Re: [yang-doctors] canonical order question

[Martin Björklund <[e-mail]>]

Hi,

Scott Mansfield <scott.mansfield=[e-mail]> wrote:
> I looked through the mail archive and the pyang issues list on git, so
> apologies if I missed this...
> 
> However,
> 
> Clause 14 of RFC 7950 says this...
>    body-stmts          = *(extension-stmt /
>                            feature-stmt /
>                            identity-stmt /
>                            typedef-stmt /
>                            grouping-stmt /
>                            data-def-stmt /
>                            augment-stmt /
>                            rpc-stmt /
>                            notification-stmt /
>                            deviation-stmt)
> 
> 
> But when I use pyang and the -yang-canonical switch, the output I get
> has the notification statements before the augment statements.  Is
> this ok?  Am I reading the ABNF incorrectly?

RFC 7950 says:

   The ABNF grammar
   [RFC5234] [RFC7405] defines the canonical order.

And then the grammar has for example:

   linkage-stmts       = ;; these stmts can appear in any order
                         *import-stmt
                         *include-stmt

So, the ABNF says that "import" comes before "include" which means
that this is the canonical order.

But for body-stmts, the ABNF allows any order of the child
statements.  Hence the canonical order also allows any order.


/martin




> 
> I have attached the before and after for information.
> ieee802-dot1q-rstp.yang is the original which has notifications after
> the augment statement.  I then ran it though pyang with -f yang
> -yang-canonical and put the result in ieee802-dot1q-rstp-canon.yang,
> but now the notification statements were moved before the augment.
> Just trying to understand what the canonical order is.
> 
> Many thanks for the help and experience!
> Regards,
> -scott.
> 
> 
> 
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