title: What is ++ operator doing in Python?
body: <p>Python doesn't support C-style <code>++a</code> increment but, to my surprise, it doesn't complain either leading to me being temporarily baffled as to why my loop wasn't working.</p>
  
  <p>Trying a few things (having first initialised with <code>a=0</code>) I find that <code>a++</code> and <code>a--</code> produce a syntax error, but <code>++a</code> doesn't. While <code>--a</code> produces a syntax error in Python 3.3 but not in Python 2.7.</p>
  
  <p>What's going on? Why doesn't <code>++a</code> give an error? Why does <code>--a</code> not give an error in 2.7 but does give an error in 3.3?</p>