[catagits/Catalyst-Manual.git] / lib / Catalyst / Manual / Tutorial / Intro.pod

=head1 NAME

Catalyst::Manual::Tutorial::Intro - Catalyst Tutorial - Part 1: Introduction


=head1 OVERVIEW

This is B<Part 1 of 10> for the Catalyst tutorial.

L<Tutorial Overview|Catalyst::Manual::Tutorial>

=over 4

=item 1

B<Introduction>

=item 2

L<Catalyst Basics|Catalyst::Manual::Tutorial::CatalystBasics>

=item 3

L<More Catalyst Basics|Catalyst::Manual::Tutorial::MoreCatalystBasics>

=item 4

L<Basic CRUD|Catalyst::Manual::Tutorial::BasicCRUD>

=item 5

L<Authentication|Catalyst::Manual::Tutorial::Authentication>

=item 6

L<Authorization|Catalyst::Manual::Tutorial::Authorization>

=item 7

L<Debugging|Catalyst::Manual::Tutorial::Debugging>

=item 8

L<Testing|Catalyst::Manual::Tutorial::Testing>

=item 9

L<Advanced CRUD|Catalyst::Manual::Tutorial::AdvancedCRUD>

=item 10

L<Appendices|Catalyst::Manual::Tutorial::Appendices>

=back


=head1 DESCRIPTION

This tutorial provides a multipart introduction to the Catalyst web
framework. It seeks to provide a rapid overview of many of its most
commonly used features. The focus is on the real-world best practices
required in the construction of nearly all Catalyst applications.

Although the primary target of the tutorial is users new to the Catalyst
framework, experienced users may wish to review specific sections (for
example, how to use DBIC for their model classes, how to add
authentication and authorization to an existing application, or form
management).

You can obtain the code for all the tutorial examples from the
catalyst subversion repository by issuing the command:

    svn co http://dev.catalyst.perl.org/repos/Catalyst/tags/examples/Tutorial/MyApp/5.7/ CatalystTutorial

This will download the current code for each tutorial chapter in the
CatalystTutorial directory.  Each example application directory has
the same name as the tutorial chapter.

B<These reference implementations are provided so that when you follow
the tutorial, you can use the code from the subversion repository to
ensure that your system is set up correctly, and that you have not
inadvertently made any typographic errors, or accidentally skipped
part of the tutorial.>

Additionally, if you're reading this manual online, you can download
the example program and all the necessary dependencies to
your local machine by installing the C<Task::Catalyst::Tutorial>
distribution from CPAN:

     cpan Task::Catalyst::Tutorial

This will also test to make sure the dependencies are working.  If you
have trouble installing these, please ask for help on the #catalyst
IRC channel, or the Catalyst mailing list.

Subjects covered include:

=over 4

=item * 

A simple application that lists and adds books.

=item *

The use of L<DBIx::Class|DBIx::Class> (DBIC) for the model.

=item * 

How to write CRUD (Create, Read, Update, and Delete) operations in
Catalyst.

=item *

Authentication ("auth").

=item * 

Role-based authorization ("authz").

=item * 

Attempts to provide an example showing current (5.7XXX) Catalyst
practices. For example, the use of 
L<Catalyst::Action::RenderView|Catalyst::Action::RenderView>,
DBIC, L<Catalyst::Plugin::ConfigLoader|Catalyst::Plugin::ConfigLoader> 
with C<myapp.yml>, the use of C<lib/MyApp/Controller/Root.pm> 
vs. C<lib/MyApp.pm>, etc.

=item * 

The use of Template Toolkit (TT) and the
L<Catalyst::Helper::View::TTSite|Catalyst::Helper::View::TTSite> 
view helper.

=item * 

Useful techniques for troubleshooting and debugging Catalyst
applications.

=item * 

The use of SQLite as a database (with code also provided for MySQL and
PostgreSQL).

=item * 

The use of L<HTML::FormFu|HTML::FormFu> for automated form processing 
and validation.

=back

This tutorial makes the learning process its main priority.  For
example, the level of comments in the code found here would likely be
considered excessive in a "normal project."  Because of their contextual
value, this tutorial will generally favor inline comments over a
separate discussion in the text.  It also deliberately tries to
demonstrate multiple approaches to various features (in general, you
should try to be as consistent as possible with your own production
code).

Furthermore, this tutorial tries to minimize the number of controllers,
models, TT templates, and database tables.  Although this does result in
things being a bit contrived at times, the concepts should be applicable
to more complex environments.  More complete and complicated example
applications can be found in the C<examples> area of the Catalyst
Subversion repository at
L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/>.

B<Note:> There are a variety of other introductory materials available
through the Catalyst web site and at
L<http://dev.catalyst.perl.org/wiki/UserIntroductions> and
L<http://dev.catalyst.perl.org/>.

=head1 VERSIONS AND CONVENTIONS USED IN THIS TUTORIAL

This tutorial was built using the following resources. Please note that
you may need to make adjustments for different environments and
versions:

=over 4

=item * 

Ubuntu 8.04 Hardy Heron

=item * 

Catalyst v5.7011

=item *

Catalyst::Devel v1.03

=item * 

DBIx::Class v0.08008

=item * 

Catalyst Plugins

The plugins used in this tutorial all have sufficiently stable APIs that
you shouldn't need to worry about versions. However, there could be
cases where the tutorial is affected by what version of plugins you
use. This tutorial has been tested against the following set of plugins:

=over 4

=item * 

Catalyst::Plugin::Authentication -- v0.10002

=item *

Catalyst::Plugin::Authentication::Store::DBIC -- v0.09

=item *

Catalyst::Plugin::Authorization::ACL -- v0.08

=item *

Catalyst::Plugin::Authorization::Roles -- v0.05

=item *

Catalyst::Plugin::ConfigLoader -- v0.17

=item *

Catalyst::Plugin::Session -- v0.18

=item *

Catalyst::Plugin::Session::State::Cookie -- v0.08

=item *

Catalyst::Plugin::Session::Store::FastMmap -- v0.03

=item *

Catalyst::Plugin::StackTrace -- v0.06

=item *

Catalyst::Plugin::Static::Simple -- v0.20

=back

=item * 

Since the web browser is being used on the same box where Perl and the
Catalyst development server is running, the URL of
C<http://localhost:3000> will be used (the Catalyst development server
defaults to port 3000).  If you are running Perl on a different box than
where your web browser is located (or using a different port number via
the C<-p> I<port_number> option to the development server), then you
will need to update the URL you use accordingly.

=item * 

Depending on the web browser you are using, you might need to hit
C<Shift+Reload> to pull a fresh page when testing your application at
various points.  Also, the C<-k> keepalive option to the development
server can be necessary with some browsers (especially Internet
Explorer).

=back

=head1 CATALYST INSTALLATION

If approach in the wrong manner, it can be a daunting tasks to get
Catalyst initally installed.  Although a compelling strength of
Catalyst is that it makes use of many of the modules in the
vast repository that is CPAN, this can complicate the installation
process.  However, there are a growing number of methods 
that can dramatically ease this undertaking.  Of these, the following 
are likely to be applicable to the largest number of potential new 
users:

=over 4

=item *

Ubuntu

Given the popularity of Ubuntu and it's ease of use, Ubuntu can be 
a great way for newcomers to experiment with Catalyst.  Because it 
is a "live CD," you can simply boot from the CD, run a few commands,
and you should have a fully functional environment in which to do 
this tutorial in a matter of minutes.  

=over 4

=item * 

Download Ubuntu 8.04 (aka, Hardy Heron) and boot from the CD and/or
image file, select your language, and then "Try Ubuntu without any
changes to your computer."

=item *

Open a terminal session.

=item *

Add the 'universe' repositories:

    sudo vi /etc/apt/sources.list

And remove the comments from the lines under the comments about the
'universe' repositories.

=item *

Install Catalyst:

    sudo apt-get update
    sudo apt-get upgrade
    sudo apt-get install sqlite3 libdbd-sqlite3-perl libcatalyst-perl libcatalyst-modules-perl

Accept all of the dependencies.  Done.

=back

=item * 

Matt Trout's C<cat-install>

Available at L<http://www.shadowcatsystems.co.uk/static/cat-install>,
C<cat-install> can be a quick and painless way to get Catalyst up and
running.  Just download the script from the link above and type C<perl
cat-install>.

=item * 

Chris Laco's CatInABox

Download the tarball from
L<http://handelframework.com/downloads/CatInABox.tar.gz> and unpack it
on your machine.  Depending on your OS platform, either run C<start.bat>
or C<start.sh>.

=item * 

Pre-Built VMWare Images

Under the VMWare community program, work is ongoing to develop a number
of VMWare images where an entire Catalyst development environment has
already been installed, complete with database engines and a full
complement of Catalyst plugins.

=back

For additional information and recommendations on Catalyst installation,
please refer to 
L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>.

B<NOTE:> Step-by-step instructions to replicate the environment on
which this tutorial was developed can be found at
L<Catalyst::Manual::Installation::CentOS4|Catalyst::Manual::Installation::CentOS4>. 
Using these instructions, you should be able to build a complete CentOS
4.X server with Catalyst and all the plugins required to run this
tutorial.

=head1 DATABASES

This tutorial will primarily focus on SQLite because of its simplicity
of installation and use; however, modifications in the script required
to support MySQL and PostgreSQL will be presented in Appendix 2.

B<Note:> One of the advantages of the MVC design patterns is that
applications become much more database independent.  As such, you will
notice that only the C<.sql> files used to initialize the database
change between database systems: the Catalyst code generally remains the
same.

=head1 WHERE TO GET WORKING CODE

Each part of the tutorial has complete code available in the main
Catalyst Subversion repository (see the note at the beginning of each
part for the appropriate svn command to use).  Additionally, the final
code is available as a ready-to-run tarball at
L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/Tutorial/Final_Tarball/MyApp.tgz>.

B<NOTE:> You can run the test cases for the final code with the following 
commands:

    wget http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/Tutorial/Final_Tarball/MyApp.tgz
    tar zxvf MyApp.tgz
    cd MyApp
    CATALYST_DEBUG=0 prove --lib lib  t


=head1 AUTHOR

Kennedy Clark, C<hkclark@gmail.com>

Please report any errors, issues or suggestions to the author.  The
most recent version of the Catalyst Tutorial can be found at
L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/Catalyst-Manual/lib/Catalyst/Manual/Tutorial/>.

Copyright 2006, Kennedy Clark, under Creative Commons License
(L<http://creativecommons.org/licenses/by-nc-sa/2.5/>).
Commit	Line	Data
d442cc9f	1	=head1 NAME
	2
	3	Catalyst::Manual::Tutorial::Intro - Catalyst Tutorial - Part 1: Introduction
	4
	5
	6	=head1 OVERVIEW
	7
50211f3c	8	This is B<Part 1 of 10> for the Catalyst tutorial.
d442cc9f	9
	10	L<Tutorial Overview\|Catalyst::Manual::Tutorial>
	11
	12	=over 4
	13
	14	=item 1
	15
	16	B<Introduction>
	17
	18	=item 2
	19
	20	L<Catalyst Basics\|Catalyst::Manual::Tutorial::CatalystBasics>
	21
	22	=item 3
	23
1def4a20	24	L<More Catalyst Basics\|Catalyst::Manual::Tutorial::MoreCatalystBasics>
d442cc9f	25
	26	=item 4
	27
1def4a20	28	L<Basic CRUD\|Catalyst::Manual::Tutorial::BasicCRUD>
d442cc9f	29
	30	=item 5
	31
1def4a20	32	L<Authentication\|Catalyst::Manual::Tutorial::Authentication>
d442cc9f	33
	34	=item 6
	35
1def4a20	36	L<Authorization\|Catalyst::Manual::Tutorial::Authorization>
d442cc9f	37
	38	=item 7
	39
1def4a20	40	L<Debugging\|Catalyst::Manual::Tutorial::Debugging>
d442cc9f	41
	42	=item 8
	43
1def4a20	44	L<Testing\|Catalyst::Manual::Tutorial::Testing>
d442cc9f	45
	46	=item 9
	47
1def4a20	48	L<Advanced CRUD\|Catalyst::Manual::Tutorial::AdvancedCRUD>
	49
	50	=item 10
	51
d442cc9f	52	L<Appendices\|Catalyst::Manual::Tutorial::Appendices>
	53
	54	=back
	55
1def4a20	56
d442cc9f	57	=head1 DESCRIPTION
	58
	59	This tutorial provides a multipart introduction to the Catalyst web
	60	framework. It seeks to provide a rapid overview of many of its most
	61	commonly used features. The focus is on the real-world best practices
	62	required in the construction of nearly all Catalyst applications.
	63
	64	Although the primary target of the tutorial is users new to the Catalyst
	65	framework, experienced users may wish to review specific sections (for
1def4a20	66	example, how to use DBIC for their model classes, how to add
	67	authentication and authorization to an existing application, or form
	68	management).
d442cc9f	69
	70	You can obtain the code for all the tutorial examples from the
	71	catalyst subversion repository by issuing the command:
	72
	73	svn co http://dev.catalyst.perl.org/repos/Catalyst/tags/examples/Tutorial/MyApp/5.7/ CatalystTutorial
	74
	75	This will download the current code for each tutorial chapter in the
	76	CatalystTutorial directory. Each example application directory has
	77	the same name as the tutorial chapter.
	78
3d9ae335	79	B<These reference implementations are provided so that when you follow
	80	the tutorial, you can use the code from the subversion repository to
	81	ensure that your system is set up correctly, and that you have not
	82	inadvertently made any typographic errors, or accidentally skipped
	83	part of the tutorial.>
	84
d442cc9f	85	Additionally, if you're reading this manual online, you can download
3dcf2e2c	86	the example program and all the necessary dependencies to
d442cc9f	87	your local machine by installing the C<Task::Catalyst::Tutorial>
	88	distribution from CPAN:
	89
	90	cpan Task::Catalyst::Tutorial
	91
	92	This will also test to make sure the dependencies are working. If you
	93	have trouble installing these, please ask for help on the #catalyst
	94	IRC channel, or the Catalyst mailing list.
	95
	96	Subjects covered include:
	97
	98	=over 4
	99
	100	=item *
	101
	102	A simple application that lists and adds books.
	103
	104	=item *
	105
	106	The use of L<DBIx::Class\|DBIx::Class> (DBIC) for the model.
	107
	108	=item *
	109
	110	How to write CRUD (Create, Read, Update, and Delete) operations in
	111	Catalyst.
	112
	113	=item *
	114
	115	Authentication ("auth").
	116
	117	=item *
	118
	119	Role-based authorization ("authz").
	120
	121	=item *
	122
	123	Attempts to provide an example showing current (5.7XXX) Catalyst
	124	practices. For example, the use of
	125	L<Catalyst::Action::RenderView\|Catalyst::Action::RenderView>,
	126	DBIC, L<Catalyst::Plugin::ConfigLoader\|Catalyst::Plugin::ConfigLoader>
	127	with C<myapp.yml>, the use of C<lib/MyApp/Controller/Root.pm>
	128	vs. C<lib/MyApp.pm>, etc.
	129
	130	=item *
	131
	132	The use of Template Toolkit (TT) and the
	133	L<Catalyst::Helper::View::TTSite\|Catalyst::Helper::View::TTSite>
	134	view helper.
	135
	136	=item *
	137
	138	Useful techniques for troubleshooting and debugging Catalyst
	139	applications.
	140
	141	=item *
	142
	143	The use of SQLite as a database (with code also provided for MySQL and
	144	PostgreSQL).
	145
	146	=item *
	147
1def4a20	148	The use of L<HTML::FormFu\|HTML::FormFu> for automated form processing
d442cc9f	149	and validation.
	150
	151	=back
	152
	153	This tutorial makes the learning process its main priority. For
	154	example, the level of comments in the code found here would likely be
1def4a20	155	considered excessive in a "normal project." Because of their contextual
d442cc9f	156	value, this tutorial will generally favor inline comments over a
	157	separate discussion in the text. It also deliberately tries to
	158	demonstrate multiple approaches to various features (in general, you
	159	should try to be as consistent as possible with your own production
	160	code).
	161
	162	Furthermore, this tutorial tries to minimize the number of controllers,
	163	models, TT templates, and database tables. Although this does result in
	164	things being a bit contrived at times, the concepts should be applicable
	165	to more complex environments. More complete and complicated example
	166	applications can be found in the C<examples> area of the Catalyst
	167	Subversion repository at
	168	L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/>.
	169
	170	B<Note:> There are a variety of other introductory materials available
	171	through the Catalyst web site and at
	172	L<http://dev.catalyst.perl.org/wiki/UserIntroductions> and
	173	L<http://dev.catalyst.perl.org/>.
	174
	175	=head1 VERSIONS AND CONVENTIONS USED IN THIS TUTORIAL
	176
	177	This tutorial was built using the following resources. Please note that
	178	you may need to make adjustments for different environments and
	179	versions:
	180
	181	=over 4
	182
	183	=item *
	184
1def4a20	185	Ubuntu 8.04 Hardy Heron
d442cc9f	186
	187	=item *
	188
1def4a20	189	Catalyst v5.7011
dd88c3b6	190
22a67212	191	=item *
dd88c3b6	192
1def4a20	193	Catalyst::Devel v1.03
d442cc9f	194
	195	=item *
	196
1def4a20	197	DBIx::Class v0.08008
d442cc9f	198
	199	=item *
	200
	201	Catalyst Plugins
	202
	203	The plugins used in this tutorial all have sufficiently stable APIs that
	204	you shouldn't need to worry about versions. However, there could be
	205	cases where the tutorial is affected by what version of plugins you
	206	use. This tutorial has been tested against the following set of plugins:
	207
	208	=over 4
	209
	210	=item *
	211
1def4a20	212	Catalyst::Plugin::Authentication -- v0.10002
d442cc9f	213
	214	=item *
	215
1def4a20	216	Catalyst::Plugin::Authentication::Store::DBIC -- v0.09
d442cc9f	217
	218	=item *
	219
1def4a20	220	Catalyst::Plugin::Authorization::ACL -- v0.08
d442cc9f	221
	222	=item *
	223
1def4a20	224	Catalyst::Plugin::Authorization::Roles -- v0.05
d442cc9f	225
	226	=item *
	227
1def4a20	228	Catalyst::Plugin::ConfigLoader -- v0.17
d442cc9f	229
	230	=item *
	231
1def4a20	232	Catalyst::Plugin::Session -- v0.18
d442cc9f	233
	234	=item *
	235
1def4a20	236	Catalyst::Plugin::Session::State::Cookie -- v0.08
d442cc9f	237
	238	=item *
	239
1def4a20	240	Catalyst::Plugin::Session::Store::FastMmap -- v0.03
d442cc9f	241
	242	=item *
	243
1def4a20	244	Catalyst::Plugin::StackTrace -- v0.06
d442cc9f	245
	246	=item *
	247
1def4a20	248	Catalyst::Plugin::Static::Simple -- v0.20
d442cc9f	249
	250	=back
	251
	252	=item *
	253
	254	Since the web browser is being used on the same box where Perl and the
	255	Catalyst development server is running, the URL of
	256	C<http://localhost:3000> will be used (the Catalyst development server
	257	defaults to port 3000). If you are running Perl on a different box than
	258	where your web browser is located (or using a different port number via
	259	the C<-p> I<port_number> option to the development server), then you
	260	will need to update the URL you use accordingly.
	261
	262	=item *
	263
	264	Depending on the web browser you are using, you might need to hit
	265	C<Shift+Reload> to pull a fresh page when testing your application at
	266	various points. Also, the C<-k> keepalive option to the development
	267	server can be necessary with some browsers (especially Internet
	268	Explorer).
	269
	270	=back
	271
	272	=head1 CATALYST INSTALLATION
	273
1def4a20	274	If approach in the wrong manner, it can be a daunting tasks to get
	275	Catalyst initally installed. Although a compelling strength of
	276	Catalyst is that it makes use of many of the modules in the
	277	vast repository that is CPAN, this can complicate the installation
	278	process. However, there are a growing number of methods
	279	that can dramatically ease this undertaking. Of these, the following
	280	are likely to be applicable to the largest number of potential new
	281	users:
	282
	283	=over 4
	284
	285	=item *
	286
	287	Ubuntu
	288
	289	Given the popularity of Ubuntu and it's ease of use, Ubuntu can be
	290	a great way for newcomers to experiment with Catalyst. Because it
	291	is a "live CD," you can simply boot from the CD, run a few commands,
	292	and you should have a fully functional environment in which to do
	293	this tutorial in a matter of minutes.
d442cc9f	294
	295	=over 4
	296
	297	=item *
	298
1def4a20	299	Download Ubuntu 8.04 (aka, Hardy Heron) and boot from the CD and/or
	300	image file, select your language, and then "Try Ubuntu without any
	301	changes to your computer."
	302
	303	=item *
	304
	305	Open a terminal session.
	306
	307	=item *
	308
	309	Add the 'universe' repositories:
	310
	311	sudo vi /etc/apt/sources.list
	312
	313	And remove the comments from the lines under the comments about the
	314	'universe' repositories.
	315
	316	=item *
	317
	318	Install Catalyst:
	319
	320	sudo apt-get update
	321	sudo apt-get upgrade
	322	sudo apt-get install sqlite3 libdbd-sqlite3-perl libcatalyst-perl libcatalyst-modules-perl
	323
	324	Accept all of the dependencies. Done.
	325
	326	=back
	327
	328	=item *
	329
d442cc9f	330	Matt Trout's C<cat-install>
	331
	332	Available at L<http://www.shadowcatsystems.co.uk/static/cat-install>,
	333	C<cat-install> can be a quick and painless way to get Catalyst up and
	334	running. Just download the script from the link above and type C<perl
	335	cat-install>.
	336
	337	=item *
	338
	339	Chris Laco's CatInABox
	340
	341	Download the tarball from
	342	L<http://handelframework.com/downloads/CatInABox.tar.gz> and unpack it
	343	on your machine. Depending on your OS platform, either run C<start.bat>
	344	or C<start.sh>.
	345
	346	=item *
	347
	348	Pre-Built VMWare Images
	349
	350	Under the VMWare community program, work is ongoing to develop a number
	351	of VMWare images where an entire Catalyst development environment has
	352	already been installed, complete with database engines and a full
	353	complement of Catalyst plugins.
	354
	355	=back
	356
	357	For additional information and recommendations on Catalyst installation,
	358	please refer to
	359	L<Catalyst::Manual::Installation\|Catalyst::Manual::Installation>.
	360
	361	B<NOTE:> Step-by-step instructions to replicate the environment on
	362	which this tutorial was developed can be found at
	363	L<Catalyst::Manual::Installation::CentOS4\|Catalyst::Manual::Installation::CentOS4>.
	364	Using these instructions, you should be able to build a complete CentOS
	365	4.X server with Catalyst and all the plugins required to run this
	366	tutorial.
	367
	368	=head1 DATABASES
	369
	370	This tutorial will primarily focus on SQLite because of its simplicity
	371	of installation and use; however, modifications in the script required
	372	to support MySQL and PostgreSQL will be presented in Appendix 2.
	373
	374	B<Note:> One of the advantages of the MVC design patterns is that
	375	applications become much more database independent. As such, you will
	376	notice that only the C<.sql> files used to initialize the database
	377	change between database systems: the Catalyst code generally remains the
	378	same.
	379
	380	=head1 WHERE TO GET WORKING CODE
	381
	382	Each part of the tutorial has complete code available in the main
	383	Catalyst Subversion repository (see the note at the beginning of each
	384	part for the appropriate svn command to use). Additionally, the final
	385	code is available as a ready-to-run tarball at
	386	L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/Tutorial/Final_Tarball/MyApp.tgz>.
	387
	388	B<NOTE:> You can run the test cases for the final code with the following
	389	commands:
	390
	391	wget http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/Tutorial/Final_Tarball/MyApp.tgz
	392	tar zxvf MyApp.tgz
	393	cd MyApp
394	CATALYST_DEBUG=0 prove --lib lib t
395
396
397	=head1 AUTHOR
398
399	Kennedy Clark, C<hkclark@gmail.com>
400
401	Please report any errors, issues or suggestions to the author. The
402	most recent version of the Catalyst Tutorial can be found at
d712b826	403	L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/Catalyst-Manual/lib/Catalyst/Manual/Tutorial/>.
d442cc9f	404
	405	Copyright 2006, Kennedy Clark, under Creative Commons License
	406	(L<http://creativecommons.org/licenses/by-nc-sa/2.5/>).
	407
	408