struct::set(n)							Tcl Data Structures						    struct::set(n)

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NAME

       struct::set - Procedures for manipulating sets

SYNOPSIS

       package require Tcl  8.0

       package require struct::set  ?2.2.3?

       ::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

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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

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

       ::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.

       ::struct::set contains set item
	      Returns a boolean value indicating if the set contains the element item (true), or not (false).

       ::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 com-
	      mand.

       ::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  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.

       ::struct::set equal set1 set2
	      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
	      near-equivalent of lreplace for sets.

       ::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.

       ::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.

       ::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).

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 SF Trackers [http://sourceforge.net/tracker/?group_id=12883].  Please also report any ideas for enhancements  you  may
       have for either package and/or documentation.

KEYWORDS

       cardinality, difference, emptiness, exclusion, inclusion, intersection, membership, set, symmetric difference, union

COPYRIGHT

       Copyright (c) 2004-2008 Andreas Kupries <andreas_kupries@users.sourceforge.net>

struct								       2.2.3							    struct::set(n)