objective c - NSTokenField with mixed token/string input, possible?

Question

When entering an invalid email in Mail's NSTokenField one get's this (a mix of token and plain string values):

Is there any recommendable way to accomplish this?
Is NSTokenField even the right tool for this? Or would I be abusing it?

In this particular project I need to allow the user to enter a file name pattern
(there are several other use cases though), with support for predefined tokens.

Right now I'm requiring the input to be entered like this:

Glue Text %[Tag]Other Glue Text%[Another Tag]More Text

I'd like to change this to some fool-proof graphical solution like this:

NSTokenField always(!) turns entered text into tokens.

Either I'm using the wrong keywords in my web searches,
or I'm really the first to need this (mixed) behaviour?!

I did read thru Apple's NSTokenField Guide, but couldn't find any info on my problem.

Answer 1

You need to implement the delegate method tokenField:styleForRepresentedObject: to return either NSRoundedTokenStyle for tokens or NSPlainTextTokenStyle for other text. The represented object for an token is the token string itself, unless your delegate returns other objects.

This should do the trick for your case:

- (NSTokenStyle)tokenField:(NSTokenField *)tokenField
 styleForRepresentedObject:(id)representedObject
{
    if ([representedObject rangeOfString: @"%["].location == 0) {
        return NSRoundedTokenStyle;
    } else {
        return NSPlainTextTokenStyle;
    }
}