RPSL question

Hello Frank,

> I'm writting a Perl RPSL parser module and have a understanding
> problem with part 2 "RPSL Names, Reserved Words, and Representation"
> page 5 of RFC 2622 ;-(

Good luck to you :)

>   "A value of an attribute may also be a list of one of these types.  A
>    list is represented by separating the list members by commas ",".
>    For example, "AS1, AS2, AS3, AS4" is a list of AS numbers.  Note that
>    being list valued and being multiple valued are orthogonal.  A
>    multiple valued attribute has more than one value, each of which may
>    or may not be a list.  On the other hand a single valued attribute
>    may have a list value."
>
> Ok, a multiple attribute value can be a single value or a 'comma list'
> of values. But the last sentence confused me - "a single valued
> attribute may have a list value" ?
>
> Means that "aut-num: AS123, AS456, ..." is a correct attribute of
> an aut-num object ?!?!

First let me define 'list value' and 'multiple/single valued' attributed.
'List value' refers to the attribute value (ie, can you have a list of values
seperated by a comma as the attribute value).  'multiple/single valued'
attributes specify if the attribute can appear in the object more than once.
For example, the 'import' and 'export' attributes can appear more than
once in the aut-num object, so 'import' and 'export' are multiple valued
attributes.  'aut-num' can only appear once in the 'aut-num' class/object
so it is single valued.

'mnt-by' is an example of a list valued attribute since you can specify a
list of maintainers seperated by a comma.

> Means that "aut-num: AS123, AS456, ..." is a correct attribute of
> an aut-num object ?!?!

No, since 'aut-num' is not defined as list valued.  The aut-num attribute
is also defined as single valued (so it cannot appear more than once
in the object).

Hope this helps.

--jerry