The W3C XQuery Working Group has also published the first draft of XML Query (XQuery) 1.1 Requirements. Here are the requirements:
XQuery 1.1 MUST be backward compatible.
Every valid XQuery 1.0 expression MUST be valid in XQuery 1.1 and it MUST evaluate to the same result.
XQuery 1.1 MUST be compatible with XQuery 1.0 extensions developed by the XML Query Working Group, including XQuery Update Facility and XQuery 1.0 and XPath 2.0 Full-Text.
XQuery 1.1 MUST include a language facility to specify value-based grouping.
XQuery 1.1 MUST provide a mechanism to process errors raised by an expression and to return an alternative value.
This MAY be implemented by introducing a try-catch expression.
XQuery 1.1 MUST include additional library functions or an equivalent mechanism to perform formatting of numeric values.
It SHOULD be similar to the functionality provided in XSLT 2.0, such as by function format-number().
XQuery 1.1 MUST include additional library functions or an equivalent mechanism to perform formatting of date and time values.
It SHOULD be similar to the functionality provided in XSLT 2.0, such as by functions format-date(), format-time(), format-dateTime().
XQuery 1.1 MUST have a mechanism to specify default values for external variables.
XQuery 1.1 MUST provide a way to denote that an external function is non-deterministic.
XQuery 1.1 SHOULD provide a facility for positional grouping of items in a sequence according to specified partitioning conditions.
XQuery 1.1 SHOULD provide a way to iterate over a sequence by several values at a time.
XQuery 1.1 SHOULD provide a mechanism to associate ordinal numbers with the items returned by a FLWOR expression.
XQuery 1.1 SHOULD allow dynamic creation of namespace bindings.
XQuery 1.1 SHOULD have a mechanism to specify serialization parameters in the query prolog.
XQuery 1.1 SHOULD support creation of a reference to an existing node having the following properties:
a) the reference could be included in a constructed element
b) the reference can be dereferenced, returning the original node with the original node id.
XQuery 1.1 SHOULD provide additional mechanisms to specify joins between sequences. A possible approach would be to add an "outer-for" clause to the FLWOR expression to specify variable binding which is guaranteed to be bound to an empty sequence if there are no other bindings generated.
XQuery 1.1 SHOULD allow explicit type declaration for the context item.
XQuery 1.1 SHOULD support new data types introduced in XML Schema 1.1.
XQuery 1.1 MAY provide an ability to pass a function as an argument to another function and to invoke a function that has been passed as an argument.
XQuery 1.1 MAY also provide the ability to define anonymous functions e.g., lambda expressions.
XQuery 1.1 MAY add a language extension to the node constructors to specify, in a compact notation, that a node should be constructed only if its typed value would not be an empty sequence or if it would satisfy some other condition.
XQuery 1.1 MAY provide a mechanism to validate an element or document node with respect to a global named type or against non-global element declarations or types.
XQuery 1.1 MAY provide a mechanism to validate an element or document node against a named schema without importing the schema.
XQuery 1.1 MAY provide a way to compare the type of an expression to the type of another expression without exposing the type itself.
XQuery 1.1 MAY relax the restrictions on the module import feature relating to forward references and circular imports.
XQuery 1.1 MAY provide a normative way to invoke external functions and modules that are not implemented in XQuery, such as functions defined as web services or XSLT functions and templates.
XQuery 1.1 MAY extend static typing rules
The W3C XQuery Working Group has also published the final 1.0 versions of XML Query (XQuery) Requirements and XML Query Use Cases.
Finally the XQuery working group has posted the first draft of XQuery Scripting Extension 1.0 Requirements. "This document describes the requirements for the XQuery Scripting Extensions. XQuery [XQuery 1.0] is a functional language that is Turing-complete and well suited to write code that ranges from simple queries to complete applications. However, some categories of applications are more easily implemented by combining XQuery capabilities with some imperative features, such as the ability to explicitly manage internal states. The same issue stands for XQuery enriched with the [XQuery Update Facility] (hereafter, XQuery With Updates). The scripting extension is intended to overcome this problem, and allow programmers to write such applications without relying on embedding XQuery into an external language."
