title: Conditional module aliasing
body: <p>For a class project I am writing a program that evaluates the performance of different implementations of the same abstract data structure.  Since I am using identical code to test each of them, I would like to be able to set a module alias depending on user input and just run that module through the testing code.</p>
  
  <p>In other words, I want something like:</p>
  
  <pre><code>let module M = 
    if model = "tree" then TreeModel else
    if model = "hash" then HashModel else
    ListModel
  in ...
  </code></pre>
  
  <p>Is there a way I can make this work, or am I going about this all wrong?</p>