XQuery Annotations and Optional Features Namespace Document

1 Introduction

This document describes the namespace http://www.w3.org/2012/xquery defined by the [XQuery 3.1] specification (March 2017 version). This namespace is identified in this document by the namespace prefix qfa:, but that is not a predefined namespace prefix; this namespace is not defined by an XML Schema. For updated information, please refer to the latest version of the [XQuery 3.1] specification.

This document describes the intended uses of this namespace. The W3C reserves the right to define names in this namespace in the future. [XQuery 3.1] is the only specification that may amend this namespace.

This document contains a directory of links to related resources, using RDDL (as defined in [Resource Directory Description Language (RDDL)]).

It is GRDDL-enabled (as defined in [Gleaning Resource Descriptions from Dialects of Languages (GRDDL)]), that is to say that a GRDDL-compliant processor can extract useful RDF (as defined in [Resource Description Framework (RDF): Concepts and Abstract Syntax]) representations of the information contained herein.

2 XQuery Annotations

[XQuery 3.1] provides syntax to define annotations on function declarations and variable declarations. Two annotations are defined in [XQuery 3.1]. Application and query authors may define additional annotations, as may XQuery implementations. Those additional applications belong, by default, to the http://www.w3.org/2012/xquery namespace (but may be defined in other namespaces as well).

```
%public
```
Public variables and public functions are accessible to module import. (Variables declared without either a %public or %private annotation are, by default, public variables.)
```
%private
```
Private variables and private functions are hidden from module import.

3 XQuery Features

[XQuery 3.1] defines two features that are used to control the use of other, optional features.

```
qfa:require-feature
```
identifies features that must be enabled for the module in which the option declaration occurs; if any of these QNames corresponds to a feature that the implementation does not support, a static error is raised.
```
qfa:prohibit-feature
```
identifies features that must not be enabled in the module in which the option declaration occurs; if any of these QNames corresponds to a feature that the implementation supports, it must disable that feature.

There are several optional features defined in [XQuery 3.1] for which these two features have meaning:

```
qfa:schema-aware
```
```
qfa:static-typing
```
```
qfa:module
```
```
qfa:serialization
```
```
qfa:higher-order-function
```

4 Normative References

XQuery 3.1: XQuery 3.1 (21 March 2017 version)

This document describes the usage of this namespace. The W3C reserves the right to define names in this namespace in the future. [XQuery 3.1] is the only specification that is permitted to amend this namespace. It may, however, be augmented by other specifications that define XQuery 3.1 extensions.

5 Non-Normative References

Resource Directory Description Language (RDDL): Resource Directory Description Language (RDDL) (4 July 2007)
Gleaning Resource Descriptions from Dialects of Languages (GRDDL): Gleaning Resource Descriptions from Dialects of Languages (GRDDL) (Recommendation of 11 September 2007)
Resource Description Framework (RDF): Concepts and Abstract Syntax: Resource Description Framework (RDF): Concepts and Abstract Syntax (Recommendation of 10 February 2004)