Simplest way to do an Inventory in Twine 2?

rayotus

So, how do you all handle inventories in Twine? I can imagine using (history: ) and just sending the user to passages when they take an item. But then you can't easily remove/re-add items. Do you use the (dataset: ) array? Can you append or concatenate dataset arrays?

rayotus

P.S. Harlowe

timsamoff

I do it via variables. I.e., if someone gets a shield, you can set the variable $shield to true. Then, I use if/else statements to check those variables.

Datasets might be more efficient (and, yes, you can append to them, etc.), but I always found variables easier to track.

If you need actual code examples, let us know.

rayotus

Ah. Of course. That is a simple and easy way to do it. I think I just got caught up in trying to do it a more complicated way. Now that I think about it, it was so I could print out a player's inventory in one go instead of a bunch of statements to check for everything the player could have. But really, it's not a bad idea to keep a passage with all list of all your variables anyway, so...

rayotus

... and the nice thing about variables is they have some flexibility. Like you could set $matches to 6, and then $matches = $matches-1 anytime a player uses one.

Dominia

You can do a basic inventory via the (dataset:) macro.

I've used a combination of the dataset and count macros and the contains operator. Did what I needed at the time. Might be something you could use as well.

From @L's Twine 2.0 Harlowe Guide

(dataset:) This macro produces a Javascript Set, which is a more limited form of array that does not have numeric properties - you can only query whether it contains a value using contains or is in. It can be used for simplifying (if:) statements - instead of writing (if: $a is "sword" or $a is "axe" or $a is "dagger") dozens of times, you can write (set: $weapons to (dataset: "sword", "axe", "dagger")) and then simply write (if: $a is in $weapons).

contains: This operator is used to check if a string or some text contains another substring. For instance, "Red" contains "R" evaluates to true. (It can also be used with arrays to check for inclusion: (array: 1,4,5) contains 4 evaluates to true.)

(count:): This macro takes an array and a value, and returns the number of times the value appears within the array. (count: $a, "Egg") returns the number of times the string "Egg" is a value in $a. It's like the contains operator, but it produces a number rather than just true or false.

Sage

@rayotus

I found this, I think on glorious trainwreck... but it works great:

<<set $inv = ["Dagger", "Shield", "Potion"] >>
<<if $inv.length is 0>>You have nothing.
<<else>>
Your inventory contains:
<<print $inv.join("\n")>>
<<endif>>


You decide to [[drop your potion]]

―> (new room)

<<script>>
// Removes an element from an array.
// String value: the value to search and remove.
// return: an array with the removed element; false otherwise.
Array.prototype.remove = function(value) {
var idx = this.indexOf(value);
if (idx != -1) {
return this.splice(idx, 1); // The second parameter is the number of elements to remove.
}
return false;
}
<</script>>

It breaks on the ground and just in front of you, and you see....

<<set $inv.remove('Potion')>>
Your inventory now only contains:
<<print $inv.join("\n")>>

If I miscredited it, let me know... but I think I saw it there.

—Sage.

AvaJarvis

It works great for SugarCube, probably doesn't work for Harlowe.

Sage

@AvaJarvis
Missed that, above, thanks.

greyelf

The following is a Harlowe version of @Sage's post:

1. Place the following in your story's Story Javascript area:

// Removes an element from an array.
// String value: the value to search and remove.
// return: an array with the removed element; false otherwise.
Array.prototype.remove = function(value) {
	var idx = this.indexOf(value);
	if (idx != -1) {
		// The second parameter is the number of elements to remove.
		return this.splice(idx, 1); 
	}
	return false;
};

2. Copy the following In your start passage:

(set: $inv to (array: "Dagger", "Shield", "Potion"))
(if: $inv.length is 0)[You have nothing.]
(else:)[Your inventory contains:
(print: $inv.join("\n"))
]

You decide to [[drop your potion]]

3. Create a new passage titled drop your potion and copy the following into it:

It breaks on the ground and just in front of you, and you see....

(set: $dummy to $inv.remove("Potion"))
Your inventory now only contains:
(print: $inv.join("\n"))

4. Dance around with your hands in the air like you just don't care...

timsamoff

But I wanted to dance around…