Elvis operator not working on application scope or session

dev support
1

I am finding that the Elvis operator does not work against session or application scopes.

url.errorCode = url.errorCode ?: 200;

This works but

application.flip = !application.flip ?: false;

Does not. I have to add

    if (not isDefined("application.flip")) {

        application.flip = false;   

    }

I have tried it locally under command box with latest Lucee 5 and on server under IIS and various versions of Lucee 5 all with same results.

Is this a known issue / intended outcome?

2

Wrap the Application part in some paranthesis…

// This doesn't work
application.flip = !application.flip ?: false;

// This does
application.flip = !(application.flip ?: false);
1 Like
3

Cheers that worked, should it be reported as a bug so it gets fixed long term?

4

I’m not exactly sure what you are trying to do?

As both of them will error out if the key doesn’t exist or if the value is a string (with the exclamation mark included):

url.errorCode = !url.errorCode ?: 200; // key [ERRORCODE] doesn't exist

session.flip = !session.flip ?: false; // key [FLIP] doesn't exist

session.flip = !'text' ?: false; // Can't cast String [text] to a boolean

My assumption is that you try to set a value if it doesn’t exist.

One way could be with cfparam (https://docs.lucee.org/reference/tags/param.html)
Another one would be to use a ternary (Operators :: Lucee Documentation):

session.flip = session.keyExists('flip') ? session.flip : false;

session.flip = !isNull(session.flip) ? session.flip : false;

session.flip = session.keyExists('flip') && isBoolean(session.flip) ? session.flip : false;

I believe here it would need to have two exclamation marks, otherwise it might be a toggle, then again maybe this was the point / what the person wanted.

dump(session.keyExists('flip') ? session.delete('flip') & ' flip deleted' : 'flip not exist');
dump(var=session.flip = !(session.flip ?: false)); // true
dump(var=session.flip = !(session.flip ?: false)); // false
dump(var=session.flip = !(session.flip ?: false)); // true

dump(session.keyExists('flip') ? session.delete('flip') & ' flip deleted' : 'flip not exist');
dump(var=session.flip = !!(session.flip ?: false)); // false
dump(var=session.flip = !!(session.flip ?: false)); // false
dump(var=session.flip = !!(session.flip ?: false)); // false