perl - 在 "foreach"循环中会发生什么样的定位？

Question

来自 perldoc perlsyn关于 Foreach 循环的主题:

If the variable was previously declared with my, it uses that variable instead of the global one, but it's still localized to the loop.

但是考虑这个例子:

use Devel::Peek;
my $x = 1;
Dump $x;
for $x ( 1 ) { Dump $x }

SV = IV(0x8117990) at 0x8100bd4
  REFCNT = 1
  FLAGS = (PADBUSY,PADMY,IOK,pIOK)
  IV = 1
SV = IV(0x8117988) at 0x8100bf8
  REFCNT = 2
  FLAGS = (IOK,READONLY,pIOK)
  IV = 1

似乎这些不是相同的变量。这是文档中的错误，还是我遗漏了什么？

Answer 1

每条规则都需要异常(exception)，这就是异常(exception)。在 for 循环中，如果循环变量是词法变量(用 my 声明)，Perl 将创建一个新词法，别名为循环中的当前项。 OP代码可以写成如下:

use Data::Alias 'alias';

my $x = 1;
for (2..3) {
    alias my $x = $_;
    # note that $x does not have dynamic scope, and will not be visible in 
    # subs called from within the loop
    # but since $x is a lexical, it can be closed over
}

编辑:前面的例子是 Perl 伪代码，为清楚起见修改了答案。