Hacking IRB WorkSpace

hacked_workspace.rb

require 'irb/workspace'

module IRB
  class WorkSpace

    alias evaluate__orig evaluate

    def evaluate(ctx, stmts, file=__FILE__, line=__LINE__)

      result = evaluate__orig(ctx,stmts,file,line)

      if result.is_a?(Numeric)
        result + 1
      elsif result.is_a?(String)
        result.reverse
      else
        !result
      end

    end
  end
end