Perl try catch 用户定义的异常

Question

我想知道 perl 是否有一些类似于 python 的 try catch 机制，我可以在其中引发用户定义的异常并进行相应的处理。

Python代码:

   try:
       number = 6
       i_num = 3
       if i_num < number:
           raise ValueTooSmallError
       elif i_num > number:
           raise ValueTooLargeError
       break
   except ValueTooSmallError:
       print("This value is too small, try again!")
       print()
   except ValueTooLargeError:
       print("This value is too large, try again!")
       print()

我知道 perl 有像下面这样的 try catch 机制:

sub method_one {
    try {
        if ("number" eq "one") {
            die("one");
        } else {
            die("two");
        }
    } catch {
        if ($@ eq "one") {
            print "Failed at one";
        }
    }
}

或者

eval {
    open(FILE, $file) || 
      die MyFileException->new("Unable to open file - $file");
  };

  if ($@) {
    # now $@ contains the exception object of type MyFileException
    print $@->getErrorMessage();  
    # where getErrorMessage() is a method in MyFileException class
  }

我更专注于 如果 检查渔获量。有没有办法可以避免检查我发现的不同类型的错误。

Answer 1

最接近的解决方案可能是直截了当的 failures对象和 TryCatch用于类型检查。

use failures qw(
    Example::Value_too_small
    Example::Value_too_large
);
use TryCatch;

try {
    my $number = 6;
    my $i_num = 3;
    if ($i_num < $number) {
        failure::Example::Value_too_small->throw({
            msg => '%d is too small, try again!',
            payload => $i_num,
        });
    } elsif ($i_num > $number) {
        failure::Example::Value_too_large->throw({
            msg => '%d is too large, try again!',
            payload => $i_num,
        });
    }
} catch (failure::Example::Value_too_small $e) {
    say sprintf $e->msg, $e->payload;
} catch (failure::Example::Value_too_large $e) {
    say sprintf $e->msg, $e->payload;
} finally {
    ...
}

您可以从这里升级到 custom::failures , Throwable , Exception::Class .