anchor.diff:  --------------------------------------------------
   *Input*:
   
  -<1> string expression
  -<2> string expression
  -
  -*Output*: string
  -
  -*Description*: Returns a character string that is the result of concatenating `string_exp1` to `string_exp2`. `null` input strings are treated as empty strings.
  +<1> string expression. Treats `null` as an empty string.
  +<2> string expression. Treats `null` as an empty string.
  +
  +*Output*: string
  +
  +*Description*: Returns a character string that is the result of concatenating `string_exp1` to `string_exp2`.
   
   [source, sql]
   --------------------------------------------------
  
positive.code: --------------------------------------------------
  *Input*:
  
  <1> integer expression. If `null` or negative, the function returns `null`.
  
  *Output*: string
  
  *Description*: Returns the character that has the ASCII code value specified by the numeric input. The value should be between 0 and 255; otherwise, the return value is data source–dependent.
  
  [source, sql]
  --------------------------------------------------
  
negative.code: 
  *Output*: boolean value
  
  *Description*: Returns `true` if the source expression starts with the specified
  pattern, `false` otherwise. The matching is case sensitive.
  
  [source, sql]
  --------------------------------------------------
  