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I'm trying to adapt the pop-up menu from the "One with Everything" demo in such a way that a given command will appear in the menu only once, until it's used. I can't see how to do this. Here's what I tried:

However, setting the upper item to classes: 'once' has no effect. The command is still in the menu after being used, and can be used again. Obviously, I don't want the make the whole link 'once', because it will ultimately contain four or five commands. I just want 'once' to apply to individual commands within it.

This code is declarative rather than procedural, so there's no obvious way to insert an if-test. I could possibly insert an if-test at the very start of the enter function, but that would mean duplicating the entire system.write block 2-to-the-(n-minus-1) times, where n is the number of menu items that may need to be shut off. That type of thing would be hideous to maintain, so there just has to be an easier solution. But I'm nowhere near familiar enough with Javascript, CSS, or the Vorple library to see how to do it.

Suggestions would be much appreciated!

The easy solution is to use disposable links instead of once links. Once-links clear from the screen only at the time they're clicked, and since the popups are hidden anyway there's no actual effect.

The downside is that with disposable links the choice is not removed from the popup, it's just not clickable anymore. If you want the entire choice removed, you need to build the list of choices dynamically.

Initialize a flag in undum.game.init():


The situation:


In the lookatjulia action toggle the flag and remove the choice:



The anonymous function in vorple.html.link builds the choice set dynamically based on whatever logic you put there every time the reader enters the situation. The last line in the lookatjulia action removes the choice in the current popup, otherwise the choice would not be disabled until after the reader enters the same situation again. (Note that the "don't use SimpleSituation with a string argument" caveat applies.)

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Thanks, Juhana. That all makes sense to me, except for the final line of code, the one starting with $. I sort of get that that causes the script to "forget" the return value of the anonymous function, so it runs again the next time the menu is used. But the actual syntax, and the reasons why it works, are shrouded in veils of mystery....

I think it's probably time for me to start studying Javascript seriously. There's a lot that can be done with it -- basically, anything. But it's very much a DIY situation, so it would be wrong for me to keep pestering you for solutions to one-off problems.

BTW, Ian Millington tells me he's not planning to add a more robust game-saving functionality to Undum unless/until he gets more requests. There's another reason why I need to become proficient in Javascript! Customizing Undum should ultimately be easier than customizing the behavior of TADS, because the TADS compiler and virtual machine are black boxes. (To me, at least -- the source code is available.) But the path to mastery of the "normal" functionality of Undum is not easy at all.

Actually the last line just removes one option from the popup and leaves the rest there, the anonymous function isn't affected at all. The $ is a jQuery object which is mostly used to manipulate HTML document elements. Normally you wouldn't need it but this case is more of a hack. (I'll think about adding the functionality to Vorple.)

Now that I think about it the last line is all you need, provided that the reader can never return to that same situation again. All the rest is just for making sure the popup is built correctly when entering the situation more than once. The anonymous function trick is still useful to know, it comes in handy in many cases.

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Vorple UI library — Beta testing site — Blog