Perl中的Tiescalar
我编写了以下模块作为将标量绑定到特定文件内容的模块:Perl中的Tiescalar,perl,Perl,我编写了以下模块作为将标量绑定到特定文件内容的模块: package Scalar; use strict; my $count = 0; use Carp; sub TIESCALAR{ print "Inside TIESCALAR function \n"; my $class = shift; my $filename = shift; if ( ! -e $filename ) { croak "Filename : $filename does not
package Scalar;
use strict;
my $count = 0;
use Carp;
sub TIESCALAR{
print "Inside TIESCALAR function \n";
my $class = shift;
my $filename = shift;
if ( ! -e $filename )
{
croak "Filename : $filename does not exist !";
}
else
{
if ( ! -r $filename || ! -w $filename )
{
croak "Filename : $filename is not readable or writable !";
}
}
$count++;
return \$filename , $class;
}
sub FETCH {
print "Inside FETCH function \n";
my $self = shift;
croak "I am not a class method" unless ref $self;
my $myfile = $$self;
open (FILE , "<$myfile") || die "Can't open the file for read operation $! \n";
flock(FILE,1) || die "Could not apply a shared lock $!";
my @contents = <FILE>;
close FILE;
}
sub STORE {
print "Inside STORE function \n";
my $self = shift;
my $value = shift;
croak "I am not a class method" unless ref $self;
my $myfile = $$self;
open (FILE , ">>$myfile") or die "Can't open the file for write operation $! \n";
flock(FILE,2);
print FILE $value;
close FILE;
}
1;
当我尝试运行此代码时,出现以下消息:
Inside TIESCALAR function
Trying to retrieve file contents
Trying to add a line to file
Reading contents again
Can't use string ("This is a test line added") as an ARRAY ref while "strict refs" in use at Scalar.pl line 21.
我认为代码不会进入模块的FETCH和STORE函数中。有人能指出这是什么问题吗?我认为你的问题的根源在于你实际上没有祝福你的价值观 参考一个例子: 我认为您需要将
TIESCALAR
的最后一行更改为:
return bless \$filename, $class;
否则,它所做的只是“返回”文件名,而不是绑定它
我不能完全重现您的问题-但我认为您在隐式返回FETCH
时也会遇到问题,它实际上不会返回@内容
,而是返回close
的返回代码
我还建议-3参数
open
是好的,尤其是当您执行类似操作时,因为否则FILE
是一个全局变量,可能会被删除 我在获取代码中添加了这一行:return(\@contents);结果仍然是一样的。每次代码进入获取或存储例程时,我希望它至少打印打印语句。它也没有这样做。
return bless \$filename, $class;