perl - 什么是 @。在 Perl 中？

Question

perl 中的@. 变量是什么？

它似乎是一个特殊的、可写的全局变量，并且(令人惊讶地)不会插入双引号字符串中:

use strict;
use warnings;

                 # Under 5.8, 5.10, 5.12, 5.14, and 5.16,
                 # the following lines produce:

@. = (3, 2, 1);  # no error
print "@.\n";    # "@."
print @., "\n";  # "321"

eval 'my @.; 1'  # Can't use global @. in "my" at (eval 1)
  or die $@;     #  line 1, near "my @."

我不记得以前遇到过它，并且在 perlvar 和 perldata 中都没有看到它。

Answer 1

perldoc perlvar状态:

Perl variable names may also be a sequence of digits or a single punctuation or control character. These names are all reserved for special uses by Perl;

和

Perl identifiers that begin with digits, control characters, or punctuation characters are exempt from the effects of the package declaration and are always forced to be in package main; they are also exempt from strict 'vars' errors.

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