perldoc对我们的。

与我的方法不同，我的方法既为变量分配存储空间，又将一个简单的名称与该存储空间关联起来，以便在当前作用域内使用，而我们的方法则将一个简单的名称与当前包中的一个包变量关联起来，以便在当前作用域内使用。换句话说，our具有与my相同的作用域规则，但不一定创建变量。

让我们思考一下解释器到底是什么:它是一段在内存中存储值的代码，并让它所解释的程序中的指令通过指令中指定的名称访问这些值。因此，解释器的主要工作是制定规则，规定我们应该如何在这些指令中使用名称来访问解释器存储的值。

在遇到“my”时，解释器创建一个词法变量:解释器只能在执行块时访问一个命名值，而且只能从该语法块中访问。在遇到“our”时，解释器会为包变量创建一个词法别名:它将一个名称绑定到具有相同名称的包变量的值上，从那时起解释器就应该将其作为词法变量的名称处理，直到块完成。

The effect is that you can then pretend that you're using a lexical variable and bypass the rules of 'use strict' on full qualification of package variables. Since the interpreter automatically creates package variables when they are first used, the side effect of using "our" may also be that the interpreter creates a package variable as well. In this case, two things are created: a package variable, which the interpreter can access from everywhere, provided it's properly designated as requested by 'use strict' (prepended with the name of its package and two colons), and its lexical alias.

来源:

http://perldoc.perl.org/functions/our.html http://perldoc.perl.org/perlsub.html Private-Variables-via-my ()

一个例子:

use strict;

for (1 .. 2){
    # Both variables are lexically scoped to the block.
    our ($o);  # Belongs to 'main' package.
    my  ($m);  # Does not belong to a package.

    # The variables differ with respect to newness.
    $o ++;
    $m ++;
    print __PACKAGE__, " >> o=$o m=$m\n";  # $m is always 1.

    # The package has changed, but we still have direct,
    # unqualified access to both variables, because the
    # lexical scope has not changed.
    package Fubb;
    print __PACKAGE__, " >> o=$o m=$m\n";
}

# The our() and my() variables differ with respect to privacy.
# We can still access the variable declared with our(), provided
# that we fully qualify its name, but the variable declared
# with my() is unavailable.
print __PACKAGE__, " >> main::o=$main::o\n";  # 2
print __PACKAGE__, " >> main::m=$main::m\n";  # Undefined.

# Attempts to access the variables directly won't compile.
# print __PACKAGE__, " >> o=$o\n";
# print __PACKAGE__, " >> m=$m\n";

# Variables declared with use vars() are like those declared
# with our(): belong to a package; not private; and not new.
# However, their scoping is package-based rather than lexical.
for (1 .. 9){
    use vars qw($uv);
    $uv ++;
}

# Even though we are outside the lexical scope where the
# use vars() variable was declared, we have direct access
# because the package has not changed.
print __PACKAGE__, " >> uv=$uv\n";

# And we can access it from another package.
package Bubb;
print __PACKAGE__, " >> main::uv=$main::uv\n";

这只是与问题有点相关，但我刚刚发现了一个(对我来说)模糊的perl语法，你可以使用“我们的”(包)变量，而不能使用“我的”(本地)变量。

#!/usr/bin/perl

our $foo = "BAR";

print $foo . "\n";
${"foo"} = "BAZ";
print $foo . "\n";

输出:

BAR
BAZ

如果你把“our”改成“my”，这就行不通了。

perldoc对我们的。

与我的方法不同，我的方法既为变量分配存储空间，又将一个简单的名称与该存储空间关联起来，以便在当前作用域内使用，而我们的方法则将一个简单的名称与当前包中的一个包变量关联起来，以便在当前作用域内使用。换句话说，our具有与my相同的作用域规则，但不一定创建变量。

处理作用域是对Perl作用域规则的一个很好的概述。它已经足够古老了，所以我们没有在正文中讨论。在最后的Notes一节中讨论了这个问题。

本文讨论包变量和动态作用域，以及它们与词法变量和词法作用域的区别。