我应该如何将对象传递给子程序? [英] How should I pass objects to subroutines?

问题描述

其中一种是最好的还是最差的方法?

Is one of these the best or the worst approach?

利用范围:

my $cache = CHI->new( driver => 'File', expires_in => 3600 );

sub one {
    if ( my $data = $cache->get( 'key_one' ) ) {
    # ...
}

sub two {
    if ( my $data = $cache->get( 'key_two' ) ) {
    # ...
}

将对象作为参数传递:

my $cache = CHI->new( driver => 'File', expires_in => 3600 );

sub one {
    my ( $cache ) = @_;
    if ( my $data = $cache->get( 'key_one' ) ) {
    # ...
}

sub two {
    my ( $argument1, $cache ) = @_;
    if ( my $data = $cache->get( 'key_two' ) ) {
    # ...
}

或在子程序中创建一个新实例:

or creating in the subroutine a new instance:

sub one {
    my $cache = CHI->new( driver => 'File', expires_in => 3600 );
    if ( my $data = $cache->get( 'key_one' ) ) {
    # ...
}

sub two {
    my $cache = CHI->new( driver => 'File', expires_in => 3600 );
    if ( my $data = $cache->get( 'key_two' ) ) {
    # ...
}

推荐答案

首选使用全局变量，没那么热.第三个选择是很多额外的开销.也不是很好，所以我想在你的问题的背景下，中间的选择更可取.一个更广泛的问题是为什么子程序根本需要知道缓存?看来他们只担心数据.我会考虑获取数据并将其传递给子程序，在那里他们不必担心它是被缓存还是刚刚创建.

First choice uses a global variable, not so hot. Third choice is a lot of extra overhead. Not so great either, so I guess the middle choice is preferable within the context of your question. A broader issue is why do the subroutines need to know about the cache at all? It appears they are only worried about the data. I would consider fetching the data and pass that to the subroutines, where they don't have to worry if it was cached or just created.

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