Hi Mike,
Thank you for the explanation. Yes, I see that is how Daffodil behaves.
But, but, but, ...
Does it make sense? If a data format specifies that instances contain 1 to 5
string values separated by forward slashes, then any of these instances should
be valid:
a
a/b
a/b/c
a/b/c/d
a/b/c/d/e
But you are saying that only the last instance is valid when
separatorSuppressionPolicy=never is also specified. You are saying that
instances must always contain 5 values (a zero-length string is a value):
a////
a/b///
a/b/c//
a/b/c/d/
a/b/c/d/e
To my mind, the constraints form a logical inconsistency. The constraints
minOccurs=1
maxOccurs=5
specifies instances contain 1 to 5 values
The constraint
separatorSuppressionPolicy=never
specifies instances must contain exactly 5 values.
Therefore, the constraints form a logical inconsistency, don't they?
/Roger
From: Beckerle, Mike <mbecke...@owlcyberdefense.com>
Sent: Tuesday, April 20, 2021 10:34 AM
To: users@daffodil.apache.org
Subject: [EXT] Re: Is separatorSuppressionPolicy=never meaningless?
The separatorSuppresssionPolicy 'never' used with a variable-length array,
means that there will always be separators for maxOccurs items. That is, the
separators are never suppressed even for optional item occurrences that are
absent.
So CSV-style data with separatorSuppressionPolicy 'never' and minOccurs 0,
maxOccurs 10 always requires 9 separators.
E.g.,
a/b/c///////
always 9 (for infix separator). Never any fewer, never any additional.
maxOccurs="unbounded" is not allowed with separatorSuppressionPolicy 'never'.
________________________________
From: Roger L Costello <coste...@mitre.org<mailto:coste...@mitre.org>>
Sent: Tuesday, April 20, 2021 9:44 AM
To: users@daffodil.apache.org<mailto:users@daffodil.apache.org>
<users@daffodil.apache.org<mailto:users@daffodil.apache.org>>
Subject: Is separatorSuppressionPolicy=never meaningless?
Hi Folks,
separatorSuppressionPolicy=never means separators are never omitted.
I have convinced myself that there are no instances that would ever raise an
error due to separatorSuppressionPolicy=never
Case #1: Suppose the schema specifies that instances must contain exactly 3
string data items, separated by forward slashes. There is no data for the 3rd
data item. Then instances must look like this:
a/b/
The instance cannot omit the last separator because the schema specifies
exactly 3 data items. So, separatorSuppressionPolicy=never has no effect in
this case.
Case #2: Suppose the schema specifies that instances contain 1 to 3 string data
items, separated by forward slashes. There is no data for the 3rd data item.
Then this is a valid instance:
a/b
Since there may be less than 3 data items, there are no omitted separators in
the instance. Again, separatorSuppressionPolicy=never has no effect in this
case.
I think those are the only two cases possible. In both cases
separatorSuppressionPolicy=never has no effect. I conclude that
separatorSuppressionPolicy=never is meaningless. I look forward to being proven
wrong.
/Roger
