package BankAccount;
use Moose;
-
- has 'balance' => (isa => 'Int', is => 'rw', default => 0);
-
+
+ has 'balance' => ( isa => 'Int', is => 'rw', default => 0 );
+
sub deposit {
- my ($self, $amount) = @_;
- $self->balance($self->balance + $amount);
+ my ( $self, $amount ) = @_;
+ $self->balance( $self->balance + $amount );
}
-
+
sub withdraw {
- my ($self, $amount) = @_;
+ my ( $self, $amount ) = @_;
my $current_balance = $self->balance();
- ($current_balance >= $amount)
+ ( $current_balance >= $amount )
|| confess "Account overdrawn";
- $self->balance($current_balance - $amount);
+ $self->balance( $current_balance - $amount );
}
-
+
package CheckingAccount;
use Moose;
-
+
extends 'BankAccount';
-
- has 'overdraft_account' => (isa => 'BankAccount', is => 'rw');
-
+
+ has 'overdraft_account' => ( isa => 'BankAccount', is => 'rw' );
+
before 'withdraw' => sub {
- my ($self, $amount) = @_;
+ my ( $self, $amount ) = @_;
my $overdraft_amount = $amount - $self->balance();
- if ($self->overdraft_account && $overdraft_amount > 0) {
+ if ( $self->overdraft_account && $overdraft_amount > 0 ) {
$self->overdraft_account->withdraw($overdraft_amount);
$self->deposit($overdraft_amount);
}
The first class, B<BankAccount>, introduces a new attribute feature, a
default value:
- has 'balance' => (isa => 'Int', is => 'rw', default => 0);
+ has 'balance' => ( isa => 'Int', is => 'rw', default => 0 );
This says that a B<BankAccount> has a C<balance> attribute, which has
a C<Int> type constraint, a read/write accessor, and a default value
B<BankAccount>. The next line introduces yet another new attribute
feature, class-based type constraints:
- has 'overdraft_account' => (isa => 'BankAccount', is => 'rw');
+ has 'overdraft_account' => ( isa => 'BankAccount', is => 'rw' );
Up until now, we have only seen the C<Int> type constraint, which (as
we saw in the first recipe) is a builtin type constraint. The
modifier.
before 'withdraw' => sub {
- my ($self, $amount) = @_;
+ my ( $self, $amount ) = @_;
my $overdraft_amount = $amount - $self->balance();
- if ($self->overdraft_account && $overdraft_amount > 0) {
+ if ( $self->overdraft_account && $overdraft_amount > 0 ) {
$self->overdraft_account->withdraw($overdraft_amount);
$self->deposit($overdraft_amount);
}
C<SUPER::> to get the same effect:
sub withdraw {
- my ($self, $amount) = @_;
+ my ( $self, $amount ) = @_;
my $overdraft_amount = $amount - $self->balance();
- if ($self->overdraft_account && $overdraft_amount > 0) {
+ if ( $self->overdraft_account && $overdraft_amount > 0 ) {
$self->overdraft_account->withdraw($overdraft_amount);
$self->deposit($overdraft_amount);
}