Banibrata Dutta wrote:

Thanks for the clarification Lev.

I saw that the 3GPP MAP spec had a "NULL" abstract data-type. Checked the
list of primitive data-types, didn't find it there, and a quick (but not yet
thorough) search of the MAP spec itself, i couldn't find it's defn., so
asked!

NULL is defined in X.680, #23.

cheers,
- bani



-----Original Message-----
From: Lev Walkin [mailto:[EMAIL PROTECTED] Sent: Monday, April 11, 2005 6:53 PM
To: Banibrata Dutta
Cc: [email protected]
Subject: Re: [ASN1] question about "..." & NULL


Banibrata Dutta wrote:


Hi,

Could someone explain as to if the "..." can be followed by

a data field ?

e.g.

My-Type ::= SEQUENCE {
 my-Field-1        MY-FIELD-1,
 my-Field-2        MY-FIELD-2,
 ...,
 my-Field-X        MY-FIELD-X  -- can my-Field-X follow "..." ??
}

or must it be... ?

Yes, my-Field-X may follow the dots.

Moreover, one could write something like this:

        My-Type ::= SEQUENCE {
                my-Field-1      MY-FIELD-1,
                my-Field-2      MY-FIELD-2,
                ...,
                my-Field-X      MY-FIELD-X,
                ...,
                my-Field-Y      MY-FIELD-Y
        }

that is, two three blocks of sequence members, separated by two ellipses.

This is described in X.680, #24.1, or in Olivier Dubuisson's book,
"ASN.1 Communication between heterogeneous systems", #12.2.2(3).


My-Type ::= SEQUENCE {
my-Field-1 MY-FIELD-1,
my-Field-2 MY-FIELD-2,
...,
my-Field-X MY-FIELD-X OPTIONAL -- is

"OPTIONAL" mandatory

here ??
}

OPTIONAL is not mandatory, yet it may be explicitly given.


also, is NULL, a predefined type ?

please clarify.


-- Lev Walkin [EMAIL PROTECTED]





--
Lev Walkin
[EMAIL PROTECTED]
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