--- /dev/null
+.\" 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::Manual::Unsweetened 3"
+.TH Moose::Manual::Unsweetened 3 "2009-05-05" "perl v5.8.7" "User Contributed Perl Documentation"
+.SH "NAME"
+Moose::Manual::Unsweetened \- Moose idioms in plain old Perl 5 without the sugar
+.SH "DESCRIPTION"
+.IX Header "DESCRIPTION"
+If you're trying to figure out just what the heck Moose does, and how
+it saves you time, you might find it helpful to see what Moose is
+\&\fIreally\fR doing for you. This document shows you the translation from
+Moose sugar back to plain old Perl 5.
+.SH "CLASSES AND ATTRIBUTES"
+.IX Header "CLASSES AND ATTRIBUTES"
+First, we define two very small classes the Moose way.
+.PP
+.Vb 1
+\& package Person;
+.Ve
+.PP
+.Vb 4
+\& use DateTime;
+\& use DateTime::Format::Natural;
+\& use Moose;
+\& use Moose::Util::TypeConstraints;
+.Ve
+.PP
+.Vb 5
+\& has name => (
+\& is => 'rw',
+\& isa => 'Str',
+\& required => 1,
+\& );
+.Ve
+.PP
+.Vb 2
+\& # Moose doesn't know about non\-Moose\-based classes.
+\& class_type 'DateTime';
+.Ve
+.PP
+.Vb 4
+\& my $en_parser = DateTime::Format::Natural\->new(
+\& lang => 'en',
+\& time_zone => 'UTC',
+\& );
+.Ve
+.PP
+.Vb 3
+\& coerce 'DateTime'
+\& => from 'Str'
+\& => via { $en_parser\->parse_datetime($_) };
+.Ve
+.PP
+.Vb 6
+\& has birth_date => (
+\& is => 'rw',
+\& isa => 'DateTime',
+\& coerce => 1,
+\& handles => { birth_year => 'year' },
+\& );
+.Ve
+.PP
+.Vb 4
+\& subtype 'ShirtSize'
+\& => as 'Str'
+\& => where { /^(?:s|m|l|xl|xxl)$/i }
+\& => message { "$_ is not a valid shirt size (s, m, l, xl, xxl)" };
+.Ve
+.PP
+.Vb 5
+\& has shirt_size => (
+\& is => 'rw',
+\& isa => 'ShirtSize',
+\& default => 'l',
+\& );
+.Ve
+.PP
+This is a fairly simple class with three attributes. We also define a
+type to validate t\-shirt sizes because we don't want to end up with
+something like \*(L"blue\*(R" for the shirt size!
+.PP
+.Vb 1
+\& package User;
+.Ve
+.PP
+.Vb 3
+\& use Email::Valid;
+\& use Moose;
+\& use Moose::Util::TypeConstraints;
+.Ve
+.PP
+.Vb 1
+\& extends 'Person';
+.Ve
+.PP
+.Vb 4
+\& subtype 'Email'
+\& => as 'Str'
+\& => where { Email::Valid\->address($_) }
+\& => message { "$_ is not a valid email address" };
+.Ve
+.PP
+.Vb 5
+\& has email_address => (
+\& is => 'rw',
+\& isa => 'Email',
+\& required => 1,
+\& );
+.Ve
+.PP
+This class subclasses Person to add a single attribute, email address.
+.PP
+Now we will show what these classes would look like in plain old Perl
+5. For the sake of argument, we won't use any base classes or any
+helpers like \f(CW\*(C`Class::Accessor\*(C'\fR.
+.PP
+.Vb 1
+\& package Person;
+.Ve
+.PP
+.Vb 2
+\& use strict;
+\& use warnings;
+.Ve
+.PP
+.Vb 3
+\& use Carp qw( confess );
+\& use DateTime;
+\& use DateTime::Format::Natural;
+.Ve
+.PP
+.Vb 3
+\& sub new {
+\& my $class = shift;
+\& my %p = ref $_[0] ? %{ $_[0] } : @_;
+.Ve
+.PP
+.Vb 3
+\& exists $p{name}
+\& or confess 'name is a required attribute';
+\& $class\->_validate_name( $p{name} );
+.Ve
+.PP
+.Vb 2
+\& exists $p{birth_date}
+\& or confess 'birth_date is a required attribute';
+.Ve
+.PP
+.Vb 2
+\& $p{birth_date} = $class\->_coerce_birth_date( $p{birth_date} );
+\& $class\->_validate_birth_date( $p{birth_date} );
+.Ve
+.PP
+.Vb 2
+\& $p{shirt_size} = 'l'
+\& unless exists $p{shirt_size}:
+.Ve
+.PP
+.Vb 1
+\& $class\->_validate_shirt_size( $p{shirt_size} );
+.Ve
+.PP
+.Vb 2
+\& return bless \e%p, $class;
+\& }
+.Ve
+.PP
+.Vb 3
+\& sub _validate_name {
+\& shift;
+\& my $name = shift;
+.Ve
+.PP
+.Vb 1
+\& local $Carp::CarpLevel = $Carp::CarpLevel + 1;
+.Ve
+.PP
+.Vb 3
+\& defined $name
+\& or confess 'name must be a string';
+\& }
+.Ve
+.PP
+.Vb 5
+\& {
+\& my $en_parser = DateTime::Format::Natural\->new(
+\& lang => 'en',
+\& time_zone => 'UTC',
+\& );
+.Ve
+.PP
+.Vb 3
+\& sub _coerce_birth_date {
+\& shift;
+\& my $date = shift;
+.Ve
+.PP
+.Vb 1
+\& return $date unless defined $date && ! ref $date;
+.Ve
+.PP
+.Vb 1
+\& my $dt = $en_parser\->parse_datetime($date);
+.Ve
+.PP
+.Vb 3
+\& return $dt ? $dt : undef;
+\& }
+\& }
+.Ve
+.PP
+.Vb 3
+\& sub _validate_birth_date {
+\& shift;
+\& my $birth_date = shift;
+.Ve
+.PP
+.Vb 1
+\& local $Carp::CarpLevel = $Carp::CarpLevel + 1;
+.Ve
+.PP
+.Vb 3
+\& $birth_date\->isa('DateTime')
+\& or confess 'birth_date must be a DateTime object';
+\& }
+.Ve
+.PP
+.Vb 3
+\& sub _validate_shirt_size {
+\& shift;
+\& my $shirt_size = shift;
+.Ve
+.PP
+.Vb 1
+\& local $Carp::CarpLevel = $Carp::CarpLevel + 1;
+.Ve
+.PP
+.Vb 2
+\& defined $shirt_size
+\& or confess 'shirt_size cannot be undef';
+.Ve
+.PP
+.Vb 3
+\& $shirt_size =~ /^(?:s|m|l|xl|xxl)$/
+\& or confess "$shirt_size is not a valid shirt size (s, m, l, xl, xxl)";
+\& }
+.Ve
+.PP
+.Vb 2
+\& sub name {
+\& my $self = shift;
+.Ve
+.PP
+.Vb 4
+\& if (@_) {
+\& $self\->_validate_name( $_[0] );
+\& $self\->{name} = $_[0];
+\& }
+.Ve
+.PP
+.Vb 2
+\& return $self\->{name};
+\& }
+.Ve
+.PP
+.Vb 2
+\& sub birth_date {
+\& my $self = shift;
+.Ve
+.PP
+.Vb 3
+\& if (@_) {
+\& my $date = $self\->_coerce_birth_date( $_[0] );
+\& $self\->_validate_birth_date( $date );
+.Ve
+.PP
+.Vb 2
+\& $self\->{birth_date} = $date;
+\& }
+.Ve
+.PP
+.Vb 2
+\& return $self\->{birth_date};
+\& }
+.Ve
+.PP
+.Vb 2
+\& sub birth_year {
+\& my $self = shift;
+.Ve
+.PP
+.Vb 2
+\& return $self\->birth_date\->year;
+\& }
+.Ve
+.PP
+.Vb 2
+\& sub shirt_size {
+\& my $self = shift;
+.Ve
+.PP
+.Vb 4
+\& if (@_) {
+\& $self\->_validate_shirt_size( $_[0] );
+\& $self\->{shirt_size} = $_[0];
+\& }
+.Ve
+.PP
+.Vb 2
+\& return $self\->{shirt_size};
+\& }
+.Ve
+.PP
+Wow, that was a mouthful! One thing to note is just how much space the
+data validation code consumes. As a result, it's pretty common for
+Perl 5 programmers to just not bother. Unfortunately, not validating
+arguments leads to surprises down the line (\*(L"why is birth_date an
+email address?\*(R").
+.PP
+Also, did you spot the (intentional) bug?
+.PP
+It's in the \f(CW\*(C`_validate_birth_date()\*(C'\fR method. We should check that
+the value in \f(CW$birth_date\fR is actually defined and an object before
+we go and call \f(CW\*(C`isa()\*(C'\fR on it! Leaving out those checks means our data
+validation code could actually cause our program to die. Oops.
+.PP
+Note that if we add a superclass to Person we'll have to change the
+constructor to account for that.
+.PP
+(As an aside, getting all the little details of what Moose does for
+you just right in this example was really not easy, which emphasizes
+the point of the example. Moose saves you a lot of work!)
+.PP
+Now let's see User:
+.PP
+.Vb 1
+\& package User;
+.Ve
+.PP
+.Vb 2
+\& use strict;
+\& use warnings;
+.Ve
+.PP
+.Vb 3
+\& use Carp qw( confess );
+\& use Email::Valid;
+\& use Scalar::Util qw( blessed );
+.Ve
+.PP
+.Vb 1
+\& use base 'Person';
+.Ve
+.PP
+.Vb 3
+\& sub new {
+\& my $class = shift;
+\& my %p = ref $_[0] ? %{ $_[0] } : @_;
+.Ve
+.PP
+.Vb 3
+\& exists $p{email_address}
+\& or confess 'email_address is a required attribute';
+\& $class\->_validate_email_address( $p{email_address} );
+.Ve
+.PP
+.Vb 1
+\& my $self = $class\->SUPER::new(%p);
+.Ve
+.PP
+.Vb 1
+\& $self\->{email_address} = $p{email_address};
+.Ve
+.PP
+.Vb 2
+\& return $self;
+\& }
+.Ve
+.PP
+.Vb 3
+\& sub _validate_email_address {
+\& shift;
+\& my $email_address = shift;
+.Ve
+.PP
+.Vb 1
+\& local $Carp::CarpLevel = $Carp::CarpLevel + 1;
+.Ve
+.PP
+.Vb 2
+\& defined $email_address
+\& or confess 'email_address must be a string';
+.Ve
+.PP
+.Vb 3
+\& Email::Valid\->address($email_address)
+\& or confess "$email_address is not a valid email address";
+\& }
+.Ve
+.PP
+.Vb 2
+\& sub email_address {
+\& my $self = shift;
+.Ve
+.PP
+.Vb 4
+\& if (@_) {
+\& $self\->_validate_email_address( $_[0] );
+\& $self\->{email_address} = $_[0];
+\& }
+.Ve
+.PP
+.Vb 2
+\& return $self\->{email_address};
+\& }
+.Ve
+.PP
+That one was shorter, but it only has one attribute.
+.PP
+Between the two classes, we have a whole lot of code that doesn't do
+much. We could probably simplify this by defining some sort of
+\&\*(L"attribute and validation\*(R" hash, like this:
+.PP
+.Vb 1
+\& package Person;
+.Ve
+.PP
+.Vb 14
+\& my %Attr = (
+\& name => {
+\& required => 1,
+\& validate => sub { defined $_ },
+\& },
+\& birth_date => {
+\& required => 1,
+\& validate => sub { blessed $_ && $_\->isa('DateTime') },
+\& },
+\& shirt_size => {
+\& required => 1,
+\& validate => sub { defined $_ && $_ =~ /^(?:s|m|l|xl|xxl)$/i },
+\& }
+\& );
+.Ve
+.PP
+Then we could define a base class that would accept such a definition,
+and do the right thing. Keep that sort of thing up and we're well on
+our way to writing a half-assed version of Moose!
+.PP
+Of course, there are \s-1CPAN\s0 modules that do some of what Moose does,
+like \f(CW\*(C`Class::Accessor\*(C'\fR, \f(CW\*(C`Class::Meta\*(C'\fR, and so on. But none of them
+put together all of Moose's features along with a layer of declarative
+sugar, nor are these other modules designed for extensibility in the
+same way as Moose. With Moose, it's easy to write a MooseX module to
+replace or extend a piece of built-in functionality.
+.PP
+Moose is a complete \s-1OO\s0 package in and of itself, and is part of a rich
+ecosystem of extensions. It also has an enthusiastic community of
+users, and is being actively maintained and developed.
+.SH "AUTHOR"
+.IX Header "AUTHOR"
+Dave Rolsky <autarch@urth.org>
+.SH "COPYRIGHT AND LICENSE"
+.IX Header "COPYRIGHT AND LICENSE"
+Copyright 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.
projects / catagits/Gitalist.git / blobdiff