[jira] Commented: (DIRLDAP-52) The Antlr grammar for Subtree Specification (RFC 3672) does not handle Separators correctly

["Ersin Er (JIRA)" <di...@incubator.apache.org>]

    [ http://issues.apache.org/jira/browse/DIRLDAP-52?page=comments#action_12320934 ] 

Ersin Er commented on DIRLDAP-52:
---------------------------------

I've fixed the issues mentioned. The patch attached includes a grammar update and minor cleanup for related files. The grammar got somewhat complicated but this was required to solve SEP token issue with antlr. I should thank to Emmanuel Lécharny for his great advices.

> The Antlr grammar for Subtree Specification (RFC 3672) does not handle Separators correctly
> -------------------------------------------------------------------------------------------
>
>          Key: DIRLDAP-52
>          URL: http://issues.apache.org/jira/browse/DIRLDAP-52
>      Project: Directory LDAP
>         Type: Bug
>   Components: Common
>     Versions: 0.9.3
>     Reporter: Ersin Er
>  Attachments: SubtreeSpecificationInvalidSeperatorHandlingBugFix.patch
>
> The Antlr grammar for Subtree Specification (RFC 3672) handles SP token as ' ' (single space) and MSP as (' ')+. The SEP token is handled as ',' everywhere. However, "RFC 3642" defines them as follows:
> "
> 3.  Separators
>    Certain separators are commonly used in constructing equivalent ABNF
>    for SET and SEQUENCE types.
>       sp  =  *%x20  ; zero, one or more space characters
>       msp = 1*%x20  ; one or more space characters
>       sep = [ "," ]
>    The <sep> rule is used in the ABNF description of the encoding for
>    ASN.1 SET or SEQUENCE types where all the components are either
>    OPTIONAL or DEFAULT.  It encodes to an empty string if and only if
>    the immediately preceding character in the encoding is "{", i.e., it
>    is only empty for the first optional component actually present in
>    the SET or SEQUENCE value being encoded.
> "
> So,
>  SP token should be handled as Zero Or More Spaces Characters which is (' ')*,
>  MSP token should be handled as OneOr More Spaces Characters which is (' ')+,
> and
> SEP should be handled in a way that it should match empty string when it comes just after a "{" token. (This one is an interesting problem.)
> I'm working on this issue now and will submit a patch soon. Comments are welcome.
> The grammar file considered is:
> http://svn.apache.org/viewcvs.cgi/directory/shared/ldap/trunk/common/src/antlr/subtree-specification.g?rev=265643&view=markup

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