Primary expressions

Primary expressions are basic primitives of the language.

Syntax


primary-expression

|--+-literal------------------+---------------------------------|
   +-variable-reference-------+   
   +-parenthesized-expression-+   
   +-context-item-expression--+   
   '-function-call------------'

Literals
XQuery supports two kinds of literals: numeric literals and string literals.
Variable references in XQuery
A variable reference is a QName that is preceded by a dollar sign ($). When an XQuery expression is evaluated, each variable reference resolves to the value of the expression that is bound to the variable.
Parenthesized expression
Parentheses can be used to enforce a particular order of evaluation in expressions that contain multiple operators.
Context item expressions
A context item expression consists of a single period (.). A context item expression evaluates to the item that is currently being processed, which is known as the context item. The context item can be either a node or an atomic value.
Function calls in XQuery
XQuery supports calls to built-in XQuery functions.

Parent topic: Expressions