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NAME
struct::set  Procedures for manipulating sets
Table Of Contents
SYNOPSIS
package require Tcl 8.5 9
package require struct::set ?2.2.4?
::struct::set empty set
::struct::set size set
::struct::set contains set item
::struct::set union ?set1...?
::struct::set intersect ?set1...?
::struct::set difference set1 set2
::struct::set symdiff set1 set2
::struct::set intersect3 set1 set2
::struct::set equal set1 set2
::struct::set include svar item
::struct::set exclude svar item
::struct::set add svar set
::struct::set subtract svar set
::struct::set subsetof A B
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.
COMMANDS

Returns a boolean value indicating if the set is empty (true), or not (false).

Returns an integer number greater than or equal to zero. This is the number of elements in the set. In other words, its cardinality.
::struct::set contains set item
Returns a boolean value indicating if the set contains the element item (true), or not (false).

Computes the set containing the union of set1, set2, etc., i.e. "set1 + set2 + ...", and returns this set as the result of the command.
::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.
::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.
::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.
::struct::set intersect3 set1 set2
This command is a combination of the methods intersect and difference. It returns a threeelement list containing "set1*set2", "set1set2", and "set2set1", in this order. In other words, the intersection of the two parameter sets, and their differences.

Returns a boolean value indicating if the two sets are equal (true) or not (false).
::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.
::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 nearequivalent of lreplace for sets.

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.
::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.

Returns a boolean value indicating if the set A is a true subset of or equal to the set B (true), or not (false).
REFERENCES
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. 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 leftmost button in the secondary navigation bar.
KEYWORDS
cardinality, difference, emptiness, exclusion, inclusion, intersection, membership, set, symmetric difference, union
CATEGORY
Data structures
COPYRIGHT
Copyright © 20042008 Andreas Kupries