符号表:删除条目 [英] Symbol-table: deleting entries

问题描述

为什么在删除了相应的符号表条目之后从"$ n"和"$ m"中获取值?

Why do I get the values from "$n" and "$m" after deleting the respective symbol-table-entries?

#!/usr/bin/env perl
use warnings;
use 5.012;

package Foo;

our $n = 10;
our $m = 20;

delete $Foo::{'n'};
delete $Foo::{'m'};

say $n; # 10
say $m; # 20

推荐答案

因为符号表仅在编译时使用(或通过符号引用使用). $Foo::{...}值的glob由编译后的代码直接引用，因此不再存在的符号表条目无效.

Because the symbol table is only used at compile time (or via symbolic reference). The glob that is the value of $Foo::{...} is referenced directly by the compiled code so the no-longer-present symbol table entry has no effect.

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