Following is the resolution from action
139.
An errata document accompaniment to
the DFDL 1.0 specification is under production and this will be added to
it.
Regards
Steve Hanson
Architect, Data Format Description Language (DFDL)
Co-Chair, OGF
DFDL Working Group
IBM SWG, Hursley, UK
smh@uk.ibm.com
tel:+44-1962-815848
----- Forwarded by Steve
Hanson/UK/IBM on 05/07/2011 18:26 -----
WG resolution for action 139
a) In-scope delimiters
Clarification: Using lengthKind 'explicit',
'implicit', 'prefixed' or 'pattern' means that delimiter scanning is turned
off and in-scope delimiters are not looked for within or between elements.
b) Policing a physical constraint without
terminating a parse
The example cited was using a dfdl:assert
to police a physical length constraint when lengthKind is 'delimited'.
Addition:
- A new failure type is introduced,
'Recoverable Error', after which the parser will continue.
- Importantly, it does not cause backtracking
to take place when speculating.
- It can be raised via a new enum attribute
on dfdl:assert called 'failureType' - see below.
- An error occurring during evaluation
of a dfdl:assert remains a Processing Error.
- All existing stated Processing Errors
remain as such.
- Discriminators remain unchanged.
- The issuing of Recoverable Errors
is independent of whether validation is enabled.
| Property Name
| Description
|
| failureType
| Enum (optional)
Valid values are 'processingError', 'recoverableError'.
Default value is 'processingError'.
Specifies the type of failure that occurs
when the dfdl:assert is unsuccessful.
When 'processingError', a processing error
is raised.
When 'recoverableError', a recoverable error
is raised.
Annotation: dfdl:assert |
The WG believe the new failure type
is genuinely useful going forward as it allows the parser or unparser to
continue in situations where it was unable to do so.
The WG considered extending Validation
Error to cover this, but the spec is quite clear that these are logical
checks performed on the infoset and the behaviour of the DFDL processor
is unspecified, so it seemed best not to change this and to introduce a
new failure type.
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