XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition (806 page)

Axis (XPath)

An axis is a direction of travel through the
tree
. Starting from a particular
context node
, an axis defines a list of
nodes
reached from that origin. For example, the
ancestor axis
returns the parent, grandparent, and so on up to the root of the tree, while the
following sibling
axis returns all the
nodes
that appear after the
context node
and share the same parent.

Base URI (XPath)

Every
node
has an associated base URI. For an element, this is the absolute URI of the XML external
entity
containing the element's start and end
tags
(most often, of course, this will be the document entity). For other node types, it is defined by reference to an associated
element node
, typically its parent. The base URI of an element can also be set explicitly by using the
xml:base
attribute. The base URI of a node is used when expanding a relative URI defined in that node; for example, a relative URI in an
href
attribute is considered to be relative to the base URI of the parent element.Every XPath expression also has a base URI defined as part of its
static context
. For an XPath expression contained in a
stylesheet
, this is the base URI of the stylesheet element containing the XPath expression. In non-XSLT contexts, it's up to the host environment to specify a base URI for the expression.

Boolean (XPath)

One of the allowed data
types
for the value of an XPath expression. It takes the value true or false.

Built-In Template Rule (XSLT)

A
template rule
that is not explicitly defined in the
stylesheet
, but that is implicitly available to process a
node
if there is no explicit template rule that matches it.

Built-In Type (Schema)

The XML Schema specification defines a number of built-in
simple types
that are available for use, without any need to declare them in a schema. These include 19
primitive types
(such as
xs:string
and
xs:date
), 20 built-in derived atomic types (including
xs:integer
and
xs:ID
), and 3 built-in
list types
(
xs:NMTOKENS
,
xs:IDREFS
, and
xs:ENTITIES
).

Cast (XPath)

An
expression
that converts an
atomic value
of one
type
to an atomic value of a different type.

CDATA Section (XML)

A sequence of characters in an XML document enclosed between the delimiters
![CDATA[
and
]]
; within a CDATA section all characters represent text content rather than markup, except for the sequence
]]
.

Character Map (XSLT)

A rule for translating characters in a
result tree
into different characters (or strings) in the serialized output.

Character Reference (XML)

A representation of a character using its decimal or hexadecimal Unicode value; for example,

or
↤
. Normally used for characters that are difficult or impossible to enter directly at the keyboard. Character references appear in lexical XML documents, but in the
XDM
data model, they are replaced by the characters that they represent.

Child Axis (XPath)

The child axis selects all the immediate children of the
context node
. These can include
elements
,
text nodes
,
comments
, and
processing instructions
, but not
attributes
or
namespace nodes
. This is a
forwards axis
.

Codepoint (Unicode)

A numeric value identifying a Unicode character.

Codepoint Collation (XPath)

A
collation
that compares and sorts strings strictly according to the numeric values of the
codepoints
making up the characters of the string.

Collation (XPath)

A set of rules for comparing strings. A collation can be used to decide whether two strings are equal, to decide how they should be ordered, and to decide whether one string is a substring of another. Different collations are needed to satisfy the needs of different languages or different applications. In XPath and XSLT a collation is identified by a
URI
. Except for the
codepoint collation
, the URIs used to identify collations are defined by the implementation.