perl 裸块

裸块的特点：裸块内用my声明的变量只在裸块内有效

Eg:

my $a = 10;

sub fun{

         printf "%s\n",$a;

    }

fun(); ##10

{

my $a =20;

sub naked_fun{

         printf "%s\n",$a;

}

naked_fun();  #20

fun(); #10

}

naked_fun();  #20

fun(); #10

但是对没有用my声明的变量，没有这个效果

Eg:

my $a = 10;

sub fun{

         printf "%s\n",$a;

    }

fun(); ##10

{

$a =20;   #和正常的改值语句相同

sub naked_fun{

         printf "%s\n",$a;

}

naked_fun();  #20

fun(); #20

}

naked_fun();  #20

fun(); #20