XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition (260 page)

BOOK: XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition

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Format

name = qname

select? = expression

as? = sequence-type>

Position

The

element may appear either as a top-level declaration (that is, as a child of the

element), or as an instruction within a sequence constructor.

Attributes

Name	Value	Meaning
name mandatory	Lexical QName	The name of the variable.
select optional	Expression	An expression that is evaluated to give the value of the variable. If omitted, the value is determined from the contents of the element.
as optional	SequenceType	Declares the type of the variable. A type error occurs if the value of the expression cannot be converted to this type using the standard type conversions defined below (page 505). In addition, the presence of this attribute on an element with nonempty content indicates that the result of evaluating the contained sequence constructor is to be used directly as the value of the variable, rather than being used to construct a temporary document.

The
SequenceType
construct is described in Chapter 11.

Content

An optional sequence constructor. If a
select
attribute is present, the

element must be empty.

Effect

An

element may appear either at the top level of the stylesheet (in which case it declares a global variable) or as an instruction within a sequence constructor (in which case it declares a local variable).

The Name of the Variable

The name of the variable is defined by a lexical QName. Normally, this will be a simple name such as
city
or
total-sales
, but it may be a name qualified with a prefix, for example
my:value
. If it has a prefix, the prefix must correspond to a namespace that is in scope at that point in the stylesheet. Two variables,
my:value
and
your:value
, have matching names if the prefixes
my
and
your
refer to the same namespace URI. If the name has no prefix, it has a null namespace URI—it does not use the default namespace URI.