我应该如何传递对象的子程序？ [英] How should I pass objects to subroutines?

问题描述

是其中最好的一个或最坏的做法？

使用范围：

 我的$ =缓存智＆gt;新建（驱动程序= GT;文件，expires_in =＆GT; 3600）;子有一个{
    如果（我的$数据= $＆的cache GT;获取（'key_one'））{
    ＃...
}的亚二{
    如果（我的$数据= $＆的cache GT;获取（'key_two'））{
    ＃...
}
 

传递对象作为参数：

 我的$ =缓存智＆gt;新建（驱动程序= GT;文件，expires_in =＆GT; 3600）;子有一个{
    我（$缓存）= @_;
    如果（我的$数据= $＆的cache GT;获取（'key_one'））{
    ＃...
}的亚二{
    我（$参数1，$缓存）= @_;
    如果（我的$数据= $＆的cache GT;获取（'key_two'））{
    ＃...
}
 

或在子程序创建一个新的实例

 子有一个{
    我的$ =缓存智＆gt;新建（驱动程序= GT;文件，expires_in =＆GT; 3600）;
    如果（我的$数据= $＆的cache GT;获取（'key_one'））{
    ＃...
}的亚二{
    我的$ =缓存智＆gt;新建（驱动程序= GT;文件，expires_in =＆GT; 3600）;
    如果（我的$数据= $＆的cache GT;获取（'key_two'））{
    ＃...
}
 

解决方案

第一选择使用一个全局变量，没有这么热。第三个选择是很多额外的开销。没有那么大任，所以我想中间的选择是你的问题的范围内preferable。一个更广泛的问题是，为什么子程序需要了解缓存呢？看样子他们只担心数据。我会考虑获取数据并传递给子程序，他们不必担心，如果它被缓存或刚创建。

Is one of these the best or the worst approach?

utilize the scope:

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' ) ) {
    # ...
}

passing the object as argument:

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' ) ) {
    # ...
}

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' ) ) {
    # ...
}

解决方案

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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