C Context Components

The tables in this section describe the scope (range of applicability) of the various components in a module's static context and dynamic context.

C.1 Static Context Components

The following table describes the components of the static context. For each component, "global" indicates that the value of the component applies throughout an XPath expression, whereas "lexical" indicates that the value of the component applies only within the subexpression in which it is defined.

Static Context Components
Component Scope
XPath 1.0 Compatibility Mode global
Statically known namespaces global
Default element/type namespace global
Default function namespace global
In-scope schema types global
In-scope element declarations global
In-scope attribute declarations global
In-scope variables lexical; for-expressions, let-expressions, and quantified expressions can bind new variables
Context item static type lexical
Statically known function signatures global
Statically known collations global
Default collation global
Base URI global
Statically known documents global
Statically known collections global
Statically known default collection type global

C.2 Dynamic Context Components

The following table describes how values are assigned to the various components of the dynamic context. All these components are initialized by mechanisms defined by the host language. For each component, "global" indicates that the value of the component remains constant throughout evaluation of the XPath expression, whereas "dynamic" indicates that the value of the component can be modified by the evaluation of subexpressions.

Dynamic Context Components
Component Scope
Context item dynamic; changes during evaluation of path expressions and predicates
Context position dynamic; changes during evaluation of path expressions and predicates
Context size dynamic; changes during evaluation of path expressions and predicates
Variable values dynamic; for-expressions, let-expressions, and quantified expressions can bind new variables
Current date and time global; must be initialized
Implicit timezone global; must be initialized
Available documents global; must be initialized
Available node collections global; must be initialized
Default collection global; overwriteable by implementation
Available URI collections global; must be initialized
Default URI collection global; overwriteable by implementation