Re: [netmod] regarding draft-bierman-netmod-yang-data-ext-00

[Kent Watsen <[e-mail]>]

>> Gotcha.  What do other people think, would a "uses-yang-data"
>> statement be generally more useful?
>
> But does this mean we also do uses-yang-container, uses-yang-list,
> uses-yang-xyz to other definitions as well? I do not think this is
> desirable and why would yang-data be any different?


Oh, no.  I view yang-data as a body-stmt, not a data-def-stmt,
akin to 'rpc' and 'notification'.  But back to the draft's 
proposed solution, I understand that augment-stmt is a top-level 
body-stmt, but it's also a uses-stmt, and in that context, it is
a sibling to the refine-stmt.  Already ANIMA has a need to both
augment and refine a yang-data defined structure.  To me, a
'uses-yang-data' statement seems just one step more general than
a 'augment-yang-data' statement.

Specially, if we were updating YANG:

   // just added last entry
   body-stmts          = *(extension-stmt /
                           feature-stmt /
                           identity-stmt /
                           typedef-stmt /
                           grouping-stmt /
                           data-def-stmt /
                           augment-stmt /
                           rpc-stmt /
                           notification-stmt /
                           deviation-stmt /
                           yang-data-stmt)

   // something like this?
   yang-data-stmt            = yang-data-keyword sep identifier-arg-str optsep
                         (";" /
                          "{" stmtsep
                              ;; these stmts can appear in any order
                              [status-stmt]
                              [description-stmt]
                              [reference-stmt]
                              *(typedef-stmt / yang-data-grouping-stmt)
                              *data-def-stmt
                              [uses-yang-data-stmt]
                          "}") stmtsep

   // like 'uses-stmt', but with a different keyword
   uses-yang-data-stmt       = uses-yang-data-keyword sep identifier-ref-arg-str optsep
                         (";" /
                          "{" stmtsep
                              ;; these stmts can appear in any order
                              [when-stmt]
                              *if-feature-stmt
                              [status-stmt]
                              [description-stmt]
                              [reference-stmt]
                              *refine-stmt
                              *uses-augment-stmt
                          "}") stmtsep

   // like 'grouping-stmt', but with 'action' and 'notification' removed
   yang-data-grouping-stmt       = yang-data-grouping-keyword sep identifier-arg-str optsep
                         (";" /
                          "{" stmtsep
                              ;; these stmts can appear in any order
                              [status-stmt]
                              [description-stmt]
                              [reference-stmt]
                              *(typedef-stmt / yang-data-grouping-stmt)
                              *data-def-stmt
                          "}") stmtsep


   yang-data-keyword              = %s"yang-data"
   uses-yang-data-keyword         = %s"uses-yang-data"
   yang-data-grouping-keyword     = %s"yang-data-grouping"


How close to this can we get using an extension statement, so that a
future adoption to YANG will be as seamless as possible?

K.