anchor.diff:  %import common.FLOAT
   %import common.INT
   
  -STRING1: /".*?(?<!\\\\)(\\\\\\\\)*?"i?/
  -STRING2: /'.*?(?<!\\\\)(\\\\\\\\)*?'i?/
  -STRING3: /`.*?`i?/   // XXX TODO
  +// UNQUOTED_STRING: /[a-z_][a-z0-9_\-]*/i
  +UNQUOTED_STRING: /[a-z0-9_\-]+/i
  +DOUBLE_QUOTED_STRING: /".*?(?<!\\\\)(\\\\\\\\)*?"i?/
  +SINGLE_QUOTED_STRING: /'.*?(?<!\\\\)(\\\\\\\\)*?'i?/
  +ESCAPED_STRING: /`.*?`i?/
  +//KEYWORD: /[a-z]+/i
  +
  +//UNQUOTED_NUMERIC_STRING: /[a-z_][a-z0-9_\-]*/i
  +
   REGEXP1.2: /\/.*?\/i?/
   REGEXP2: /\\\\.*?\\\\i?/
  +
   RUNTIME_VAR: /%.*?%/
   
   COMMENT: /\#[^\n]*/
  
positive.code: %ignore COMMENT
  %ignore CCOMMENT
  %ignore WS
  
negative.code:             | "REFERENCE"i
              | "SCALEBAR"i
              | "SCALETOKEN"i
              | "WEB"i
              | STYLE
  			| SYMBOL
  
  SYMBOL: "SYMBOL"i
  STYLE: "STYLE"i
  
  AUTO: "AUTO"i
  PATH: /([a-z0-9_]*\.*\/|[a-z_]+[.\/])[a-z0-9_\/\.-]+/i
  
  // rules allow optional alphachannel
  DOUBLE_QUOTED_HEXCOLOR.2: /\"#(?:[0-9a-fA-F]{3}){1,2}([0-9a-fA-F]{2})?\"/ 
  SINGLE_QUOTED_HEXCOLOR.2: /'#(?:[0-9a-fA-F]{3}){1,2}([0-9a-fA-F]{2})?'/ 
  
  NULL: "NULL"i
  
  SIGNED_FLOAT: ["-"|"+"] FLOAT
  