如何在Perl中调用名称为哈希值的子例程？

Question

$ cat test.pl
use strict;
use warnings;

sub route {
    print "hello, world!";
}

my %h;
$h{'a'} = 'route';

print "1\n";
$h{a};

print "2\n";
$h{a}();

print "3\n";
"$h{a}".();
$ perl test.pl
Useless use of hash element in void context at test.pl line 12.
Useless use of concatenation (.) or string in void context at test.pl line 18.
1
2
Can't use string ("route") as a subroutine ref while "strict refs" in use at test.pl line 15.
$

什么是正确的打电话方式route()？

Answer 1

您正尝试使用$ h {a}作为符号引用.并且"使用严格"明确禁止这一点.如果你关闭严格模式,那么你可以这样做:

no strict;
&{$h{a}};

但最好的方法是在哈希中存储子程序的"实际"引用.

#!/usr/bin/perl

use strict;
use warnings;

sub route {
    print "hello, world!";
}

my %h;
$h{a} = \&route;

$h{a}->();