Format 1 - Identifier

1 data-name-1
2+ 
2.0? 
2.0.0 IN
2.0.0 OF
2.0.1 data-name-2
3? 
3.0 IN
3.0 OF
3.1 file-name-1
4? (
4.1+ 
4.1 subscript
4.2 )
5? ( leftmost-character-position :
5.1? length
5.2 )