methods for extracting @ list

models/content.rb

 class Content
   include Mongoid::Document
   
+  AT_NOTIFICATION_REGEX = /(?<=^|\s)(@[A-Za-z0-9_]+)(?!\w)/
+  
+  def self.get_marked_text(text)
+    counter = -1
+    text.gsub AT_NOTIFICATION_REGEX do
+      counter += 1
+      "#{$1}_#{counter}"
+    end
+  end
+
+  def self.get_at_position_list(text)
+    list = []
+    text.gsub AT_NOTIFICATION_REGEX do
+      parts = $1.rpartition('_')
+      list << [parts.last.to_i, parts.first[1..-1]]
+    end
+    list
+  end
+
+  def self.get_valid_at_position_list(text)
+    html = Nokogiri::HTML(RDiscount.new(self.get_marked_text(text)).to_html)
+    html.xpath('//code').each do |c|
+      c.children = ''
+    end
+    self.get_at_position_list html.to_s
+  end
+
 end

spec/models/content_spec.rb

+require 'spec_helper'
+
+describe Content do
+  before :each do
+    @text =
+"""
+hi @tom, I have a question from @pi314 about the following code:
+```
+class A
+  def set_some_variable
+    @some_variable = 1
+  end
+end
+```
+and also the following code
+    class A
+      def get_some_variable
+        @some_variable
+      end
+    end
+what is the 'at' symbol doing there? @dementrock
+"""
+  end
+
+  describe "#get_marked_text(text)" do
+    it "returns marked at text" do
+      converted = Content.get_marked_text(@text)
+      converted.should include "@tom_0"
+      converted.should include "@pi314_1"
+      converted.should include "@some_variable_2"
+      converted.should include "@some_variable_3"
+      converted.should include "@dementrock_4"
+    end
+  end
+
+  describe "#get_valid_at_position_list(text)" do
+    it "returns the list of positions for the valid @ notifications, filtering out the ones in code blocks" do
+      list = Content.get_valid_at_position_list(@text)
+      list.should include [0, "tom"]
+      list.should include [1, "pi314"]
+      list.should include [4, "dementrock"]
+      list.length.should == 3
+    end
+  end
+end