perl - 如何在 Perl 中使用类属性/变量作为打印文件句柄？

Question

我想做同样的事情

open MYFILE, ">", "data.txt";
print MYFILE "Bob\n";

而是在类变量中

sub _init_tmp_db
{
    my ($self) = @_;

    open $$self{tmp_db_fh}, ">", "data.txt";
    print $$self{tmp_db_fh} "Bob\n";
}

它给了我这个错误:'在“Bob\n”附近找到运算符(operator)预期的字符串'

我该怎么办？

Answer 1

来自 print manpage :

If you're storing handles in an array or hash, or in general whenever you're using any expression more complex than a bareword handle or a plain, unsubscripted scalar variable to retrieve it, you will have to use a block returning the filehandle value instead.

你应该使用:

print { $$self{tmp_db_fh} } "Bob\n";

此代码在 use strict 下不起作用.要修复它，只需使用 my多变的:

open my $fh, ">", "data.txt" or die $!;
$$self{tmp_db_fh} = $fh;
print { $$self{tmp_db_fh} } "Bob\n";