Subscript Returns Error String as Value of AEXMLElement is Surprising (To Me) about aexml HOT 7 CLOSED

I kind of agree with @ivensdenner. My preferred usage is:

if let v = element["MyString"] {
    print(v.stringValue)
}

from aexml.

Hi all, thanks for this discussion.

In the latest version (3.0.0) I've improved error handling logic to be as you recommended here, that is:

• there is no errorElementName anymore
• subscript returns empty element (value = nil and stringValue = "")
• this empty element will have error property different then nil

Feel free to comment this change if you find anything suspicious (unit tests are passing but this can make breaking changes in other people code, that's why it's a major version bump).

This issue can be closed now.

from aexml.

Hmmm, I think I agree. :)
This will be left open for now, maybe I'll change that in some upcoming version.

from aexml.

What about the subscript returning an optional type? It sounds more natural to me.

from aexml.

No, that's what I wanted to avoid from the initial version. It's easier for end users when subscript is not an optional. And problem with empty string is that you couldn't differentiate when something really has no value or the complete element is missing.

from aexml.

Helped myself with:

extension AEXMLElement {
    var string: String? {
        if name == AEXMLElement.errorElementName { return nil }
        return stringValue
    }
}

from aexml.

In SwiftyJSON, there are two getters: string: String? and stringValue: String. The equivalent of SwiftyJSON's string: String? is AEXMLElement's value: String?, except that in SwiftyJSON if there's an error, string: String? will be nil instead of an error message. AEXMLElement can be made to mimic SwiftyJSON if subclassed like below:

class MyAEXMLElement: AEXMLElement {
    override var value: String? {
        get {
            guard name != AEXMLElement.errorElement else {
                return nil
            }
            return super.value
        }
        set {
            super.value = newValue
        }
    }

    override var stringValue: String {
        guard name != AEXMLElement.errorElement else {
            return ""
        }
        return super.stringValue
    }
}

And SwiftyJSON handles the errors by having an explicit error property, in case you want the actual error:

extension MyAEXMLElement {
    var error: String? {
        guard let value = value where name == AEXMLElement.errorElement else {
            return nil
        }
        return value
    }
}

Of course, I'm not saying the above is exactly how I think it should be implemented. I'm only showing how I would adapt the existing code to behave like SwiftyJSON.

from aexml.