IEC International ISO Standard ISO/IEC23415 First edition Information technology Data Format Description Language 2024-04 (DFDL) v1.0 Specification Referencenumber ISO/IEC23415:2024(en) @ISO/IEC 2024 IS0/IEC 23415:2024(en) Contents 7 Introduction 1.1 Why is DFDL Needed? 10 1.2 What is DFDL?. 10 1.2.1 Simple Example.. 10 1.3 What DFDL is not. 13 1.4 Scope of version 1.0 13 2 Overview of the Specification 15 3 Notational and Definitional Conventions 16 3.1 Glossary and Terminology . 16 3.2 Failure Types . 16 4 The DFDL Information Set (Infoset) 17 4.1 "No Value". 18 4.2 Information Items ... 18 4.2.1 Document Information Item .... 4.2.2 Element Information Items... 18 4.3 DFDL Information Item Order ... .19 4.4 DFDL Augmented Infoset .. 19 5 DFDL Schema Component Model .... .20 5.1 DFDL Simple Types... 20 5.2 DFDL Subset of XML Schema... 21 5.3 XSD Facets, min/maxOccurs, default, and fixed .. 5.3.1 MinOccurs, MaxOccurs 23 5.3.2 MinLength, MaxLength .... 5.3.3 Maxlnclusive, MaxExclusive, MinExclusive, Minlnclusive, TotalDigits, FractionDigits.. 5.34 Pattern ... 23 5.3.5 Enumeration Values . 23 5.36 Default.... 23 5.3.7 Fixed. 24 5.4 Compatibility with Other Annotation Language Schemas .. .24 6 DFDL Syntax Basics . 25 6.1 Namespaces . 25 6.2 The DFDL Annotation Elements .. 25 6.3 DFDL Properties ... 26 6.3.1 DFDL String Literals .. 28 6.32 DFDL Expressions. 32 6.3.3 DFDL Regular Expressions 32 6.3.4 Enumerations in DFDL 32 Syntax of DFDL Annotation Elements. 33 7.1 ComponentFormatAnnotations 33 7.1.1 Property Binding Syntax .. .34 7.1.2 Empty String as a Representation Property Value 35 7.2 dfdl:defineFormat - Reusable Data Format Definitions .36 7.2.1 Using/Referencing a Named Format Definition: The dfdl:ref Property . 7.2.2 Inheritancefor dfdl:defineFormat..... 7.3 The dfdl:defineEscapeScheme Defining Annotation Element... ..37 7.3.1 Using/Referencing a Named escapeScheme Definition .. .37 7.4 The dfdl:escapeScheme Annotation Element... .37 IS0/IEC 2024 - All rights reserved 3 IS0/IEC 23415:2024(en) 7.5 The dfdl:assert Statement Annotation Element... .38 7.5.1 Properties for dfdl:assert.. 7.6 The dfdl:discriminator Statement Annotation Element.. 7.6.1 Properties for dfdl:discriminator ... 7.7 DFDL Variable Annotations... 7.7.1 dfdl:defineVariable Annotation Element.. .43 7.7.2 The dfdl:newVariablelnstance Statement Annotation Element... 7.7.3 The dfdl:setVariable Statement Annotation Element. Property Scoping and DFDL Schema Checking . 8.1 Property Scoping . 47 8.1.1 Property Scoping Rules .. .47 8.1.2 Providing Defaults for DFDL properties 47 8.1.3 Combining DFDL Representation Properties from a dfdl:defineFormat. .48 R.1.4 Combining DFDL Properties from References 8.2 DFDL Schema Checking... ....51 R2.1 Schema Component Constraint: Unique Particle Attribution .... ...51 8.2.2 Optional Checks and Warnings ... .51 DFDL Processing Introduction.... .. 53 9.1 Parser Overview.... .53 9.1.1 Points of Uncertainty ... .53 9.1.2 Processing Error .. 54 91.3 Recoverable Error..... 9.2 DFDL Data Syntax Grammar 9.2.1 Nil Representation.. ..56 9.2.2 Empty Representation.. .56 9.23 Normal Representation ... .57 9.2.4 Absent Representation.. 57 925 Zero-length Representation ... 57 9.2.6 Missing.... 9.2.7 Examples of Missing and Empty Representation ... 9.2.8 Round Trip Ambiguities.. .58 9.3 Parsing Algorithm .. 9.3.1 Known-to-exist and Known-not-to-exist.. .59 932 Establishing Representation .. .60 9.3.3 Resolving Points of Uncertainty . .61 9.4 Element Defaults . 62 9.4.1 Definitions.... 9.4.2 Element Defaults When Parsing. 9.4.3 Element Defaults When Unparsing.. .64 9.5 Evaluation Order for Statement Annotations. .65 9.5.1 AssertsandDiscriminatorswithtestKind'expression'. .66 9.5.2 Discriminators with testKind 'expression' .66 9.5.3 Elements and setVariable .. .66 9.5.4 Controlling the Order of Statement Evaluation . 9.6 Validation..... 9.7 Unparser Infoset Augmentation Algorithm 10 Overview: Representation Properties and their Format Se