lib/sup/undo.rb

lib/sup/undo.rb (901B) - raw
      1 module Redwood
      2 
      3 ## Implements a single undo list for the Sup instance
      4 ##
      5 ## The basic idea is to keep a list of lambdas to undo
      6 ## things. When an action is called (such as 'archive'),
      7 ## a lambda is registered with UndoManager that will
      8 ## undo the archival action
      9 
     10 class UndoManager
     11   include Redwood::Singleton
     12 
     13   def initialize
     14     @@actionlist = []
     15   end
     16 
     17   def register desc, *actions, &b
     18     actions = [*actions.flatten]
     19     actions << b if b
     20     raise ArgumentError, "need at least one action" unless actions.length > 0
     21     @@actionlist.push :desc => desc, :actions => actions
     22   end
     23 
     24   def undo
     25     unless @@actionlist.empty?
     26       actionset = @@actionlist.pop
     27       actionset[:actions].each { |action| action.call }
     28       BufferManager.flash "undid #{actionset[:desc]}"
     29     else
     30       BufferManager.flash "nothing more to undo!"
     31     end
     32   end
     33 
     34   def clear
     35     @@actionlist = []
     36   end
     37 end
     38 end
sup.git
