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 Hello. I have a problem. If you execute code below it will work, but if you save and then load you will see that $EXTERNAL[$INTERNAL[0]] - undefined. I don't understand why. Is this bug or i need to know something about saves? I was working on a game in a month and it has many constructions like this. Need I to start again or it can be fixed with macros or something else?

<<set $INTERNAL = []>>
<<set $INTERNAL[0] = "Zero">>
<<set $EXTERNAL = []>>
<<set $EXTERNAL[$INTERNAL[0]] = "External">>



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Your example code may not be doing what you think it is, due to Array indexes being number based (starting with 0).

a. The $INTERNAL[0] = "Zero" line is adding a String value of "Zero" as the first item of the Array object contained within the $INTERNAL variable.

b. The $EXTERNAL[$INTERNAL[0]] = "External" line is adding an Object Member Property named "Zero" to the Array object contained within the $EXTERNAL variable, then assign a String value of "External" to that new object property.
warning: This practice may lead to issues if the Reader saves then re-load that save, due to the new property not correct being recreated during the load process.


re: Adding elements to an (Standard) Array.
I generally suggest using the <Array>.push() method to add items to an Array, as it stops the issue described in point B from occurring.

<<set $INTERNAL to []>>
<<set $INTERNAL.push("Zero")>>


re: Adding key based elements to a Collection:
1. Using a generic Object to store the key/value pairs:

<<set $EXTERNAL to {}>>
<<set $EXTERNAL[$INTERNAL[0]] to "External">>

2. Using a Javascript Map object to store the key/value pairs.

<<set $MAP to new Map()>>
<<set $MAP.set($INTERNAL[0], "External")>>


The TwineScript to access the elements would look like the following:


MAP = <<print $MAP.get($INTERNAL[0])>>


asked Jul 5, 2017 by (470 points)
edited Jul 5, 2017 by
[Twine 2.1.3/ Sugarcube 2.18.0] How to use arrays without push()?