After every attribute name or attribute value there must be a comma. At the end of lines commas are not necessary but they can be there.
It is a good practice to begin new attribute name or value immediately after the comma although spaces before and after the comma are ignored. Spaces which occur as part of attribute names and values are not ignored and they are accepted as regular printable characters. A good practice is to replace such spaces with underscore characters '_' when possible.
Exceptionally, there can be two or more commas one after other. The meaning is that the attribute name or value which should be between them is actually unknown. The same case is when there are only spaces between commas, because such spaces are ignored. A good practice is to mark unknown values by a '?'.
© 2001 LIS - Rudjer Boskovic Institute
Last modified: March 17 2019 06:59:33.