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Unparser
This release contains only a parser. There is no unparser functionality in this release.
DFDL properties specific to unparsing are all unimplemented, and are generally ignored. These are:
- outputNewLine
- fillByte
- textPadKind
- textOutputMinLength
- generateEscapeBlock
- extraEscapedCharacters
- truncateSpecifiedLengthString
- outputValueCalc
Types
The following types are unsupported. Their use will cause schema definition errors. Properties specific to them are also unimplemented.
- decimal
- integer
- nonNegativeInteger
- hexBinary
- boolean
- date - unimplemented for dfdl:representation='binary'
- time - unimplemented for dfdl:representation='binary'
- dateTime - unimplemented for dfdl:representation='binary'
XML Schema Features
Of the subset of features in XSD that DFDL uses, these are unimplemented, and are ignored by the Daffodil system unless otherwise noted:
- fixed - property of element declarations
- default - property of element declarations
- attributeFormDefault (an attribute of the xs:schema element) - causes schema definition error (behaves as 'unqualified')
DFDL Features
These features of DFDL are broadly absent from the implementation in this release.
DFDL properties associated with these features may be entirely unrecognized or ignored.
- Defaulting of values for required elements
- All 'packed' binary number representation (packed, bcd, etc.)
- All 'zoned' text number representations.
- Rich text number format properties
- All bi-directional text
- unordered sequences
- floating elements in sequences
- external variables
- raw-byte entities
- validation
- alignment
- the 'type' component of the DFDL Infoset
- runtime-computed format properties (i.e., computing the value of dfdl:byteOrder at parse time based on data)
- IANA standard encodings other than: utf-8, utf-16BE, utf-16LE, utf-32BE, utf-32LE, and US-ASCII.
- expression language - qualified names are needed to reference elements. Unqualified elements do not work.
Daffodil-specific Features
These features are specified as part of the Daffodil API or Command-Line Interpreter, but are unsupported:
- save/reload of a compiled parser
Properties and Property Enumerations
The following properties or property enumeration values are unsupported.
Their use in a DFDL schema may cause a schema definition error, or they may simply be ignored.
- documentFinalTerminatorCanBeMissing="yes"
- utf16Width='variable'
- ignoreCase='yes'
- textNumberPattern
- textNumberCheckPolicy
- textNumberRoundingMode
- textNumberRounding
- textNumberRoundingIncrement
- textStandardGroupingSeparator
- textStandardDecimalSeparator
- textStandardExponentCharacter
- textStandardInfinityRep
- textStandardNaNRep
- textStandardZeroRep
- textStandardBase - only '10' supported
- textNumberRep="zoned"
- textZonedSignStyle
- decimalSigned
- textBooleanTrueRep
- textBooleanFalseRep
- textBooleanPadCharacter
- textBooleanJustification
- integerBooleanTrueRep
- integerBooleanFalseRep
- textBidi
- textBidiTextOrdering
- textBidiOrientation
- textBidiSymmetric
- textBidiTextShaped
- textBidiNumeralShapes
- alignment
- alignmentUnits
- leadingSkip
- trailingSkip
- lengthKind='delimited' when representation='binary'
- lengthKind='endOfParent'
- lengthKind='prefixed'
- prefixIncludesPrefixLength
- prefixLengthType
- binaryNumberRep (only "binary" supported, all packed are unsupported)
- binaryDecimalVirtualPoint
- binaryNumberCheckPolicy
- binaryPackedSignCodes
- binaryFloatRep="ibm390Hex"
- binaryCalendarRep
- binaryCalendarEpoch
- nilKind='literalCharacter'
- nilKind='logicalValue'
- useNilForDefault
- sequenceKind="unordered"
- floating="yes"
- separatorPolicy (TBD: is this accepted)
- choiceLengthKind="explicit"
- choiceLength
- occursCountKind='stopValue'
- occursStopValue
(TBD: mark them as ignored or SDE)
Functions
The following functions are unsupported in DFDL expressions:
- dfdl:contentLength
- dfdl:valueLength
Annotations
The following DFDL annotations are unsupported:
- dfdl:newVariableInstance
Some additional limitations:
- File sizes are limited to 4Gigabytes due to underlying Java libraries using type int for offsets.
- A Java 7 JVM is required as a number of its regular expression capabilities are passed through to Daffodil's DFDL implementation (as is required by the standard).
- An expression enclosed in { ... } cannot have whitespace before or after the brace {, } characters. To work around this limitation, use CDATA, that is, as the body of an element, wrap expressions like this: <![CDATA[{...expression...}]]>
- The expression language potentially accepts XPath constructs that are not allowed by DFDL. No attempt is made to identify such constructs and rule them out.
- The expression language is based on XPath 1.0, not XPath 2.0 as required by the spec.
There is a list of bugs available in our JIRA tracking system.