title: Elixir - Looping through and adding to map
body: <p>I'm rebuilding something in Elixir from some code I built in C#.</p>
  
  <p>It was pretty hacked together, but works perfectly (although not on Linux, hence rebuild).</p>
  
  <p>Essentially what it did was check some RSS feeds and see if there was any new content. This is the code:</p>
  
  <pre><code>Map historic (URL as key, post title as value).
  List&lt;string&gt; blogfeeds
  while true
  for each blog in blogfeeds
     List&lt;RssPost&gt; posts = getposts(blog)
     for each post in posts
          if post.url is not in historic
             dothing(post)
             historic.add(post)
  </code></pre>
  
  <p>I am wondering how I can do Enumeration effectively in Elixir. Also, it seems that my very process of adding things to "historic" is anti-functional programming.</p>
  
  <p>Obviously the first step was declaring my list of URLs, but beyond that the enumeration idea is messing with my head. Could someone help me out? Thanks.</p>