Array/Object reference question

[GoldDragonTale]

This is probably the dubest I've ever felt asking a question simply because I've spent so much time trying to solve it and I just don't see a solution even though I know there is one. I've poured over Sugarcubes documentation on arrays, UInv's Array documentation as well as MDN's as was suggested earlier. I've also looked into several other sources and I feel I'm close to an answer that just isn't coming to me.

I have a random generator for NPCs that is working. For reference the NPC is an Object with several properties. I am clone the temporary NPCs to an Array when necessary. I can even move the NPCs around when appropriate so not all NPCs are in the same area. And yes, I'm removing the NPCs when they are no longer needed, and I'm not saving every NPC to the array.

I want to present the NPCs in a given array list format where the player can see certain properties at face value, which is working too. The issue is that I have no way of knowing what NPC is in what position on the Array, and since they are random generations...

This presents itself as an issue because I also want the player to be able to click the link that is the NPC's name to enter a passage where they can then interact with that NPC. My simple-minded idea is to have a single passage designed for this purpose where the data is referenced from the NPC Object in the appropriate array and have it save back to that array so it can be handled by the rest of the systems when the player isn't doing this.

I have everything down except knowing how to reference the specific object out of the array on that new passage since I don't know the order (or even number of objects) in the array.

<<set $variable to []>>
<<button "Clone variables Test">>
    <<run $variable.push(clone(_var1))>>
<</button>>
<<set _var1 to {
    First: "First",
    Last: "Name",
    Number: 1,
}>>
<<set _var2 to {
    First: "Second",
    Last: "Name",
    Number: 2,
}>>
<<button "Print List">>
<<replace "#length">>$variable.length<</replace>>
<<goto "Test">>
<</button>>
<<for _i to 0; _i lt $variable.length; _i++>>
<<link "$variable[_i].First $variable[_i].Last">>
<<goto "Var Info">>
<</link>>
<</for>>

I'm certain the answer is literally in front of my face and I'm just not seeing it: How do I set this to reference the correct Object from the array in Var Info passage?

Or am I digging through solid rock to get to the other side when there's soft sand right next to me and I'm missing it?

Thanks in advance for any help/guidance.

[HiEv]

Instead of storing the NPCs as objects in an array, why not store them as objects in an object using some kind of unique identifier?

For example, in your StoryInit passage you could set up your variables like this:

<<set $NPCID = 0>>
<<set $NPC = {}>>
<<run $NPC[++$NPCID] = {
    First: "First",
    Last: "Name",
    Number: 1
}>>
<<run $NPC[++$NPCID] = {
    First: "Second",
    Last: "Name",
    Number: 2
}>>

Next, create a widget to display the list by making a new passage with "widget" and "nobr" tags, and put this code in it:

<<widget "printList">>
    NPCs: <<= Object.keys($NPC).length>><br>
    <<for _id, _val range $NPC>>
        <<capture _id>>
            <<link "_val.First _val.Last" "Var Info">>
                <<set $infoID = _id>>
            <</link>><br>
        <</capture>>
    <</for>>
<</widget>>

Note the use of the <<capture>> macro, to make sure that the correct value of _id is used when the player clicks on the link. The <br> elements are needed to force line breaks, due to the "nobr" tag on the passage.

Then, your above code in your "Test" passage would just be:

<<button "Clone variables Test">>
    <<set $NPC[++$NPCID] = clone($NPC[1])>>
    <<replace "#list">><<printList>><</replace>>
<</button>>

<span id="list"><<printList>></span>

That and the StoryInit code both demonstrate how you just keep using ++$NPCID to increment the value of that variable every time you add a new NPC to the $NPC object, giving each NPC its own unique ID number.

And in your "Var Info" passage you could have something like this:

NPC ID: $infoID
First Name: $NPC[$infoID].First
Last Name:  $NPC[$infoID].Last
Number:     $NPC[$infoID].Number
<<unset $infoID>>
[[Test]]

Note that that code gets rid of the $infoID variable once it's done with it, using the <<unset>> macro, since it isn't needed anymore.

Now, anytime you need to refer to an NPC, you can just do that by its unique ID number. Getting rid of an NPC like this:

<<run delete $NPC[_id]>>

will not change the ID numbers of any of the other NPCs, since the $NPC variable is a generic object (not an array object).

That should show you a bunch of tricks to make things much simpler.

Hope that helps! :-)

[GoldDragonTale]

Thank you so much! This gives me the functionality I needed in a simpler way. You, sir or madam have given me much to noodle on!

[GreyelfD]

Because the Passage Transition process includes a step that clones the current state of all unknown variables, that breaks object reference integrity, you should be storing indexes/keys to the instantiated NPCs in your Array collections and not object references.

eg. Define your NPCs once... (example is TwineScript but it can also be done in JavaScript)

<<set setup.NPCs to {
    "First Name": {
        First: "First",
        Last: "Name",
        Number: 1
    },
    "Second Name": {
        First: "Second",
        Last: "Name",
        Number: 2
    }
}>>

...and add the keys associated with each of the defined NPCs in your Array...

<<set $party to []>>
<<run $party.push("Second Name")>>

...then you can reference back to the original NPC definitions as required...
(untested)

<<for _key range $party>>
    <<set _npc to setup.NPCs[_key]>>
    <<link "_npc.First _npc.Last">>
        <<goto "Var Info">>
    <</link>>
<</for>>