anchor.diff:      ;
   
   interpolation
  -    : namespace_? Hash BlockStart namespace_? ( value | parent ) BlockEnd
  +    : namespace_? Hash BlockStart namespace_? ( ifExpression | value | parent ) BlockEnd
       ;
   
   parent
  
positive.code:     ;
  
  ifExpression
      : If Lparen expression Comma value Comma value Rparen prio?
      ;
  
  
  
negative.code: through
      : Number ws
      | functionCall
      | expression
      ;
  
  whileDeclaration
  