[DFDL-WG] regex free-spacing mode

[Mike Beckerle]

To clarify, errata v13 has this in the table for erratum 3.29 in the list
of non-portables:

(?imsx-imsx:X)

X, as a non-capturing group with the
given flags. Note that the flags i,s,m,x
are valid, but appending :X to the flag is
not.

Java 7 only

I interpret this as meaning that only the so-called modifier-span notation
(the : suffix) is disallowed, but not just plain (?x), but I wanted to be
sure that was the correct interpretation.


On Wed, Jun 26, 2013 at 1:13 PM, Mike Beckerle <mbeckerle.dfdl at gmail.com>wrote:

>
> I wrote this complicated regex today and it works in Daffodil.
>
> Question is this. Is the (?x) which turns on regex free-spacing mode,
> officially supported in DFDL?
>
> You can see from below that it is VERY desirable that it works.....
>
>   <xs:simpleType name="frontMatterType">
>       <xs:annotation>
>         <xs:appinfo source="http://www.ogf.org/dfdl/">
>           <dfdl:simpleType lengthKind="pattern" terminator="%FF;">
>
>             <dfdl:property name="lengthPattern"><![CDATA[(?x) # regex free
> spacing mode
>             #
>             # match the front matter of the document
>             #
>             .{1,8192}?                # up to 8K of front matter content
>             #
>             # front matter ends at the first message description page
>             #
>             (?=                       # lookahead (followed by but not
> including...)
>               \f                      # a formfeed character
>               (?> \s | \x08 ){1,100}? # whitespace or backspace (x08)
>               MESSAGE\ DESCRIPTION\r  # this literal text
>               \s{1,100}?              # up to 100 whitespaces
>               -{19}\r                 # exactly 19 hyphens and a CR
>             )                         # end lookahead
>             ]]></dfdl:property>
>
>            </dfdl:simpleType>
>         </xs:appinfo>
>       </xs:annotation>
>       <xs:restriction base="xs:string" />
>     </xs:simpleType>
>
> --
> Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
> www.tresys.com
>
>


-- 
Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
www.tresys.com
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