Name
if — If the boolean value is true then calculates one expression, otherwise calculates another expression.
Synopsis
any if
( |
test boolean , |
| then_branch any , | |
else_branch any ); |
Description
This function calculates the value of test argument. If the value is true,
the function calculates the then_branch expression and returns
its value. If the value is false, the function calculates the
else_branch expression and
returns its value.
Note that unlike other programming languages, else_branch is required argument, not
optional.
This function is used in the implementation of "IF" control operator in XQUERY, so you will probably use that operator in XQUERY expressions, not the function. This function may be useful in XPATH expressions and in XSLT stylesheets. It is not a part of library of standard XQUERY 1.0 functions.
Parameters
test
Boolean value used to choose an expression to execute
then_branch
Expression which is calculated if test argument is true
else_branch
Expression which is calculated if test argument is false
Return Types
Any
Examples
Example24.593.
These two expressions are equivalent, but first may be used in any XPATH while second is written in XQUERY syntax:
if (2 * 2 = 4, 'I think so', 'Unbelievable!') IF 2 * 2 = 4 THEN 'I think so' ELSE 'Unbelievable!'