anchor.diff:  a|
   The Property value is equal to any one of several values, which are separated by a
   
  -|
  -| | a|
  -pipe (|) character. See _Regular Expressions_, below, for more information.
  -
  -|
  -| | | |
  -| | | |
  +a|\|
  +a|
  +pipe (\|) character.
  +a|See _Regular Expressions_, below, for more information.
  +
   a|
   !~
   
  
positive.code: a|
  The two values are not the same. (The exclamation point (!) is known as a ʻbangʼ.)
  
  |
  | | | |
  a|
  =~
  
  
negative.code: 
  The following table shows each valid operator, the meaning, and under what conditions a comparison using the operator will be true.
  
  [cols=",,",]
  |=======================================================================================
  a|
  *Operator*
  