[//000000001]: # (struct::set \- Tcl Data Structures)
[//000000002]: # (Generated from file 'struct\_set\.man' by tcllib/doctools with format 'markdown')
[//000000003]: # (Copyright © 2004\-2008 Andreas Kupries <andreas\_kupries@users\.sourceforge\.net>)
[//000000004]: # (struct::set\(n\) 2\.2\.3 tcllib "Tcl Data Structures")
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# NAME
struct::set \- Procedures for manipulating sets
# <a name='toc'></a>Table Of Contents
- [Table Of Contents](#toc)
- [Synopsis](#synopsis)
- [Description](#section1)
- [COMMANDS](#section2)
- [REFERENCES](#section3)
- [Bugs, Ideas, Feedback](#section4)
- [Keywords](#keywords)
- [Category](#category)
- [Copyright](#copyright)
# <a name='synopsis'></a>SYNOPSIS
package require Tcl 8\.0
package require struct::set ?2\.2\.3?
[__::struct::set__ __empty__ *set*](#1)
[__::struct::set__ __size__ *set*](#2)
[__::struct::set__ __contains__ *set* *item*](#3)
[__::struct::set__ __union__ ?*set1*\.\.\.?](#4)
[__::struct::set__ __intersect__ ?*set1*\.\.\.?](#5)
[__::struct::set__ __difference__ *set1* *set2*](#6)
[__::struct::set__ __symdiff__ *set1* *set2*](#7)
[__::struct::set__ __intersect3__ *set1* *set2*](#8)
[__::struct::set__ __equal__ *set1* *set2*](#9)
[__::struct::set__ __include__ *svar* *item*](#10)
[__::struct::set__ __exclude__ *svar* *item*](#11)
[__::struct::set__ __add__ *svar* *set*](#12)
[__::struct::set__ __subtract__ *svar* *set*](#13)
[__::struct::set__ __subsetof__ *A* *B*](#14)
# <a name='description'></a>DESCRIPTION
The __::struct::set__ namespace contains several useful commands for
processing finite sets\.
It exports only a single command, __struct::set__\. All functionality
provided here can be reached through a subcommand of this command\.
*Note:* As of version 2\.2 of this package a critcl based C implementation is
available\. This implementation however requires Tcl 8\.4 to run\.
# <a name='section2'></a>COMMANDS
- <a name='1'></a>__::struct::set__ __empty__ *set*
Returns a boolean value indicating if the *set* is empty \(__true__\),
or not \(__false__\)\.
- <a name='2'></a>__::struct::set__ __size__ *set*
Returns an integer number greater than or equal to zero\. This is the number
of elements in the *set*\. In other words, its cardinality\.
- <a name='3'></a>__::struct::set__ __contains__ *set* *item*
Returns a boolean value indicating if the *set* contains the element
*item* \(__true__\), or not \(__false__\)\.
- <a name='4'></a>__::struct::set__ __union__ ?*set1*\.\.\.?
Computes the set containing the union of *set1*, *set2*, etc\., i\.e\.
"*set1* \+ *set2* \+ \.\.\.", and returns this set as the result of the
command\.
- <a name='5'></a>__::struct::set__ __intersect__ ?*set1*\.\.\.?
Computes the set containing the intersection of *set1*, *set2*, etc\.,
i\.e\. "*set1* \* *set2* \* \.\.\.", and returns this set as the result of the
command\.
- <a name='6'></a>__::struct::set__ __difference__ *set1* *set2*
Computes the set containing the difference of *set1* and *set2*, i\.e\.
\("*set1* \- *set2*"\) and returns this set as the result of the command\.
- <a name='7'></a>__::struct::set__ __symdiff__ *set1* *set2*
Computes the set containing the symmetric difference of *set1* and
*set2*, i\.e\. \("\(*set1* \- *set2*\) \+ \(*set2* \- *set1*\)"\) and returns
this set as the result of the command\.
- <a name='8'></a>__::struct::set__ __intersect3__ *set1* *set2*
This command is a combination of the methods __intersect__ and
__difference__\. It returns a three\-element list containing
"*set1*\**set2*", "*set1*\-*set2*", and "*set2*\-*set1*", in this
order\. In other words, the intersection of the two parameter sets, and their
differences\.
- <a name='9'></a>__::struct::set__ __equal__ *set1* *set2*
Returns a boolean value indicating if the two sets are equal \(__true__\)
or not \(__false__\)\.
- <a name='10'></a>__::struct::set__ __include__ *svar* *item*
The element *item* is added to the set specified by the variable name in
*svar*\. The return value of the command is empty\. This is the equivalent
of __lappend__ for sets\. If the variable named by *svar* does not
exist it will be created\.
- <a name='11'></a>__::struct::set__ __exclude__ *svar* *item*
The element *item* is removed from the set specified by the variable name
in *svar*\. The return value of the command is empty\. This is a
near\-equivalent of __lreplace__ for sets\.
- <a name='12'></a>__::struct::set__ __add__ *svar* *set*
All the element of *set* are added to the set specified by the variable
name in *svar*\. The return value of the command is empty\. This is like the
method __include__, but for the addition of a whole set\. If the variable
named by *svar* does not exist it will be created\.
- <a name='13'></a>__::struct::set__ __subtract__ *svar* *set*
All the element of *set* are removed from the set specified by the
variable name in *svar*\. The return value of the command is empty\. This is
like the method __exclude__, but for the removal of a whole set\.
- <a name='14'></a>__::struct::set__ __subsetof__ *A* *B*
Returns a boolean value indicating if the set *A* is a true subset of or
equal to the set *B* \(__true__\), or not \(__false__\)\.
# <a name='section3'></a>REFERENCES
# <a name='section4'></a>Bugs, Ideas, Feedback
This document, and the package it describes, will undoubtedly contain bugs and
other problems\. Please report such in the category *struct :: set* of the
[Tcllib Trackers](http://core\.tcl\.tk/tcllib/reportlist)\. Please also report
any ideas for enhancements you may have for either package and/or documentation\.
When proposing code changes, please provide *unified diffs*, i\.e the output of
__diff \-u__\.
Note further that *attachments* are strongly preferred over inlined patches\.
Attachments can be made by going to the __Edit__ form of the ticket
immediately after its creation, and then using the left\-most button in the
secondary navigation bar\.
# <a name='keywords'></a>KEYWORDS
[cardinality](\.\./\.\./\.\./\.\./index\.md\#cardinality),
[difference](\.\./\.\./\.\./\.\./index\.md\#difference),
[emptiness](\.\./\.\./\.\./\.\./index\.md\#emptiness),
[exclusion](\.\./\.\./\.\./\.\./index\.md\#exclusion),
[inclusion](\.\./\.\./\.\./\.\./index\.md\#inclusion),
[intersection](\.\./\.\./\.\./\.\./index\.md\#intersection),
[membership](\.\./\.\./\.\./\.\./index\.md\#membership),
[set](\.\./\.\./\.\./\.\./index\.md\#set), [symmetric
difference](\.\./\.\./\.\./\.\./index\.md\#symmetric\_difference),
[union](\.\./\.\./\.\./\.\./index\.md\#union)
# <a name='category'></a>CATEGORY
Data structures
# <a name='copyright'></a>COPYRIGHT
Copyright © 2004\-2008 Andreas Kupries <andreas\_kupries@users\.sourceforge\.net>
