Thanks Mike.
Okay, the alternatives in a pattern facet must be sorted longest-to-shortest.
What if the alternatives are expressed in an enumeration facet, e.g.,
<simpleType>
<restriction base=”string”>
<enumeration value=”abc”/>
<enumeration value=”abcd”/>
</restriction>
</simpleType>
Do I also need to sort the enumeration values in longest-to-shortest order?
/Roger
From: Mike Beckerle <mbecke...@apache.org>
Sent: Friday, August 5, 2022 5:50 PM
To: users@daffodil.apache.org
Subject: [EXT] Re: Do I need to sort the xs:pattern regex alternatives
longest-to-shortest?
Yes you do. All the regex engines I know are greedy.
Besides regexs just being fussy, this is the main reason DFDL has a delimiter
language that is it's own thing. Because the delimiters are specified in
different places, not all together as in a regex. Hence the user has no
opportunity to sort longest to shortest, so DFDL delimiters match all the
possible delimiters that can appear at a point with longest match preferred.
Il Ven 5 Ago 2022, 1:54 PM Roger L Costello
<coste...@mitre.org<mailto:coste...@mitre.org>> ha scritto:
Hi Folks,
Recall that when using dfdl:lengthPattern you must specify its regex
alternatives longest-to-shortest. For example, if you specify this:
dfdl:lengthPattern="abc|abcd"
then you will get a "left over data" error message.
So you must sort the alternatives in longest-to-shortest order. That is a
hassle.
The "-V limited" option changes things. It enables me to abandon
dfdl:lengthPattern and instead use the XSD pattern facet:
<simpleType>
<restriction base="string">
<pattern value="abc|abcd"/>
</restriction>
</simpleType>
Question: Do I need to sort the pattern facet alternatives in
longest-to-shortest order? I am hoping the answer is "no".
/Roger
