title: Function or functor as template parameter? (If it does not need a state)
body: <p>The advantage of functors with respect to functions is said to be that they <a href="https://stackoverflow.com/q/356950/2436175">keep a state</a>.
  Let's say in my problem this is not a relevant feature.</p>
  
  <p>When I am defining a templated function/class, is there any rule for choosing if it would be better to have a function or a functor as template parameter? Or can I basically do the same thing, so does it depend on my taste?</p>
  
  <p>(Related question: <a href="https://stackoverflow.com/questions/4393843/functor-vs-template-parameters">Functor vs template parameters</a>)</p>
  
  <p><strong>Edit:</strong><br/>
  My question is partially answered (for the user side) here: <a href="https://stackoverflow.com/questions/9288694/reason-to-use-this-stateless-class-with-a-function-call-operator-vs-a-c-style-fu">Reason to use this stateless class with a function call operator vs a c style function?</a></p>