Hi Steve,
No, that is not a viable solution. As you observed, it doesn't scale. For a
fixed length field of 10, we would need to specify something like 10-factorial
alternatives (or is it 2^^10 alternatives?) in dfdl:nilValue.
/Roger
-----Original Message-----
From: Steve Lawrence <slawre...@apache.org>
Sent: Wednesday, August 10, 2022 8:25 AM
To: users@daffodil.apache.org
Subject: [EXT] Re: Conflicting requirements: fixed length field, nillable, some
enumeration values shorter than the required length
I'm not sure I love this possibles solution, and it doesn't scale very
well, but what about something like this:
<element name="field" type="xs:string" nillable="true"
dfdl:lengthKind="explicit"
dfdl:length="3"
dfdl:textStringJustification="left"
dfdl:textTrimKind="padChar"
dfdl:textPadKind="padChar"
dfdl:textStringPadCharacter="%SP;"
dfdl:nilKind="literalValue"
dfdl:nilValue="- %SP;- %SP;%SP;-" />
So the field is left-justified and right-padded with spaces. Left padded
spaces are not trimmed, so a field like " A " will show up in the
infoset with the left space and fail validation. And the nilValue is set
to all the combinations of the nil character preceded with a space.
Like I said, this doesn't scale because you need N nilValues for a
string of length N. And this scala at all for delimited length fields
where you don't know the length of the field, unless you just add a
bunch of nilValues up to some size.
If we had something like %SP*; (similar to how we have %WSP*;), then the
nilValue could just be "%SP*;-" and this would scale without issue, and
work for both fixed length and delimited length fields. I believe %SP*;
has come up in the past, so this might be another argument to added it.
On 8/10/22 7:54 AM, Roger L Costello wrote:
> Thanks Mike. I implemented your approach. It fails to detect invalid input.
> Let
> me explain.
>
> Input specifications:
>
> * Fixed length field (3)
> * Nillable, hyphen is the nil value, the hyphen may be anywhere within the
> 3
> character field
> * Values must be left-justified
>
> Here are examples of valid inputs:
>
> …/AB /…
>
> …/ABC/…
>
> …/- /…
>
> .../ - /…
>
> …/ -/…
>
> Your solution permits this input (I tested it, Daffodil gives no error or
> warning):
>
> …/ AB/…
>
> Notice that the value is right-justified. That is invalid.
>
> /Roger
>
> /Roger
>
> *From:* Mike Beckerle <mbecke...@apache.org>
> *Sent:* Monday, August 8, 2022 3:58 PM
> *To:* users@daffodil.apache.org
> *Subject:* [EXT] Re: Conflicting requirements: fixed length field, nillable,
> some enumeration values shorter than the required length
>
> So I think your requirements are this:
>
> * fixed length 5
>
> * the hyphen nil indicator may have spaces around it
>
> * canonical form is left justified for "-" or any value.
>
> This is the best I could do. I had to surround the nillable element with
> another
> element so as to get left-justification by way of filling of the unused region
> of a complex type, with fillByte which is %SP;.
>
> If you want center justified hyphens for the nil case and left-justified
> strings
> for the value case, then I think it's not possible to model this without using
> separate elements for the nil and value. (That solution not shown here.)
>
> <*element *name*="Foo"
> *dfdl:length*="5"
> *dfdl:lengthKind*="explicit"
> *dfdl:terminator*="/"
> *dfdl:fillByte*="%SP;"* >
> /<!--
> The above achieves canonical unparse
> as left-justified fixed length because
> the fillByte will be used to fill unused
> space on the right.
>
> This only works for fixed length left-justified data.
> If this was right-justified, this trick would not work.
> -->
> /<*complexType* >
> <*sequence* >
> /<!--
> The below achieves trimming of spaces either side,
> but only when parsing. Nothing is added when unparsing.
> -->
> /<*element *name*="value" *nillable*="true"
> *dfdl:nilValue*="-"
> *dfdl:lengthKind*="delimited"
> *dfdl:textStringJustification*="center"
> *dfdl:textTrimKind*="padChar"
> *dfdl:textPadKind*="none"* >
> <*simpleType* >
> <*restriction *base*="xs:string"* >
> <*enumeration *value*="AB"*/>
> <*enumeration *value*="ABC"*/>
> </*restriction* >
> </*simpleType* >
> </*element* >
> </*sequence* >
> </*complexType* >
> </*element* >
>
> The TDML file I created for this has these tests in it showing that this
> works:
>
> <parserTestCase name="foo1" root="Foo" model="s" roundTrip="onePass">
> <document>- /</document>
> <infoset>
> <dfdlInfoset>
> <ex:Foo xmlns=""><value xsi:nil="true"/></ex:Foo>
> </dfdlInfoset>
> </infoset>
> </parserTestCase>
>
> <parserTestCase name="foo2" root="Foo" model="s" roundTrip="twoPass">
> <document> - /</document>
> <infoset>
> <dfdlInfoset>
> <ex:Foo xmlns=""><value xsi:nil="true"/></ex:Foo>
> </dfdlInfoset>
> </infoset>
> </parserTestCase>
>
> <parserTestCase name="foo3" root="Foo" model="s" roundTrip="twoPass">
> <document> AB /</document>
> <infoset>
> <dfdlInfoset>
> <ex:Foo xmlns=""><value>AB</value></ex:Foo>
> </dfdlInfoset>
> </infoset>
> </parserTestCase>
>
> <parserTestCase name="foo4" root="Foo" model="s" roundTrip="onePass">
> <document>AB /</document>
> <infoset>
> <dfdlInfoset>
> <ex:Foo xmlns=""><value>AB</value></ex:Foo>
> </dfdlInfoset>
> </infoset>
> </parserTestCase>
>
> On Mon, Aug 8, 2022 at 10:22 AM Roger L Costello <coste...@mitre.org
> <mailto:coste...@mitre.org>> wrote:
>
> Hi Mike,
>
> I gave your suggested approach a try. It failed.
>
> With this input:
>
> …/AB /…
>
> it works.
>
> With this input:
>
> …/ - /…
>
> it fails, producing this error:
>
> [error] Validation Error: Foo failed facet checks due to: facet
> enumeration(s): AB|ABC
>
> Further, even if the approach were to work with this example where the
> field
> length is 3, it would be an untenable approach for longer fixed fields.
> For
> example, if the field length was 10, then the nilValue would need
> something
> like 10-factorial whitespace-separated values.
>
> Do you have another suggested approach?
>
> /Roger
>
> *From:* Mike Beckerle <mbecke...@apache.org
> <mailto:mbecke...@apache.org>>
> *Sent:* Monday, August 8, 2022 9:38 AM
> *To:* users@daffodil.apache.org <mailto:users@daffodil.apache.org>
> *Subject:* [EXT] Re: Conflicting requirements: fixed length field,
> nillable,
> some enumeration values shorter than the required length
>
> I would try making the nilValue "%SP;-%SP; -". That is two separate
> possibilities for nilValue, one is space-hyphen-space, the other just
> hyphen. (It's a whitespace-separated list of nil values tokens.)
>
> The first one will be used for unparsing. Both will be tried for parsing.
>
> That along with justification left might work.
>
> On Mon, Aug 8, 2022 at 8:01 AM Roger L Costello <coste...@mitre.org
> <mailto:coste...@mitre.org>> wrote:
>
> Hi Folks,
>
> I have an input field that is fixed length (3). If there is no data,
> the
> field is to be populated with a hyphen (of course, it must be padded
> with spaces to the required length). The schema has a simpleType with
> enumeration facets. Some enumeration values are less than the
> required
> length.
>
> Here's how I specify the field:
>
> <xs:element name="Foo"
> nillable="true"
> dfdl:nilKind="literalValue"
> dfdl:nilValue="-"
> dfdl:lengthKind="explicit"
> dfdl:length="3"
> dfdl:textTrimKind="padChar"
> dfdl:textPadKind="padChar"
> dfdl:textStringPadCharacter="%SP;"
> dfdl:textStringJustification="center">
> <xs:simpleType>
> <xs:restriction base="xs:string">
> <xs:enumeration value="AB"/>
> <xs:enumeration value="ABC"/>
> </xs:restriction>
> </xs:simpleType>
> </xs:element>
>
> Notice dfdl:textStringJustification="center" which is fine for the
> nillable value (hyphen) but not for a regular value such as AB which
> should be left justified. As the schema is, the input could contain
> this
> (assume slash separators):
>
> .../ AB/...
>
> which is incorrect.
>
> So, there are conflicting requirements: the nillable value needs
> dfdl:textStringJustification="center" whereas the normal values need
> dfdl:textStringJustification="left". What to do about this?
>
> /Roger
>
