[catagits/Gitalist.git] / local-lib5 / man / man3 / Moose::Cookbook::Roles::Recipe3.3pm

.\" Automatically generated by Pod::Man v1.37, Pod::Parser v1.3
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sh \" Subsection heading
.br
.if t .Sp
.ne 5
.PP
\fB\\$1\fR
.PP
..
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  | will give a
.\" real vertical bar.  \*(C+ will give a nicer C++.  Capital omega is used to
.\" do unbreakable dashes and therefore won't be available.  \*(C` and \*(C'
.\" expand to `' in nroff, nothing in troff, for use with C<>.
.tr \(*W-|\(bv\*(Tr
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
'br\}
.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.if \nF \{\
.    de IX
.    tm Index:\\$1\t\\n%\t"\\$2"
..
.    nr % 0
.    rr F
.\}
.\"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.hy 0
.if n .na
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "Moose::Cookbook::Roles::Recipe3 3"
.TH Moose::Cookbook::Roles::Recipe3 3 "2009-08-18" "perl v5.8.7" "User Contributed Perl Documentation"
.SH "NAME"
Moose::Cookbook::Roles::Recipe3 \- Applying a role to an object instance
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&  package MyApp::Role::Job::Manager;
.Ve
.PP
.Vb 1
\&  use List::Util qw( first );
.Ve
.PP
.Vb 1
\&  use Moose::Role;
.Ve
.PP
.Vb 4
\&  has 'employees' => (
\&      is  => 'rw',
\&      isa => 'ArrayRef[Employee]',
\&  );
.Ve
.PP
.Vb 3
\&  sub assign_work {
\&      my $self = shift;
\&      my $work = shift;
.Ve
.PP
.Vb 1
\&      my $employee = first { !$_\->has_work } @{ $self\->employees };
.Ve
.PP
.Vb 1
\&      die 'All my employees have work to do!' unless $employee;
.Ve
.PP
.Vb 2
\&      $employee\->work($work);
\&  }
.Ve
.PP
.Vb 1
\&  package main;
.Ve
.PP
.Vb 2
\&  my $lisa = Employee\->new( name => 'Lisa' );
\&  MyApp::Role::Job::Manager\->meta\->apply($lisa);
.Ve
.PP
.Vb 3
\&  my $homer = Employee\->new( name => 'Homer' );
\&  my $bart  = Employee\->new( name => 'Bart' );
\&  my $marge = Employee\->new( name => 'Marge' );
.Ve
.PP
.Vb 2
\&  $lisa\->employees( [ $homer, $bart, $marge ] );
\&  $lisa\->assign_work('mow the lawn');
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
In this recipe, we show how a role can be applied to an object. In
this specific case, we are giving an employee managerial
responsibilities.
.PP
Applying a role to an object is simple. The Moose::Meta::Role
object provides an \f(CW\*(C`apply\*(C'\fR method. This method will do the right
thing when given an object instance.
.PP
.Vb 1
\&  MyApp::Role::Job::Manager\->meta\->apply($lisa);
.Ve
.PP
We could also use the \f(CW\*(C`apply_all_roles\*(C'\fR function from Moose::Util.
.PP
.Vb 1
\&  apply_all_roles( $person, MyApp::Role::Job::Manager\->meta );
.Ve
.PP
The main advantage of using \f(CW\*(C`apply_all_roles\*(C'\fR is that it can be used
to apply more than one role at a time.
.PP
We could also pass parameters to the role we're applying:
.PP
.Vb 4
\&  MyApp::Role::Job::Manager\->meta\->apply(
\&      $lisa,
\&      \-alias => { assign_work => 'get_off_your_lazy_behind' },
\&  );
.Ve
.PP
We saw examples of how method exclusion and alias working in roles recipe 2.
.SH "CONCLUSION"
.IX Header "CONCLUSION"
Applying a role to an object instance is a useful tool for adding
behavior to existing objects. In our example, it is effective used to
model a promotion.
.PP
It can also be useful as a sort of controlled monkey-patching for
existing code, particularly non-Moose code. For example, you could
create a debugging role and apply it to an object at runtime.
.SH "AUTHOR"
.IX Header "AUTHOR"
Dave Rolsky <autarch@urth.org>
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
Copyright 2006\-2009 by Infinity Interactive, Inc.
.PP
<http://www.iinteractive.com>
.PP
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
Commit	Line	Data
3fea05b9	1	.\" Automatically generated by Pod::Man v1.37, Pod::Parser v1.3
	2	.\"
	3	.\" Standard preamble:
	4	.\" ========================================================================
	5	.de Sh \" Subsection heading
	6	.br
	7	.if t .Sp
	8	.ne 5
	9	.PP
	10	\fB\\$1\fR
	11	.PP
	12	..
	13	.de Sp \" Vertical space (when we can't use .PP)
	14	.if t .sp .5v
	15	.if n .sp
	16	..
	17	.de Vb \" Begin verbatim text
	18	.ft CW
	19	.nf
	20	.ne \\$1
	21	..
	22	.de Ve \" End verbatim text
	23	.ft R
	24	.fi
	25	..
	26	.\" Set up some character translations and predefined strings. \*(-- will
	27	.\" give an unbreakable dash, \(PI will give pi, \(L" will give a left
	28	.\" double quote, and \*(R" will give a right double quote. \| will give a
	29	.\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used to
	30	.\" do unbreakable dashes and therefore won't be available. \(C` and \(C'
	31	.\" expand to `' in nroff, nothing in troff, for use with C<>.
	32	.tr \(W-\|\(bv\(Tr
	33	.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
	34	.ie n \{\
	35	. ds -- \(*W-
	36	. ds PI pi
	37	. if (\n(.H=4u)&(1m=24u) .ds -- \(W\h'-12u'\(W\h'-12u'-\" diablo 10 pitch
	38	. if (\n(.H=4u)&(1m=20u) .ds -- \(W\h'-12u'\(W\h'-8u'-\" diablo 12 pitch
	39	. ds L" ""
	40	. ds R" ""
	41	. ds C` ""
	42	. ds C' ""
	43	'br\}
	44	.el\{\
	45	. ds -- \\|\(em\\|
	46	. ds PI \(*p
	47	. ds L" ``
	48	. ds R" ''
	49	'br\}
	50	.\"
	51	.\" If the F register is turned on, we'll generate index entries on stderr for
	52	.\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index
	53	.\" entries marked with X<> in POD. Of course, you'll have to process the
	54	.\" output yourself in some meaningful fashion.
	55	.if \nF \{\
	56	. de IX
	57	. tm Index:\\$1\t\\n%\t"\\$2"
	58	..
	59	. nr % 0
	60	. rr F
	61	.\}
	62	.\"
	63	.\" For nroff, turn off justification. Always turn off hyphenation; it makes
	64	.\" way too many mistakes in technical documents.
65	.hy 0
66	.if n .na
67	.\"
68	.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
69	.\" Fear. Run. Save yourself. No user-serviceable parts.
70	. \" fudge factors for nroff and troff
71	.if n \{\
72	. ds #H 0
73	. ds #V .8m
74	. ds #F .3m
75	. ds #[ \f1
76	. ds #] \fP
77	.\}
78	.if t \{\
79	. ds #H ((1u-(\\\\n(.fu%2u))*.13m)
80	. ds #V .6m
81	. ds #F 0
82	. ds #[ \&
83	. ds #] \&
84	.\}
85	. \" simple accents for nroff and troff
86	.if n \{\
87	. ds ' \&
88	. ds ` \&
89	. ds ^ \&
90	. ds , \&
91	. ds ~ ~
92	. ds /
93	.\}
94	.if t \{\
95	. ds ' \\k:\h'-(\\n(.wu8/10-\(#H)'\'\h"\|\\n:u"
96	. ds ` \\k:\h'-(\\n(.wu8/10-\(#H)'\`\h'\|\\n:u'
97	. ds ^ \\k:\h'-(\\n(.wu10/11-\(#H)'^\h'\|\\n:u'
98	. ds , \\k:\h'-(\\n(.wu*8/10)',\h'\|\\n:u'
99	. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'\|\\n:u'
100	. ds / \\k:\h'-(\\n(.wu8/10-\(#H)'\z\(sl\h'\|\\n:u'
101	.\}
102	. \" troff and (daisy-wheel) nroff accents
103	.ds : \\k:\h'-(\\n(.wu8/10-\(#H+.1m+\(#F)'\v'-\(#V'\z.\h'.2m+\(#F'.\h'\|\\n:u'\v'\(#V'
104	.ds 8 \h'\(#H'\(b\h'-\*(#H'
105	.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\(#H)/2u'\v'-.3n'\(#[\z\(de\v'.3n'\h'\|\\n:u'\*(#]
106	.ds d- \h'\(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\(#H'
107	.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'\|\\n:u'
108	.ds th \(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u2/3)'\s-1o\s+1\*(#]
109	.ds Th \(#[\s+2I\s-2\h'-\w'I'u3/5'\v'-.3m'o\v'.3m'\*(#]
110	.ds ae a\h'-(\w'a'u*4/10)'e
111	.ds Ae A\h'-(\w'A'u*4/10)'E
112	. \" corrections for vroff
113	.if v .ds ~ \\k:\h'-(\\n(.wu9/10-\(#H)'\s-2\u~\d\s+2\h'\|\\n:u'
114	.if v .ds ^ \\k:\h'-(\\n(.wu10/11-\(#H)'\v'-.4m'^\v'.4m'\h'\|\\n:u'
115	. \" for low resolution devices (crt and lpr)
116	.if \n(.H>23 .if \n(.V>19 \
117	\{\
118	. ds : e
119	. ds 8 ss
120	. ds o a
121	. ds d- d\h'-1'\(ga
122	. ds D- D\h'-1'\(hy
123	. ds th \o'bp'
124	. ds Th \o'LP'
125	. ds ae ae
126	. ds Ae AE
127	.\}
128	.rm #[ #] #H #V #F C
129	.\" ========================================================================
130	.\"
131	.IX Title "Moose::Cookbook::Roles::Recipe3 3"
132	.TH Moose::Cookbook::Roles::Recipe3 3 "2009-08-18" "perl v5.8.7" "User Contributed Perl Documentation"
133	.SH "NAME"
134	Moose::Cookbook::Roles::Recipe3 \- Applying a role to an object instance
135	.SH "SYNOPSIS"
136	.IX Header "SYNOPSIS"
137	.Vb 1
138	\& package MyApp::Role::Job::Manager;
139	.Ve
140	.PP
141	.Vb 1
142	\& use List::Util qw( first );
143	.Ve
144	.PP
145	.Vb 1
146	\& use Moose::Role;
147	.Ve
148	.PP
149	.Vb 4
150	\& has 'employees' => (
151	\& is => 'rw',
152	\& isa => 'ArrayRef[Employee]',
153	\& );
154	.Ve
155	.PP
156	.Vb 3
157	\& sub assign_work {
158	\& my $self = shift;
159	\& my $work = shift;
160	.Ve
161	.PP
162	.Vb 1
163	\& my $employee = first { !$_\->has_work } @{ $self\->employees };
164	.Ve
165	.PP
166	.Vb 1
167	\& die 'All my employees have work to do!' unless $employee;
168	.Ve
169	.PP
170	.Vb 2
171	\& $employee\->work($work);
172	\& }
173	.Ve
174	.PP
175	.Vb 1
176	\& package main;
177	.Ve
178	.PP
179	.Vb 2
180	\& my $lisa = Employee\->new( name => 'Lisa' );
181	\& MyApp::Role::Job::Manager\->meta\->apply($lisa);
182	.Ve
183	.PP
184	.Vb 3
185	\& my $homer = Employee\->new( name => 'Homer' );
186	\& my $bart = Employee\->new( name => 'Bart' );
187	\& my $marge = Employee\->new( name => 'Marge' );
188	.Ve
189	.PP
190	.Vb 2
191	\& $lisa\->employees( [ $homer, $bart, $marge ] );
192	\& $lisa\->assign_work('mow the lawn');
193	.Ve
194	.SH "DESCRIPTION"
195	.IX Header "DESCRIPTION"
196	In this recipe, we show how a role can be applied to an object. In
197	this specific case, we are giving an employee managerial
198	responsibilities.
199	.PP
200	Applying a role to an object is simple. The Moose::Meta::Role
201	object provides an \f(CW\(C`apply\(C'\fR method. This method will do the right
202	thing when given an object instance.
203	.PP
204	.Vb 1
205	\& MyApp::Role::Job::Manager\->meta\->apply($lisa);
206	.Ve
207	.PP
208	We could also use the \f(CW\(C`apply_all_roles\(C'\fR function from Moose::Util.
209	.PP
210	.Vb 1
211	\& apply_all_roles( $person, MyApp::Role::Job::Manager\->meta );
212	.Ve
213	.PP
214	The main advantage of using \f(CW\(C`apply_all_roles\(C'\fR is that it can be used
215	to apply more than one role at a time.
216	.PP
217	We could also pass parameters to the role we're applying:
218	.PP
219	.Vb 4
220	\& MyApp::Role::Job::Manager\->meta\->apply(
221	\& $lisa,
222	\& \-alias => { assign_work => 'get_off_your_lazy_behind' },
223	\& );
224	.Ve
225	.PP
226	We saw examples of how method exclusion and alias working in roles recipe 2.
227	.SH "CONCLUSION"
228	.IX Header "CONCLUSION"
229	Applying a role to an object instance is a useful tool for adding
230	behavior to existing objects. In our example, it is effective used to
231	model a promotion.
232	.PP
233	It can also be useful as a sort of controlled monkey-patching for
234	existing code, particularly non-Moose code. For example, you could
235	create a debugging role and apply it to an object at runtime.
236	.SH "AUTHOR"
237	.IX Header "AUTHOR"
238	Dave Rolsky <autarch@urth.org>
239	.SH "COPYRIGHT AND LICENSE"
240	.IX Header "COPYRIGHT AND LICENSE"
241	Copyright 2006\-2009 by Infinity Interactive, Inc.
242	.PP
243	<http://www.iinteractive.com>
244	.PP
245	This library is free software; you can redistribute it and/or modify
246	it under the same terms as Perl itself.