I wrote the function that validates tagnames last night. Here is the skinny on what is allowed.
- Tagnames can be no longer than DAX_TAGNAME_SIZE which is #define'd as 32 right now but could be changed easy enough. The tagname is stored as a fixed size char array in the taglist.
- Tagnames are case sensitive. TagName and tagName are different tags.
- Characters are limited to alpha numeric characters and the underscore '_'.
- The first character must be a letter or an underscore. Numbers are allowed in tagnames but can't be the first character.