title: Drupal Views api, add simple argument handler
body: <p>Background: I have a complex search form that stores the query and it's hash in a cache. Once the cache is set, I redirect to something like <code>/searchresults/e6c86fadc7e4b7a2d068932efc9cc358</code> where that big long string on the end is the md5 hash of my query. I need to make a new argument for views to know what the hash is good for.</p>
  
  <p>The reason for all this hastle is because my original search form is way to complex and has way to many arguments to consider putting them all into the path and expecting to do the filtering with the normal views arguments.</p>
  
  <p>Now for my question. I have been reading views 2 documentation but not figuring out how to accomplish this custom argument. It doesn't seem to me like this should be as hard as it seems to me like it must be. Leaving aside any knowledge of the veiws api, it would seem that all I need is a callback function that will take the argument from the path as it's only argument and return a list of node id's to filter to.</p>
  
  <p>Can anyone point me to a solution or give me some example code?</p>
  
  <p>Thanks for your help! You guys are great.</p>
  
  <p>PS. I am pretty sure that my design is the best I can come up with, lets don't get off my question and into cross checking my design logic if we can help it.</p>