, line 125
125:     def initialize
126:       @actions = []
127:     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.

[Source]

     # File lib/sequel/extensions/migration.rb, line 132
132:     def reverse(&block)
133:       begin
134:         instance_eval(&block)
135:       rescue
136:         just_raise = true
137:       end
138:       if just_raise
139:         Proc.new{raise Sequel::Error, 'irreversible migration method used, you may need to write your own down method'}
140:       else
141:         actions = @actions.reverse
142:         Proc.new do
143:           actions.each do |a|
144:             if a.last.is_a?(Proc)
145:               pr = a.pop
146:               send(*a, &pr)
147:             else
148:               send(*a)
149:             end
150:           end
151:         end
152:       end
153:     end

[Validate]