In Ruby, if I do this:
  x++

then I get a syntax error.  However, if I do this:
  ++x

then I do not get a syntax error.  I'm guessing that Ruby parses this
as:
  +(+(x))

which is fine, except that a seasoned C++ programmer is trained to use
the preincrement operator, and may type this by mistake.  Would it be
wise to have the interpreter emit a warning for this case?  I cannot
think of any good reason to ever use ++x in an expression in Ruby.

Paul