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 124
124:     def initialize
125:       @actions = []
126:     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 131
131:     def reverse(&block)
132:       begin
133:         instance_eval(&block)
134:       rescue
135:         just_raise = true
136:       end
137:       if just_raise
138:         Proc.new{raise Sequel::Error, 'irreversible migration method used, you may need to write your own down method'}
139:       else
140:         actions = @actions.reverse
141:         Proc.new do
142:           actions.each do |a|
143:             if a.last.is_a?(Proc)
144:               pr = a.pop
145:               send(*a, &pr)
146:             else
147:               send(*a)
148:             end
149:           end
150:         end
151:       end
152:     end

[Validate]