Perl尝试捕获用户定义的异常

发布时间：2020-12-16 06:21:33 所属栏目：大数据来源：网络整理

导读：我想知道perl是否有一些类似于 python的try catch机制,我可以提高用户定义的异常并相应地处理. Python代码： try: number = 6 i_num = 3 if i_num number: raise ValueTooSmallError elif i_num number: raise ValueTooLargeError break except ValueTooSmal

我想知道perl是否有一些类似于 python的try catch机制,我可以提高用户定义的异常并相应地处理.

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尝试抓住机制,如下所示：

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

要么

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
  }

我更专注于对捕获的if检查.有没有办法可以避免检查我遇到的不同类型的错误.

解决方法

最接近的解决方案可能是直接的 failures对象,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,});
    }
} 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.

（编辑：李大同）

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