+
- Calls
Person->BUILDARGS(@_) to turn @_ into a hashref
- Blesses a reference
- Populates attributes based on the hashref from #1
- - Calls
$new_object->BUILDALL($constructor_args)
+ - Calls
$new_object->BUILDALL($constructor_args)
... which calls all BUILD methods
- Returns the object
@@ -957,6 +968,7 @@ sub BUILD {
- Technically it's a hash reference
- If you ever treat it as one you are doing it wrong!
+ - Moose probably provides a feature to do what you need
@@ -966,6 +978,7 @@ sub BUILD {
- Like
DESTROY, but Moose makes sure all DEMOLISH methods in a hierarchy are called
- Called in normal inheritance order, children to parents
+ - Never called by you, only by Perl itself
@@ -1029,6 +1042,7 @@ extends 'LWP';
override is another method modifier- An alternative to Perl's
SUPER::
+ - Declares your intent to override a method
@@ -1040,13 +1054,13 @@ use Moose;
extends 'Person';
-override work => sub {
+override work => sub {
my $self = shift;
die "Pay me first"
unless $self->got_paid;
- super();
-};
+ super();
+};
@@ -1055,7 +1069,8 @@ use Moose;
- Mostly like
$self->SUPER::work(@_)
- But cannot change
@_!
- - Binds the parent's method at compile time
+ - Binds the parent's method correctly at compile time
+ - Parent determined by checking
Child->meta()->superclasses()
- Not very hygienic
@@ -1131,17 +1145,31 @@ use Moose;
...
-no Moose;
+no Moose;
# false
-Person->can('extends');
+Person->can('extends');
+
+
+
+
Cleaning Up Moose Droppings
+
+
package Person;
+use Moose;
+use namespace::autoclean;
+
+...
+
+# false
+Person->can('extends');
No Moose
- no Moose at the end of a package is a best practice- Cleaning up is a best practice
+ - Say
no Moose at the end of a package
- Or
use namespace::autoclean at the top
- Just do it
@@ -1151,13 +1179,13 @@ Person->can('extends');
Immutability
- - Stevan's Incantation of Fleet-Footedness
+ - Stevan's Incantation of Fleet-Footedness
package Person;
use Moose;
-__PACKAGE__->meta->make_immutable;
+
__PACKAGE__->meta->make_immutable;
@@ -1208,6 +1236,8 @@ use Moose;
# perl install-moose (if needed)
+## Read the instructions in t/01-classes.t
+
# perl bin/prove -lv t/01-classes.t
# edit lib/Person.pm and lib/Employee.pm
@@ -1279,23 +1309,25 @@ sub print {
package Person;
use Moose;
-with 'HasPermissions';
+with 'Printable';
Classes Consume Roles
-
my $person = Person->new(
+package Person;
+
+sub as_string { $_[0]->first_name() }
+
+...
+
+my $person = Person->new(
first_name => 'Kenichi',
last_name => 'Asai',
access_level => 42,
);
-print $person->full_name
- . ' has '
- . $person->can_access(42)
- ? 'great power'
- : 'little power';
+$person->print();
@@ -1312,7 +1344,9 @@ print $person->full_name
package Person;
use Moose;
-with 'Printable';
+
with 'Printable';
+
+sub as_string { $_[0]->first_name() }
@@ -1323,6 +1357,8 @@ use Moose;
with 'Printable';
+sub as_string { $_[0]->first_name() }
+
has has_been_printed => ( is => 'rw' );
sub print {
@@ -1343,7 +1379,7 @@ sub print {
# or ...
-Person->meta->does('Printable')
+Person->meta->does_role('Printable')
@@ -1403,69 +1439,17 @@ use Moose;
-
Method Aliasing
-
-
package FragileDancer;
-use Moose;
-
-with 'IsFragile' =>
- { -alias =>
- { break => 'break_bone' } },
- 'CanBreakdance' =>
- { -alias =>
- { break => 'break_it_down' } };
-
-
- - Renames the roles' methods
- - Still conflicts, need to
exclude as well
-
-
-
Method Exclusion
-
-
package FragileDancer;
-use Moose;
-
-with 'IsFragile' =>
- { -alias =>
- { break => 'break_bone' },
- -excludes => 'break' },
- 'CanBreakdance' =>
- { -alias =>
- { break => 'break_it_down' },
- -excludes => 'break' };
-
-
And then ...
-
-
package FragileDancer;
-use Moose;
-
-sub break {
- my $self = shift;
-
- $self->break_it_down;
- if ( rand(1) < 0.5 ) {
- $self->break_bone;
- }
-}
-
-
Still Full of Fail
+
Conflicts Are a Smell
- - Roles are also about semantics!
- - We've fulfilled the letter and lost the spirit
+ - Roles are about semantics!
- Roles have a meaning
- - Think twice before blindly aliasing and excluding methods!
+ - Method name conflicts smell like bad design
-
Hot Role-on-Role Action
+
Roles With Roles
package Comparable;
use Moose::Role;
@@ -1474,7 +1458,7 @@ requires 'compare';
-
Hot Role-on-Role Action
+
Roles With Roles
package TestsEquality;
use Moose::Role;
@@ -1483,7 +1467,7 @@ with 'Comparable';
sub is_equal {
my $self = shift;
- return $self->compare(@_) == 0;
+ return $self->compare(@_) == 0;
}
-
Name Conflicts Between Roles
-
-
package HasSubProcess;
-use Moose::Role;
-
-sub execute { ... }
-
-package Killer;
-use Moose::Role;
-
-with 'HasSubProcess';
-
-sub execute { ... }
-
-
Delayed Conflict
-
-
package StateOfTexas;
-with 'Killer';
-
-
- StateOfTexas must implement its own execute- But loading the
Killer role by itself does not cause an error
-
+Integer->does('TestsEquality'); # true
+Integer->does('Comparable'); # also true!
@@ -1553,7 +1509,7 @@ use Moose;
with 'HasSize';
-has size => ( is => 'ro' );
+has size => ( is => 'ro' );
@@ -1567,7 +1523,7 @@ requires 'size';
package Shirt;
use Moose;
-has size => ( is => 'ro' );
+has size => ( is => 'ro' );
with 'HasSize';
@@ -1589,9 +1545,9 @@ with 'HasSize';
package Comparison;
use Moose;
-has [ 'left', 'right' ] => (
- is => 'ro',
- does => 'Comparable',
+has [ 'left', 'right' ] => (
+ is => 'ro',
+ does => 'Comparable',
);
@@ -1606,7 +1562,7 @@ has [ 'left', 'right' ] => (
use Moose::Util qw( apply_all_roles );
-my $fragile_person = Person->new( ... );
+my $fragile_person = Person->new( ... );
apply_all_roles( $fragile_person,
'IsFragile' );
@@ -1680,8 +1636,6 @@ requires 'compare';
Real Examples
- - Column and ColumnAlias both do ColumnLike
- - ColumnLike things can be used in certain parts of queries
- All queries do HasWhereClause
- Select does Comparable and Selectable (for subselects)
- A where clause requires its components to do Comparable
@@ -1743,6 +1697,15 @@ has 'is_ripped' => ( is => 'rw' );
+
Read-only vs Read-write
+
+
+ - Read-only is preferred
+ - Minimize state in your application
+
+
Required-ness
@@ -1762,8 +1725,8 @@ has first_name => (
required => 1,
);
-Person->new( first_name => undef ); # ok
-Person->new(); # kaboom
+Person->new( first_name => undef ); # ok
+Person->new(); # kaboom
@@ -1828,6 +1791,7 @@ use Moose;
has bank => (
is => 'rw',
+ # THIS WILL NOT WORK
default => Bank->new(
name => 'Spire FCU' ),
);
@@ -1850,25 +1814,11 @@ has packages => (
-
What if I Want to Share?
-
-
package Person;
-use Moose;
-
-my $highlander_bank =
- Bank->new( name => 'Spire FCU' );
-
-has bank => (
- is => 'rw',
- default => sub { $highlander_bank },
-);
-
Builder
- - A method name which returns the default
+ - A method name
+ - When called, this method returns the default value
@@ -1886,7 +1836,7 @@ has bank => (
sub _build_bank {
my $self = shift;
return Bank->new(
- name => 'Spire FCU' );
+ name => 'Spire FCU' );
}
@@ -1942,7 +1892,8 @@ has bank => (
use Moose;
has shoe_size => (
- is => 'ro',
+ is => 'ro',
+ required => 1,
);
@@ -1952,7 +1903,7 @@ has shoe_size => (
has shoes => (
is => 'ro',
lazy => 1,
- builder => '_build_shoes',
+ builder => '_build_shoes',
);
sub _build_shoes {
@@ -2025,16 +1976,16 @@ has account => (
package Person;
use Moose;
-has shoe_size => (
+has shoe_size => (
is => 'ro',
init_arg => 'foot_size',
);
-Person->new( shoe_size => 13 );
+Person->new( shoe_size => 13 );
my $person =
- Person->new( foot_size => 13 );
-print $person->shoe_size;
+ Person->new( foot_size => 13 );
+print $person->shoe_size;
@@ -2043,12 +1994,12 @@ print $person->shoe_size;
package Person;
use Moose;
-has shoes => (
+has shoes => (
is => 'ro',
init_arg => undef,
);
-Person->new( shoes => Shoes->new );
+Person->new(
shoes => Shoes->new );
@@ -2067,15 +2018,7 @@ Person->new(
shoes => Shoes->new );
- By default, subclasses inherit attribute as-is
-
- Can change some attribute parameters in subclasses
-
- - default
- - builder
- - required
- - lazy
- - others we've not yet covered
-
-
+
- Can change attribute parameters in subclasses
- Attributes can have a
default or builder
- Attributes with a default or builder can be
lazy
- Attributes can have a
clearer and/or predicate
+
+
+
+
+
Basic Attributes Summary
+
+
- An attribute's constructor name can be changed with
init_arg
- A subclass can alter its parents' attributes
- Attribute accessor names can be changed
@@ -2224,18 +2174,18 @@ Iterate til this passes all its tests
- Apply to an existing method
- - ... from a parent class, the current class, or a role
+ - ... that comes from a parent class, the current class, or a role
- Roles can provide modifiers that are applied at composition time
-
What is a Method Modifier
+
What Are Method Modifiers For?
- "Inject" behavior
- Add behavior to generated methods (accessors, delegations)
- - Provide roles which modify existing behavior
+ - Added from a role, can modify existing behavior
-
Augment and Inner
-
-
- - Inverted
super
- - From least- to most-specific
- - Grandparent to parent to child
- - Not allowed in roles
-
-
-
Augment and Inner
-
-
package Document;
-
-sub xml { '<doc>' . inner() . '</doc>' }
-
-package Report;
-extends 'Document';
-augment xml =>
- sub { title() . inner() . summary() };
-
-package TPSReport;
-extends 'Report';
-augment xml =>
- sub { tps_xml() . inner() };
-
-
Augment and Inner
-
-
- - When we call
$tps->xml ...
-
- Document->xmlReport->xmlTPSReport->xml
-
-
-
-
Augment and Inner Usage
-
-
- - Call
inner() to "fill in the blank"
- - Requires designing for subclassing
- - Call
inner() in the terminal class, just in case
-
-
Method Modifiers Summary
@@ -2499,21 +2396,7 @@ extends 'Report';
- not call the original method at all (or call a different method)
-
-
-
-
-
Method Modifiers Summary
-
-
- When using modifiers in a role, require the modified method
- - Use
augment and inner to invert the normal subclassing flow ...
-
- - Least- to most-specific (parents to children)
- - Build in "insertability" (stick more stuff in the "middle")
-
-
- - Always call
inner in the most specific subclass to allow for future extension
Bool
True
- 1
-924.1
-'true'
-{}
+ 1
False
0
-0.0
'0'
+''
undef
@@ -2621,6 +2501,7 @@ undef
Value is true when ! ref $thingValue and Str are effectively the same, but Str is more expressiveNum is true when a $scalar looks like a number- An overloaded object which numifies does not pass the
Num constraint!
- Perl 5's overloading is hopelessly broken
@@ -2721,9 +2602,11 @@ has start_date => (
Subtype Shortcuts - class_type
use Moose::Util::TypeConstraints;
-class_type 'DateTime';
+class_type 'DateTime';
+
+
-subtype 'DateTime',
+subtype 'DateTime',
as 'Object',
where { $_->isa('DateTime') },
message { ... };
@@ -2733,10 +2616,12 @@ subtype 'DateTime',
Subtype Shortcuts - role_type
use Moose::Util::TypeConstraints;
-role_type 'Printable';
+role_type 'Printable';
-subtype 'Printable',
- as 'Object',
+
+
+subtype 'Printable',
+ as 'Object',
where
{ Moose::Util::does_role(
$_, 'Printable' ) },
@@ -2747,9 +2632,11 @@ subtype 'Printable',
Subtype Shortcuts - duck_type
use Moose::Util::TypeConstraints;
-duck_type Car => qw( run break_down );
+duck_type Car => qw( run break_down );
+
+
-subtype 'Car',
+subtype 'Car',
as 'Object',
where { all { $_->can($_) }
qw( run break_down ) },
@@ -2760,12 +2647,14 @@ subtype 'Car',
Subtype Shortcuts - enum
use Moose::Util::TypeConstraints;
-enum Color => qw( red blue green ) );
+enum Color => qw( red blue green );
+
+
-my %ok = map { $_ => 1 }
+my %ok = map { $_ => 1 }
qw( red blue green );
-subtype 'Color'
+subtype 'Color'
as 'Str',
where { $ok{$_} },
message { ... };
@@ -2836,7 +2725,8 @@ coerce 'My::DateTime',
Coercion Examples
-
coerce 'ArrayRef[Int]',
+ # BAD CODE - DO NOT COPY
+coerce 'ArrayRef[Int]',
from 'Int',
via { [ $_ ] };
@@ -2881,6 +2771,19 @@ no Moose;
+
Questions So Far?
+
+
+
+
Exercises
+
+
# cd exercises
+# perl bin/prove -lv t/05-types.t
+
+Iterate til this passes all its tests
+
Typed Methods (Low-tech)
package Person;
@@ -2921,7 +2824,7 @@ sub work {
Digression: The Type Registry
- - Types are actually
Moose::Meta::TypeConstraints objects
+ - Types are actually
Moose::Meta::TypeConstraint objects
- Stored in an interpreter-global registry mapping names to objects
@@ -3011,9 +2914,9 @@ coerce ArrayOfInt
use MyApp::Types qw( ArrayOfInt );
-has transaction_history => (
- is => 'rw',
- isa => ArrayOfInt,
+has transaction_history => (
+ is => 'rw',
+ isa => ArrayOfInt,
);
@@ -3023,7 +2926,7 @@ has transaction_history => (
- Type names are exported functions, catches typos early
- Types must be pre-declared
- - Types are stored with namespaces internally, but externally are short
+ - Types are stored with namespaces internally, but you use short names
- Import existing Moose types as functions from
MooseX::Types::Moose
- Still need string names for things like
ArrayRef['Email::Address']
@@ -3036,7 +2939,7 @@ has transaction_history => (
- Catches typos at compile time
- Automatic namespacing
- One more thing to install and learn
- - Every name gets types twice (declared and then defined)
+ - Every name is typed twice (declared and then defined)
- Still stuck with strings when referring to class or role names
- Coercion gotcha from earlier still applies to types exported from
MooseX::Types::Moose
@@ -3057,15 +2960,6 @@ has transaction_history => (
Questions?
-
-
Exercises
-
-
# cd exercises
-# perl bin/prove -lv t/05-types.t
-
-Iterate til this passes all its tests
-
Part 6: Advanced Attributes
@@ -3163,7 +3057,7 @@ $alice->friend($bob);
after salary_level => {
my $self = shift;
- return unless @_;
+ return unless @_;
$self->clear_salary;
};
@@ -3175,11 +3069,22 @@ $alice->friend($bob);
has salary_level => (
is => 'rw',
- trigger => sub { $_[0]->clear_salary },
+ trigger =>
+ sub { $_[0]->clear_salary },
);
+
Trigger Arguments
+
+
+ $self$new_value$old_value - if one exists
+
Delegation
@@ -3195,7 +3100,7 @@ $alice->friend($bob);
has lungs => (
is => 'ro',
- isa => 'Lungs',
+ isa => 'Lungs',
handles => [ 'inhale', 'exhale' ],
);
@@ -3236,6 +3141,7 @@ has lungs => (
Array Reference
+ - 1-to-1 mapping
- Takes each method name and creates a simple delegation from the delegating class to the delegatee attribute
@@ -3358,7 +3264,6 @@ has history => (
use Moose;
has _favorite_numbers => (
traits => [ 'Array' ],
- is => 'ro',
isa => 'ArrayRef[Int]',
default => sub { [] },
init_arg => undef,
@@ -3396,7 +3301,7 @@ print "$_\n"
- Bool -
set, toggle, ...
- Hash -
get, set, ...
- Array - already saw it
- - Code -
execute, that's it
+ - Code -
execute and execute_method
@@ -3421,7 +3326,7 @@ has account => (
isa => 'BankAccount',
handles => {
receive_100 =>
- [ 'deposit', 100 ]
+ [ 'deposit', 100 ],
give_100 =>
[ 'withdraw', 100 ]
},
@@ -3461,7 +3366,7 @@ $person->account->deposit(100);
Traits and Metaclasses
- - Can add/alter/remove attribute parameter (from
has)
+ - Can add/alter/remove an attribute parameter (from
has)
- Can change behavior of created attribute
@@ -3519,6 +3424,7 @@ print Person->meta
- Use
weak_ref to avoid circular references
- Use trigger to do an action post-attribute write
- Use delegations to hide "internal" objects
+ - Use native delegations to treat Perl types as objects
- Traits and metaclasses let you extend Moose's core attribute features
@@ -3537,12 +3443,20 @@ print Person->meta
Iterate til this passes all its tests
-
-
Part 7: Introspection
+
+
CYOA
+
+
+ If there is time, keep going ...
+
+
+
+ Otherwise, jump to slide 269 ...
+
-
Part 8: A Brief Tour of MooseX
+ Bonus: A Brief Tour of MooseX
@@ -3550,7 +3464,7 @@ Iterate til this passes all its tests
- Not comprehensive
- - 128 MooseX distributions on CPAN as of 09/24/2009
+ - 188 MooseX distributions on CPAN as of 02/03/2011
- Some of them are crap
@@ -3559,11 +3473,11 @@ Iterate til this passes all its tests
Already Mentioned Several
- - MooseX::NonMoose - best solution for subclassing non-Moose parents
- - MooseX::Declare - real Perl 5 OO
- - MooseX::FollowPBP and MooseX::SemiAffordanceAccessor
- - MooseX::Params::Validate and MooseX::Method::Signatures
- - MooseX::Types
+ MooseX::NonMoose - best solution for subclassing non-Moose parentsMooseX::Declare - real Perl 5 OOMooseX::FollowPBP and MooseX::SemiAffordanceAccessorMooseX::Params::Validate and MooseX::Method::SignaturesMooseX::Types
MooseX::Declare
use MooseX::Declare;
-use 5.10.0; # for say
+use 5.12.0; # for say
class Person {
- has greeting
- => ( is => 'ro', isa => 'Str' );
+ has greeting =>
+ ( is => 'ro', isa => 'Str' );
method speak {
say $self->greeting;
@@ -3590,6 +3504,7 @@ class Person {
- Still experimental-ish, but seeing more and more use
- Not a source filter!
- Hooks into the Perl parser rather than filtering all your code
+ - But not supported by
PPI, perltidy, etc. (yet?)
@@ -3597,7 +3512,7 @@ class Person {
MooseX::StrictConstructor
- - By default, unknown constructor arguments are ignore
+ - By default, unknown constructor arguments are ignored
- MX::StrictConstructor turns these into an error
@@ -3659,7 +3574,7 @@ use Moose;
has file =>
( is => 'ro', required => 1 );
has filters =>
- ( is => 'ro', isa => 'Str' );
+ ( is => 'ro', isa => 'ArrayRef[Str]' );
sub run { ... }
@@ -3675,7 +3590,7 @@ sub run { ... }
use App::CLI;
-App::CLI->new_with_options()->run();
+App::CLI->new_with_options()->run();
$ myapp-cli \
--file foo \
@@ -3735,12 +3650,21 @@ with HasCollection => { type => 'Int' };
Questions?
-
-
Part 9: Writing Moose Extensions
-
+
+
Moose-using Modules
-
-
The End
+
+ For further reading, a few modules which use Moose ...
+
+
+
@@ -3753,10 +3677,14 @@ with HasCollection => { type => 'Int' };
- mailing list - moose@perl.org
- Slides and exercises are in Moose's git repo:
- git://jules.scsys.co.uk/gitmo/moose-presentations
+
git://git.moose.perl.org/moose-presentations.git
+
+
The End
+
+