anchor.diff:  	  (decimal_constraint {$len1 = $decimal_constraint.len1; $len2 = $decimal_constraint.len2;})? 
   	  (SIGNED | UNSIGNED {$type=$type + " UNSIGNED";})?
   	| enum_or_set_data_type {$type = $enum_or_set_data_type.type; $len1 = $enum_or_set_data_type.len1;}
  -	| SERIAL {$type = "SERIAL";}
  +	| spatial_data_type {$type = $spatial_data_type.type;}
   	;
   
   data_type returns [String type]
  
positive.code: 	| BIT {$type = "BIT";}
  	| BINARY {$type = "BINARY";}
  	| VARBINARY {$type = "VARBINARY";}
  	;
  	
  numeric_data_type returns [String type]
  
negative.code: NATIONAL = 'national';
  NCHAR = 'nchar';
  NVARCHAR = 'nvarchar';
  GEOMETRY = 'geometry';
  GEOMETRYCOLLECTION = 'geometrycollection';
  POINT = 'point';
  MULTIPOINT  = 'multipoint';
  LINESTRING = 'linestring';
  MULTILINESTRING = 'multilinestring';
  POLYGON = 'polygon';
  MULTIPOLYGON = 'multipolygon';
  }
  
  @header {
  