http://zorba.io/modules/stack

Description

Before using any of the functions below please remember to import the module namespace:

import module namespace stack = "http://zorba.io/modules/stack";

Implementation of stack for items, using dynamic collections.

Entries in the stack must be structured items - that is, either JSON Objects or Arrays, or XML Nodes.

Module code

Here is the actual XQuery module code.

Imported modules

Authors

Daniel Turcanu, Sorin Nasoi

Version Declaration

xquery version "3.0" encoding "utf-8";

Namespaces

ann	http://zorba.io/annotations
collections-ddl	http://zorba.io/modules/store/dynamic/collections/ddl
collections-dml	http://zorba.io/modules/store/dynamic/collections/dml
stack	http://zorba.io/modules/stack
ver	http://zorba.io/options/versioning

Variables

stack:errNS
stack:NOT-EXISTS
stack:EXISTS

Function Summary

create($name as xs:QName) as empty-sequence() Create a stack with this name.
top($name as xs:QName) as structured-item()? Return the top item in the stack, without removing it.
pop($name as xs:QName) as structured-item()? Return the top item in the stack, and remove it.
push($name as xs:QName, $value as structured-item()) as empty-sequence() Add a new item to the stack; the stack will contain a copy of the given item.
empty($name as xs:QName) as xs:boolean Checks if a stack exists and is empty.
size($name as xs:QName) as xs:integer Count of items in the stack.
copy($destName as xs:QName, $sourceName as xs:QName) as empty-sequence() Copy all items from source stack to a destination stack.

Functions

create#1

declare %ann:sequential function stack:create(
    $name as xs:QName
) as empty-sequence()

Create a stack with this name. If stack exists, an error is raised.

Parameters

$name
name of the new stack.

Returns

empty-sequence()
an empty sequence.

Errors

stack:EXISTS
if the stack identified by $name already exists.

top#1

declare function stack:top(
    $name as xs:QName
) as structured-item()?

Return the top item in the stack, without removing it.

Parameters

$name
name of the stack.

Returns

structured-item()?
the top item, or empty sequence if stack is empty.

Errors

stack:NOT-EXISTS
if the stack identified by $name does not exist.

Examples

top1.xq

pop#1

declare %ann:sequential function stack:pop(
    $name as xs:QName
) as structured-item()?

Return the top item in the stack, and remove it.

Parameters

$name
name of the stack.

Returns

structured-item()?
the top item, or empty sequence if stack is empty.

Errors

stack:NOT-EXISTS
if the stack identified by $name does not exist.

Examples

pop2.xq

push#2

declare %ann:sequential function stack:push(
    $name as xs:QName,
    $value as structured-item()
) as empty-sequence()

Add a new item to the stack; the stack will contain a copy of the given item.

Parameters

$name
name of the stack.
$value
the item to be added.

Returns

empty-sequence()
an empty sequence.

Errors

stack:NOT-EXISTS
if the stack identified by $name does not exist.

Examples

push1.xq

empty#1

declare function stack:empty(
    $name as xs:QName
) as xs:boolean

Checks if a stack exists and is empty.

Parameters

$name
name of the stack.

Returns

xs:boolean
true if the stack is empty or does not exist.

Errors

stack:NOT-EXISTS
if the stack identified by $name does not exist.

Examples

empty1.xq

size#1

declare function stack:size(
    $name as xs:QName
) as xs:integer

Count of items in the stack.

Parameters

$name
name of the stack.

Returns

xs:integer
the amount of items.

Errors

stack:NOT-EXISTS
if the stack identified by $name does not exist.

Examples

size1.xq

copy#2

declare %ann:sequential function stack:copy(
    $destName as xs:QName,
    $sourceName as xs:QName
) as empty-sequence()

Copy all items from source stack to a destination stack.

If destination stack does not exist, it is created first.

If destination stack is not empty, the items are appended on top.

Parameters

$destName
name of the destination stack.
$sourceName
name of the source stack.

Returns

empty-sequence()
an empty sequence.

Examples

copy1.xq