anchor.diff:   * https://github.com/cplusplus/draft/blob/master/papers/n4140.pdf
    * and
    * http://www.nongnu.org/hcb/
  - * 
  + *
    * Possible Issues:
  - * 
  + *
    * Input must avoid conditional compilation blocks (this grammar ignores any preprocessor directive)
    * GCC extensions not yet supported (do not try to parse the preprocessor output)
    * Right angle bracket (C++11) - Solution '>>' and '>>=' are not tokens, only '>'
  
positive.code: 
  alignmentspecifier
  :
  	Alignas '(' typeid '...'? ')'
  	| Alignas '(' constantexpression '...'? ')'
  ;
  
  
negative.code: typeparameter
  :
  	Class '...'? Identifier?
  	| Class Identifier? '=' thetypeid
  	| Typename '...'? Identifier?
  	| Typename Identifier? '=' thetypeid
  	| Template '<' templateparameterlist '>' Class '...'? Identifier?
  	| Template '<' templateparameterlist '>' Class Identifier? '=' idexpression
  ;
  