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

Format

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

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.