minetest_modding_book/en/chapters/itemstacks.md

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Introduction

In this chapter you will learn how to use ItemStacks.

• Creating ItemStacks
• Name and Count
• Adding and Taking Items
• Wear
• Lua Tables
• Metadata
• More Methods

Creating ItemStacks

An item stack is a... stack of items. It's basically just an item type with a count of items in the stack.

You can create a stack like so:

{% highlight lua %} local items = ItemStack("default:dirt") local items = ItemStack("default:stone 99") {% endhighlight %}

You could alternatively create a blank ItemStack and fill it using methods:

{% highlight lua %} local items = ItemStack() if items:set_name("default:dirt") then items:set_count(99) else print("An error occured!") end {% endhighlight %}

And you can copy stacks like this:

{% highlight lua %} local items2 = ItemStack(items) {% endhighlight %}

Name and Count

{% highlight lua %} local items = ItemStack("default:stone") print(items:get_name()) -- default:stone print(items:get_count()) -- 1

items:set_count(99) print(items:get_name()) -- default:stone print(items:get_count()) -- 99

if items:set_name("default:dirt") then print(items:get_name()) -- default:dirt print(items:get_count()) -- 99 else error("This shouldn't happen") end {% endhighlight %}

Adding and Taking Items

Adding

Use add_item to add items to an ItemStack. An ItemStack of the items that could not be added is returned.

{% highlight lua %} local items = ItemStack("default:stone 50") local to_add = ItemStack("default:stone 100") local leftovers = items:add_item(to_add)

print("Could not add" .. leftovers:get_count() .. " of the items.") -- ^ will be 51 {% endhighlight %}

Taking

The following code takes up to 100. If there aren't enough items in the stack, it will take as much as it can.

{% highlight lua %} local taken = items:take_item(100) -- taken is the ItemStack taken from the main ItemStack

print("Took " .. taken:get_count() .. " items") {% endhighlight %}

Wear

ItemStacks also have wear on them. Wear is a number out of 65535, the higher it is, the more wear.

You use add_wear(), get_wear() and set_wear(wear).

{% highlight lua %} local items = ItemStack("default:dirt") local max_uses = 10

-- This is done automatically when you use a tool that digs things -- It increases the wear of an item by one use. items:add_wear(65535 / (max_uses - 1)) {% endhighlight %}

When digging a node, the amount of wear a tool gets may depends on the node being dug. So max_uses varies depending on what is being dug.

Lua Tables

{% highlight lua %} local data = items:to_table() local items2 = ItemStack(data) {% endhighlight %}

Metadata

ItemStacks can also have a single field of metadata attached to them.

{% highlight lua %} local meta = items:get_metadata() print(dump(meta)) meta = meta .. " ha!" items:set_metadata(meta) -- if ran multiple times, would give " ha! ha! ha!" {% endhighlight %}

More Methods

Have a look at the list of methods for an ItemStack. There are a lot more available than talked about here.