Name
for — Repeats some calculation for every item of a given sequence
Synopsis
any
for
(
|
varname string , |
| source_set sequence , | |
mapping_expn
any
); |
Description
The function creates a temporary local variable, whose name is specified by
varname
argument.
Then, for every item of source_set
sequence it
calculates the value of mapping_expn
expression
having set the created variable to that "current" item.
It returns the "flattened" sequence of values returned by
mapping_expn
in the same order as they are calculated.
"Flattened" means that if mapping_expn
returns an sequence, items of this sequence will be added into the end of
resulting sequence, one by one, instead of adding one item of type "sequence".
The temporary variable is destroyed on return.
This function is used in the implementation of "FOR" 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
varname
Name of temporary variable
source_set
Sequence of items; every item will cause one call of
mapping_expn
mapping_expn
An expression which should be calculated for items of
source_set
.
Return Types
Sequence
Examples
Example 24.588.
These two expressions are equivalent, but first may be used in any XPATH while second is written in XQUERY syntax
for('itm', /bid/item, 0.20 * $itm/price)
FOR $itm IN /bid/item RETURN 0.20 * $bid_item/price