X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=moose-class%2Fslides%2Findex.html;h=98e190a312cc6d8648c6f7a310e8299b57c392fb;hb=ba3e6f3b43767d159a22c4884f0a7e3720bda4c2;hp=cbbf3a110208ef5fb1df8b2808c65c063efffbc8;hpb=d6c8786deaf97484afa544488d5e0340d131c274;p=gitmo%2Fmoose-presentations.git
diff --git a/moose-class/slides/index.html b/moose-class/slides/index.html
index cbbf3a1..98e190a 100644
--- a/moose-class/slides/index.html
+++ b/moose-class/slides/index.html
@@ -40,7 +40,7 @@ img#me05 {top: 43px;left: 36px;}
@@ -341,7 +354,7 @@ has blog_uri => (
Why Moose?
- - A quick bit of propoganda ...
+ - A quick bit of propaganda ...
@@ -885,10 +898,9 @@ use Moose;
sub BUILDARGS {
my $class = shift;
- if ( @_ == 1 && ! ref $_[0] ) {
+ if ( @_ == 1 && ! ref $_[0] ) {
return { ssn => $_[0] };
}
-
return $class->SUPER::BUILDARGS(@_);
}
@@ -925,6 +937,30 @@ sub BUILD {
+
Object Construction a la Moose
+
+
Person->new(@_)
+
+
+ - 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)
+
... which calls all BUILD methods
+ - Returns the object
+
+
+
The Object is Opaque
+
+
+ - Technically it's a hash reference
+ - If you ever treat it as one you are doing it wrong!
+
+
DEMOLISH
@@ -938,6 +974,8 @@ sub BUILD {
extends is sugar for declaring parent classes- Also ensures metaclass compatibility between parent and child
+ - Do not
use base
package Employee;
@@ -986,26 +1024,27 @@ extends 'LWP';
-
overrides and super
+
override and super
- overrides is another method modifieroverride is another method modifier- An alternative to Perl's
SUPER::
-
overrides and super
+
override and super
package Employee;
use Moose;
extends 'Person';
-overrides work => sub {
+override work => sub {
my $self = shift;
- die "Pay me first" unless $self->got_paid;
+ die "Pay me first"
+ unless $self->got_paid;
super();
};
no Moose at the end of a package is a best practice- Or
use namespace::autoclean at the top
- Just do it
@@ -1148,7 +1188,7 @@ use Moose;
use Moose
Class->meta
Moose::Object base class
- extends, overrides, and super
+ extends, override, and super
Simple attributes: has, is => 'ro', & is => 'rw'
no Moose
__PACKAGE__->meta->make_immutable
@@ -1163,12 +1203,15 @@ use Moose;
Exercises
# cd exercises
-$ perl bin/prove -lv t/00-prereq.t
-Missing anything? Install it. (see tarballs/)
+# perl bin/prove -lv t/00-prereq.t
+
+# perl install-moose (if needed)
# perl bin/prove -lv t/01-classes.t
+# edit lib/Person.pm and lib/Employee.pm
+
Iterate til this passes all its tests
@@ -1186,11 +1229,10 @@ Iterate til this passes all its tests
-
Roles Can Have State and Behavior
+
Roles - State and Behavior
package HasPermissions;
use Moose::Role;
-
# state
has access_level => ( is => 'rw' );
@@ -1199,7 +1241,8 @@ sub can_access {
my $self = shift;
my $required = shift;
- return $self->access_level >= $required;
+ return $self->access_level
+ >= $required;
}
Classes Consume Roles
my $person = Person->new(
- first_name => 'Kenichi',
- last_name => 'Asai',
+ first_name => 'Kenichi',
+ last_name => 'Asai',
access_level => 42,
);
@@ -1300,7 +1343,7 @@ sub print {
# or ...
-if ( Person->meta->does('Printable') ) { ... }
+Person->meta->does('Printable')
@@ -1354,7 +1397,7 @@ use Moose;
Conflict Resolution
- - The consuming class must resolve the conflict by implementing th emethod
+ - The consuming class must resolve the conflict by implementing the method
- Can use some combination of method exclusion and aliasing
@@ -1366,10 +1409,10 @@ use Moose;
use Moose;
with 'IsFragile' =>
- { alias =>
+ { -alias =>
{ break => 'break_bone' } },
'CanBreakdance' =>
- { alias =>
+ { -alias =>
{ break => 'break_it_down' } };
@@ -1385,13 +1428,13 @@ use Moose;
use Moose;
with 'IsFragile' =>
- { alias =>
+ { -alias =>
{ break => 'break_bone' },
- exclude => 'break' },
+ -excludes => 'break' },
'CanBreakdance' =>
- { alias =>
- { break => 'break_dance' },
- exclude => 'break' };
+ { -alias =>
+ { break => 'break_it_down' },
+ -excludes => 'break' };
@@ -1403,7 +1446,7 @@ use Moose;
sub break {
my $self = shift;
- $self->break_dance;
+ $self->break_it_down;
if ( rand(1) < 0.5 ) {
$self->break_bone;
}
@@ -1564,7 +1607,8 @@ has [ 'left', 'right' ] => (
use Moose::Util qw( apply_all_roles );
my $fragile_person = Person->new( ... );
-apply_all_roles( $fragile_person, 'IsFragile' );
+apply_all_roles( $fragile_person,
+ 'IsFragile' );
- Does not change the
Person class
@@ -1727,7 +1771,7 @@ Person->new(); # kaboom
- Attributes can have defaults
- - Simple non-referecne scalars (number, string)
+ - Simple non-reference scalars (number, string)
- Subroutine reference
- A builder method
@@ -1768,7 +1812,7 @@ has bank => (
-
Default as a Subroutine Reference
+
Subroutine Reference Default
- Called as a method on the object
@@ -1841,7 +1885,8 @@ has bank => (
sub _build_bank {
my $self = shift;
- return Bank->new( name => 'Spire FCU' );
+ return Bank->new(
+ name => 'Spire FCU' );
}
-
Lazy, Good for Nothing Attributes
+
Lazy, Good for Nothin' Attributes
- Normally, defaults are generated during object construction
@@ -1914,7 +1959,7 @@ sub _build_shoes {
my $self = shift;
return Shoes->new(
- size => $_[0]->shoe_size );
+ size => $self->shoe_size );
}
@@ -2098,7 +2142,7 @@ use Moose;
has first_name => (
reader => 'get_first_name',
- writer => 'set_first_name,
+ writer => 'set_first_name',
);
@@ -2114,7 +2158,7 @@ has first_name => (
);
- - Can also mix-and-match
+ - Can also mix-and-match
is and explicit names
@@ -2165,7 +2209,8 @@ has first_name => (
Exercises
# cd exercises
-# perl bin/prove -lv t/03-basic-attributes.t
+# perl bin/prove -lv \
+ t/03-basic-attributes.t
Iterate til this passes all its tests
@@ -2234,7 +2279,8 @@ before work => sub {
my $self = shift;
return unless $DEBUG;
- warn "Called work on ", $self->full_name,
+ warn "Called work on ",
+ $self->full_name,
"with the arguments: [@_]\n";
};
@@ -2266,19 +2312,17 @@ after work => sub {
-
Other Uses Example
+
More Modifier Examples
has password => (
is => 'rw',
clearer => 'clear_password',
);
-
has hashed_password => (
is => 'ro',
builder => '_build_hashed_password',
clearer => '_clear_hashed_password',
);
-
after clear_password => sub {
my $self = shift;
$self->_clear_hashed_password;
@@ -2319,7 +2363,6 @@ after clear_password => sub {
$self->_munge_insert(@_) );
$new_user->_assign_uri;
-
return $new_user;
};
Modifier Order
- - Before runs order from last to first
+ - Before runs in order from last to first
- After runs in order from first to last
- Around runs in order from last to first
@@ -2397,13 +2440,13 @@ sub xml { '<doc>' . inner() . '</doc>
package Report;
extends 'Document';
-
-augment xml => { title() . inner() . summary() };
+augment xml =>
+ sub { title() . inner() . summary() };
package TPSReport;
extends 'Report';
-
-augment xml => { tps_xml() . inner() };
+augment xml =>
+ sub { tps_xml() . inner() };
@@ -2482,7 +2525,8 @@ extends 'Report';
Exercises
# cd exercises
-# perl bin/prove -lv t/04-method-modifiers.t
+# perl bin/prove -lv \
+ t/04-method-modifiers.t
Iterate til this passes all its tests
Part 5: Types
+
+
A Type System for Perl
+
+
+ - Sort of ...
+ - Variables are not typed
+ - Attributes can have types
+ - MooseX modules let you define method signatures
+
+
+
Components of a Moose Type
+
+
+ - A type is a name and a constraint
+ - Types have a hierarchy
+ - Constraints are cumulative from parents
+ - Types can have associated coercions
+
+
+
Built-in Type Hierarchy
+
+
+Any
+Item
+ Bool
+ Maybe[`a]
+ Undef
+ Defined
+ Value
+ Num
+ Int
+ Str
+ ClassName
+ RoleName
+
+
+
Built-in Type Hierarchy
+
+
+(Item)
+ (Defined)
+ (Value)
+ Ref
+ ScalarRef
+ ArrayRef[`a]
+ HashRef[`a]
+ CodeRef
+ RegexpRef
+ GlobRef
+ FileHandle
+ Object
+
+
+
Bool
+
+
True
+
1
+924.1
+'true'
+{}
+
+
False
+
0
+0.0
+'0'
+undef
+
+
+ - Like Perl's
if ($foo)
+
+
+
Value (and subtypes)
+
+
+ Value is true when ! ref $thingValue and Str are effectively the same, but Str is more expressive- An overloaded object which numifies does not pass the
Num constraint!
+ - Perl 5's overloading is hopelessly broken
+
+
+
ClassName and RoleName
+
+
+ - A string with a package name
+ - The package must already be loaded
+
+
+
Parameterizable Types
+
+
+ - What does
ArrayRef[`a] mean?
+ s/`a/Int/ (or Str or ...)- When you use it you can write ...
+
+ ArrayRef (== ArrayRef[Item])ArrayRef[Str]ArrayRef[MyTypeName]ArrayRef[HashRef[Maybe[Int]]]
+
+
+
+
Maybe[`a]
+
+
+ - Maybe means either the named type or
undef
+ Maybe[Int] accepts integers or undef
+
+
Type Union
+
+
+ - This or that (or that or ...)
+ Int | ArrayRef[Int]- But use a coercion instead when possible
+ - Or use a
role_type, duck_type, or anything not a union
+ - A union is often a code smell
+
+
+
Making Your Own Types
+
+
use Moose::Util::TypeConstraints;
+
+subtype 'PositiveInt',
+ as 'Int',
+ where { $_ > 0 },
+ message
+ { "The value you provided ($_)"
+ . " was not a positive int." };
+
+has size => (
+ is => 'ro',
+ isa => 'PositiveInt',
+);
+
+
Automatic Types
+
+
+ - Moose creates a type for every Moose class and role
+ - Unknown names are assumed to be classes
+
+
+
Automatic Types
+
+
package Employee;
+use Moose;
+
+has manager => (
+ is => 'rw',
+ isa => 'Employee',
+);
+
+has start_date => (
+ is => 'ro',
+ isa => 'DateTime',
+);
+
+
Subtype Shortcuts - class_type
+
+
use Moose::Util::TypeConstraints;
+class_type 'DateTime';
+
+subtype 'DateTime',
+ as 'Object',
+ where { $_->isa('DateTime') },
+ message { ... };
+
+
Subtype Shortcuts - role_type
+
+
use Moose::Util::TypeConstraints;
+role_type 'Printable';
+
+subtype 'Printable',
+ as 'Object',
+ where
+ { Moose::Util::does_role(
+ $_, 'Printable' ) },
+ message { ... };
+
+
Subtype Shortcuts - duck_type
+
+
use Moose::Util::TypeConstraints;
+duck_type Car => qw( run break_down );
+
+subtype 'Car',
+ as 'Object',
+ where { all { $_->can($_) }
+ qw( run break_down ) },
+ message { ... };
+
+
Subtype Shortcuts - enum
+
+
use Moose::Util::TypeConstraints;
+enum Color => qw( red blue green ) );
+
+my %ok = map { $_ => 1 }
+ qw( red blue green );
+
+subtype 'Color'
+ as 'Str',
+ where { $ok{$_} },
+ message { ... };
+
+
Anonymous Subtypes
+
+
package Person;
+
+my $posint =
+ subtype as 'Int', where { $_ > 0 };
+
+has size => (
+ is => 'ro',
+ isa => $posint,
+);
+
+
+ - Shortcuts have anonymous forms as well
+
+
+
Coercions
+
+
use Moose::Util::TypeConstraints;
+
+subtype 'UCStr',
+ as 'Str',
+ where { ! /[a-z]/ };
+
+
Coercions
+
+
coerce 'UCStr',
+ from 'Str',
+ via { uc };
+
+has shouty_name => (
+ is => 'ro',
+ isa => 'UCStr',
+ coerce => 1,
+);
+
+
Coercion Examples
+
+
subtype 'My::DateTime',
+ as class_type 'DateTime';
+
+coerce 'My::DateTime',
+ from 'HashRef',
+ via { DateTime->new( %{$_} ) };
+
+coerce 'My::DateTime',
+ from 'Int',
+ via { DateTime->from_epoch(
+ epoch => $_ ) };
+
+
+ - Use coercion to inflate a value
+
+
+
Coercion Examples
+
+
coerce 'ArrayRef[Int]',
+ from 'Int',
+ via { [ $_ ] };
+
+
+ - Instead of union -
Int | ArrayRef[Int]
+
+
+
Using Types with Attributes
+
+
package Person;
+
+has height => (
+ is => 'rw',
+ isa => 'Num',
+);
+
+has favorite_numbers => (
+ is => 'rw',
+ isa => 'ArrayRef[Int]',
+ coerce => 1,
+);
+
+
More Droppings
+
+
+ Moose::Util::TypeConstraints also needs cleanup
+
+
package Person;
+
+use Moose;
+use Moose::Util::TypeConstraints;
+
+subtype ...;
+
+no Moose;
+no Moose::Util::TypeConstraints;
+
+
Typed Methods (Low-tech)
+
+
package Person;
+use MooseX::Params::Validate qw( validated_list );
+
+sub work {
+ my $self = shift;
+ my ( $tasks, $can_rest ) =
+ validated_list(
+ \@_,
+ tasks =>
+ { isa => 'ArrayRef[Task]',
+ coerce => 1 },
+ can_rest =>
+ { isa => 'Bool',
+ default => 0 },
+ );
+ ...
+}
+
+
Typed Methods (High-tech)
+
+
package Person;
+
+use MooseX::Method::Signatures;
+
+method work ( ArrayRef[Task] :$tasks,
+ Bool :$can_rest = 0 ) {
+ my $self = shift;
+
+ ...
+}
+
+
Digression: The Type Registry
+
+
+ - Types are actually
Moose::Meta::TypeConstraints objects
+ - Stored in an interpreter-global registry mapping names to objects
+
+
+
Danger!
+
+
+ - Coercions are attached to type objects
+ - Therefore also global
+ - Name conflicts between modules!
+ - Coercion conflicts between modules!
+
+
+
Namespace Fix
+
+
+ - Use some sort of pseudo-namespacing scheme
+ - Never coerce directly to a class name, or to built-in types
+
+
+
Namespace Fix
+
+
use Moose::Util::TypeConstraints;
+subtype 'MyApp::Type::DateTime',
+ as 'DateTime';
+
+coerce 'MyApp::Type::DateTime',
+ from 'HashRef',
+ via { DateTime->new( %{$_} ) }
+
+has creation_date => (
+ is => 'ro',
+ isa => 'MyApp::Type::DateTime',
+ coerce => 1,
+);
+
+
Namespace Fix
+
+
subtype 'MyApp::Type::ArrayOfInt',
+ as 'ArrayRef[Int]';
+
+coerce 'MyApp::Type::ArrayOfInt',
+ from 'Int',
+ via { [ $_ ] };
+
+
Namespace Fix Pros and Cons
+
+
+ - Relatively simple
+ - Already built into Moose
+ - Conflates type and module namespaces
+ - Type names are strings, so typos are easy to make and may be hard to find
+
+
+
MooseX::Types
+
+
package MyApp::Types;
+
+use MooseX::Types
+ -declare => [ qw( ArrayOfInt ) ];
+use MooseX::Types::Moose
+ qw( ArrayRef Int );
+
+subtype ArrayOfInt,
+ as ArrayRef[Int];
+
+coerce ArrayOfInt
+ from Int,
+ via { [ $_ ] };
+
+
MooseX::Types
+
+
package MyApp::Account;
+
+use MyApp::Types qw( ArrayOfInt );
+
+has transaction_history => (
+ is => 'rw',
+ isa => ArrayOfInt,
+);
+
+
MooseX::Types
+
+
+ - Type names are exported functions, catches typos early
+ - Types must be pre-declared
+ - Types are stored with namespaces internally, but externally are short
+ - Import existing Moose types as functions from
MooseX::Types::Moose
+ - Still need string names for things like
ArrayRef['Email::Address']
+
+
+
MooseX::Types Pros and Cons
+
+
+ - Catches typos at compile time
+ - Automatic namespacing
+ - One more thing to install and learn
+ - Every name gets types 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
+
+
+
Recommendation
+
+
+ - Use
MooseX::Types
+ - Compile time error catching and automatic namespacing are huge wins
+ - Docs from
Moose::Util::TypeConstraints are 98% compatible with MooseX::Types anyway
+ - A function exported by a type library works wherever a type name would
+
+
+
Questions?
+
+
+
+
Exercises
+
+
# cd exercises
+# perl bin/prove -lv t/05-types.t
+
+Iterate til this passes all its tests
+
Part 6: Advanced Attributes
@@ -2554,7 +3129,8 @@ $alice->friend($bob);
use Moose;
has name => ( is => 'ro' );
-has friend => ( is => 'rw', weak_ref => 1 );
+has friend => ( is => 'rw',
+ weak_ref => 1 );
my $alice = Person->new( name => 'Alice' );
my $bob = Person->new( name => 'Bob' );
@@ -2673,7 +3249,6 @@ has lungs => (
package Person;
use Moose;
-
has account => (
is => 'ro',
isa => 'BankAccount',
@@ -2721,7 +3296,6 @@ has name => (
package Auditor;
use Moose::Role;
-
sub record_change { ... }
sub change_history { ... }
@@ -2749,6 +3323,112 @@ has history => (
+
Native Delegation
+
+
+ - Delegate to unblessed Perl types
+ - Scalar, array or hash ref, etc
+ - Treat Perl types as objects
+ - Still uses
handles
+ - Pretend that native Perl types have methods
+
+
+
Native Delegation - Array(Ref)
+
+
+ - Methods include:
+
+ pushshiftelements - returns all elementscountis_empty- quite a few more
+
+
+
+
+
+
+
Native Delegation - Array(Ref)
+
+
package Person;
+use Moose;
+has _favorite_numbers => (
+ traits => [ 'Array' ],
+ is => 'ro',
+ isa => 'ArrayRef[Int]',
+ default => sub { [] },
+ init_arg => undef,
+ handles =>
+ { favorite_numbers => 'elements',
+ add_favorite_number => 'push',
+ },
+);
+
+
+
+
Native Delegation - Array(Ref)
+
+
my $person = Person->new();
+
+$person->add_favorite_number(7);
+$person->add_favorite_number(42);
+
+print "$_\n"
+ for $person->favorite_numbers;
+
+# 7
+# 42
+
+
+
+
Native Delegation
+
+
+ - Native types are ...
+
+ - Number -
add, mul, ...
+ - String -
append, chop, ...
+ - Counter -
inc, dec, ...
+ - Bool -
set, toggle, ...
+ - Hash -
get, set, ...
+ - Array - already saw it
+ - Code -
execute, that's it
+
+
+
+
+
+
+
Curried Delegation
+
+
+ - A delegation with some preset arguments
+ - Works with object or Native delegation
+
+
+
+
+
Curried Delegation
+
+
package Person;
+use Moose;
+has account => (
+ is => 'ro',
+ isa => 'BankAccount',
+ handles => {
+ receive_100 =>
+ [ 'deposit', 100 ]
+ give_100 =>
+ [ 'withdraw', 100 ]
+ },
+);
+
+
+
Traits and Metaclasses
@@ -2791,7 +3471,6 @@ has ssn => (
isa => 'Str',
label => 'Social Security Number',
);
-
print Person->meta
->get_attribute('ssn')->label;
@@ -2810,7 +3489,6 @@ has ssn => (
isa => 'Str',
label => 'Social Security Number',
);
-
print
Person->meta
->get_attribute('ssn')->label;
@@ -2845,7 +3523,8 @@ print
Person->meta
Exercises
# cd exercises
-# perl bin/prove -lv t/06-advanced-attributes.t
+# perl bin/prove -lv \
+ t/06-advanced-attributes.t
Iterate til this passes all its tests
Part 9: Writing Moose Extensions
+
+
The End
+
+
+
+
+ 