Re: some questions on PEAR_Error usage

On 4/24/2001 08:31 PM, Stig Sæther Bakken wrote:

[Steven Haryanto <steven@haryan.to>] I am developing a coding standard for our projects and I have several questions on the usage of PEAR_Error. 1. Should I create my own "exception" type subclassing from

    PEAR_Error. I know that PEAR_Error is somehow the current
    PHP's way of exception handling. But since there is no
    real exception ('try {...} except(ExcClass)') is it worth
    it to create my own ExcClass? And moreover, I can stuff
    whatever additional info on PEAR_Error's $message, $code,
    $options, $userinfo.

Normally you won't need to subclass PEAR_Error. The cases I can think of is where you only want the concept of an error code (like in DB), or if you want to report a lot of extra information.

Ok, thanks.

You can put whatever you want into $message, $code and $userinfo. $mode and $options are owned by the API though. 2. I want to set so that errors raised will print the error

    message complete with the originating object, the user info,
    etc. Any advice on how should I do this?

3. Should I just always use 'return $this->raiseError(...)'

    instead of 'return new PEAR_Error(...)' if my method
    want to report error?

Yes. The reason is that $this->raiseError() is the one that gives the "end user" the most error handling flexibility. It's not an absolute though, if you're making classes for your own use and you don't want to subclass PEAR, "return new PEAR_Error()" is ok.

Of course, now I understand. "return new PEAR_Error()" also works for non-PEAR classes.

How do you guys find this style:

    function method() {
        if ($foo) {   // error!
             $this->error = $this->raiseError();
             return 0;   // false
        }
        return 1;
    }

    ...

    if (!$obj->method()) {
        // handle the error
    }

over the current convention:

    function method() {
        if ($foo) {   // error!
             return $this->raiseError();
        }
        return;
    }

    ...

    $res = $obj->method();
    if (PEAR::isError($res)) {
        // handle the error
    }

(That is, the reporting method just returns 1/0 status so that checking error syntax is simplified). The actual PEAR_Error instance is available in $obj->error. The current convention works for functions and objects/methods. Your alternative style only works for objects.

Yeah. It's just that '(if PEAR::isError($res))' feels too verbose for me. And moreover, I hope this whole exception "simulation" thing is a temporary solution until PHP truly supports extension in the future. Thanks, Steve