我在解决一个对象和一个类之间的概念差异时遇到了一些麻烦.我真的不明白两者在任何编程语言中的区别,但目前我正在使用Perl和Moose,所以我更喜欢使用这些东西进行解释.
干杯
解决方法
有很多“一个类是一个蓝图,一个对象是从该蓝图构建的东西”,但是既然你已经要求使用Moose和Perl的一个具体例子,我想我会提供一个.
在下面的示例中,我们将有一个名为“Hacker”的类.该类(如蓝图)描述了黑客是什么(他们的属性)以及他们可以做什么(他们的方法)：
package Hacker; # Perl 5 spells 'class' as 'package'
use Moose; # Also enables strict and warnings;
# Attributes in Moose are declared with 'has'. So a hacker
# 'has' a given_name,a surname,a login name (which they can't change)
# and a list of languages they know.
has 'given_name' => (is => 'rw',isa => 'Str');
has 'surname' => (is => 'rw',isa => 'Str');
has 'login' => (is => 'ro',isa => 'Str');
has 'languages' => (is => 'rw',isa => 'ArrayRef[Str]');
# Methods are what a hacker can *do*,and are declared in basic Moose
# with subroutine declarations.
# As a simple method,hackers can return their full name when asked.
sub full_name {
my ($self) = @_; # $self is my specific hacker.
# Attributes in Moose are automatically given 'accessor' methods,so
# it's easy to query what they are for a specific ($self) hacker.
return join(" ",$self->given_name,$self->surname);
}
# Hackers can also say hello.
sub say_hello {
my ($self) = @_;
print "Hello,my name is ",$self->full_name,"\n";
return;
}
# Hackers can say which languages they like best.
sub praise_languages {
my ($self) = @_;
my $languages = $self->languages;
print "I enjoy programming in: @$languages\n";
return;
}
1; # Perl likes files to end in a true value for historical reasons.
现在我们已经获得了Hacker类,我们可以开始制作Hacker对象了：
#!/usr/bin/perl
use strict;
use warnings;
use autodie;
use Hacker; # Assuming the above is in Hacker.pm
# $pjf is a Hacker object
my $pjf = Hacker->new(
given_name => "Paul",surname => "Fenwick",login => "pjf",languages => [ qw( Perl C JavaScript) ],);
# So is $jarich
my $jarich = Hacker->new(
given_name => "Jacinta",surname => "Richardson",login => "jarich",languages => [ qw( Perl C Haskell ) ],);
# $pjf can introduce themselves.
$pjf->say_hello;
$pjf->praise_languages;
print "\n----\n\n";
# So can $jarich
$jarich->say_hello;
$jarich->praise_languages;
这导致以下输出：
Hello,my name is Paul Fenwick I enjoy programming in: Perl C JavaScript ---- Hello,my name is Jacinta Richardson I enjoy programming in: Perl C Haskell
如果我想要我可以拥有尽可能多的Hacker对象,但仍然只有一个Hacker类描述了所有这些对象的工作原理.
祝一切顺利,
保罗