[manpage_begin struct::prioqueue n 1.4]
[moddesc   {Tcl Data Structures}]
[copyright {2003 Michael Schlenker <mic42@users.sourceforge.net>}]
[titledesc {Create and manipulate prioqueue objects}]
[category  {Data structures}]
[require Tcl 8.2]
[require struct::prioqueue [opt 1.4]]
[description]

This package implements a simple priority queue using nested tcl lists.

[para]

The command [cmd ::struct::prioqueue] creates a new priority queue
with default priority key type [arg -integer]. This means that keys
given to the [method put] subcommand must have this type.

[para]

This also sets the priority ordering. For key types [arg -ascii] and
[arg -dictionary] the data is sorted in ascending order (as with
[cmd lsort] [arg -increasing]), thereas for [arg -integer] and
[arg -real] the data is sorted in descending order (as with
[cmd lsort] [arg -decreasing]).

[para]

Prioqueue names are unrestricted, but may be recognized as options if
no priority type is given.


[list_begin definitions]

[call [cmd ::struct::prioqueue] [opt [option {-ascii|-dictionary|-integer|-real}]] [opt [arg prioqueueName]] ]

The [cmd ::struct::prioqueue] command creates a new prioqueue object
with an associated global Tcl command whose name is

[emph prioqueueName]. This command may be used to invoke various
operations on the prioqueue.  It has the following general form:


[call [arg prioqueueName] [cmd option] [opt [arg {arg arg ...}]]]

[cmd option] and the [arg arg]s determine the exact behavior of the
command.  The following commands are possible for prioqueue objects:


[call [arg prioqueueName] [cmd clear]]

Remove all items from the prioqueue.


[call [arg prioqueueName] [cmd remove] [arg item]]

Remove the selected item from this priority queue.


[call [arg prioqueueName] [cmd destroy]]

Destroy the prioqueue, including its storage space and associated
command.


[call [arg prioqueueName] [cmd get] [opt [arg count]]]

Return the front [arg count] items of the prioqueue (but not their
priorities) and remove them from the prioqueue. 

If [arg count] is not specified, it defaults to 1.  If [arg count] is
1, the result is a simple string; otherwise, it is a list.  If
specified, [arg count] must be greater than or equal to 1.  If there
are no or too few items in the prioqueue, this command will throw an
error.


[call [arg prioqueueName] [cmd peek] [opt [arg count]]]

Return the front [arg count] items of the prioqueue (but not their
priorities), without removing them from the prioqueue.

If [arg count] is not specified, it defaults to 1.  If [arg count] is
1, the result is a simple string; otherwise, it is a list.  If
specified, [arg count] must be greater than or equal to 1.  If there
are no or too few items in the queue, this command will throw an
error.

[call [arg prioqueueName] [cmd peekpriority] [opt [arg count]]]

Return the front [arg count] items priority keys, without removing
them from the prioqueue.

If [arg count] is not specified, it defaults to 1.  If [arg count] is
1, the result is a simple string; otherwise, it is a list.  If
specified, [arg count] must be greater than or equal to 1.  If there
are no or too few items in the queue, this command will throw an
error.

[call [arg prioqueueName] [cmd put] [arg {item prio}] [opt [arg {item prio ...}]]]

Put the [arg item] or items specified into the prioqueue. [arg prio]
must be a valid priority key for this type of prioqueue, otherwise an
error is thrown and no item is added.  Items are inserted at their
priority ranking. Items with equal priority are added in the order
they were added.


[call [arg prioqueueName] [cmd size]]

Return the number of items in the prioqueue.


[list_end]


[section {BUGS, IDEAS, FEEDBACK}]

This document, and the package it describes, will undoubtedly contain
bugs and other problems.

Please report such in the category [emph {struct :: prioqueue}] of the
[uri {http://sourceforge.net/tracker/?group_id=12883} {Tcllib SF Trackers}].

Please also report any ideas for enhancements you may have for either
package and/or documentation.


[keywords {ordered list} prioqueue {priority queue}]
[manpage_end]