VoxeLibre/mods/HELP/doc/doc_items/API.md

API documentation for doc_items

Introduction

This document explains the API of doc_items. It contains a reference of all functions.

Quick start

The most common use case for using this API requires only to set some hand-written help texts for your items.

The preferred way is to add the following optional fields to the item definition when using minetest.register_node, etc.:

• _doc_items_longdesc: Long description of this item. Describe here what this item is, what it is for, its purpose, etc.
• _doc_items_usagehelp: Description of how this item can be used. Only set this if needed, e.g. standard mining tools don't need this.

Example:

minetest.register_node("example:dice", {
    description = "Dice",
    _doc_items_longdesc = "A decorative dice which shows the numbers 1-6 on its sides.",
    _doc_items_usagehelp = "Right-click the dice to roll it.",
    tiles = { "example_dice.png" },
    is_ground_content = false,
    --[[ and so on … ]]
})

When using this method, your mod does not need additional dependencies.

See below for some recommendations on writing good help texts.

If you need more customization, read ahead. ;-)

New item fields

This mod adds support for new fields of the item definition. They allow for easy and quick manipulation of the item help entries. All fields are optional.

• _doc_items_longdesc: Long description
• _doc_items_usagehelp: Usage help
• _doc_items_image: Entry image (default: inventory image)
• _doc_items_hidden: Whether entry is hidden (default: false for air and hand, true for everything else)
• _doc_items_create_entry: Whether to create an entry for this item (default: true)
• _doc_items_entry_name: The title of the entry. By default, this is the same as the description field of the item (discarding text after the first newline). This field is required if the description is empty
• _doc_items_durability: This field is for describing how long a tool can be used before it breaks. Choose one data type:
  • It it is a number: Fixed number of uses before it breaks
  • If it is a string: Free-form text which explains how the durability works. Try to keep it short and only use it if the other types won't work

A full explanation of these fields is provided below.

Concepts

This section explains the core concepts of an item help entry in-depth.

Factoids

Basically, a factoid is usually a single sentence telling the player a specific fact about the item. The task of each factoid is to basically convert parts of the item definition to useful, readable, understandable text.

Example: It's a fact that default:sand has the group falling_node=1. A factoid for this is basically just a simple conditional which puts the the sentence “This block is affected to gravity and can fall.” into the text if the node is member of said group.

Factoids can be more complex than that. The factoid for node drops needs to account for different drop types and probabilities, etc.

doc_items has many predefined factoids already. This includes all “special” groups (like falling_node), drops, mining capabilities, punch interval, and much more.

Custom factoids can be added with doc.sub.items.register_factoid.

The idea behind factoids is to generate as much information as possible automatically to reduce redundancy, inconsistencies and the workload of hand- written descriptions.

Long description and usage help

Factoids are not always sufficient to describe an item. This is the case for facts where the item definition can not be used to automatically generate texts. Examples: Custom formspecs, ABMs, special tool action on right-click.

That's where the long description and usage help comes into play. Those are two texts which are written manually for a specific item.

Roughly, the long description is for describing what the item is, how it acts, what it is for. The usage help is for explaining how the item can be used. It is less important for standard mining tools and weapons.

There is no hard length limit for the long description and the usage help.

Recommendations for long description

The long description should roughly contain the following info:

• What the item does
• What it is good for
• How it may be generated in the world
• Maybe some background info if you're in a funny mood
• Notable information which doesn't fit elsewhere

The description should normally not contain:

• Information which is already covered by factoids, like digging groups, damage, group memberships, etc.
• How the item can be used
• Direct information about other items
• Any other redundant information
• Crafting recipes

One exception from the rule may be for highlighting the most important purpose of a simple item, like that coal lumps are primarily used as fuel.

Sometimes, a long description is not necessary because the item is already exhaustively explained by factoids.

For very simple items, consider using one of the template texts (see below).

Minimal style guide: Use complete sentences.

Recommendations for usage help

The usage help should only be set for items which are in some way special in their usage. Standard tools and weapons should never have an usage help.

The rule of thumb is this: If a new player who already knows the Luanti basics, but not this item, will not directly know how to use this item, then the usage help should be added. If basic Luanti knowledge or existing factoids are completely sufficient, usage help should not be added.

The recommendations for what not to put into the usage help is the same as for long descriptions.

Template texts

For your convenience, a few template texts are provided for common texts to avoid redundancy and to increase consistency for simple things. Read init.lua to see the actual texts.

Long description

• doc.sub.items.temp.build: For building blocks like the brick block in Minetest Game
• doc.sub.items.temp.deco: For other decorational blocks.
• doc.sub.items.temp.craftitem: For items solely or almost solely used for crafting

Usage help

• doc.sub.items.temp.eat: For eatable items using the on_use=minetest.item_eat(1) idiom
• doc.sub.items.temp.eat_bad: Same as above, but eating them is considered a bad idea
• doc.sub.items.temp.rotate_node: For nodes with on_place=minetest.rotate_node, explains placement and rotation

Entry creation

By default, an entry for each item is added automatically, except for items without a description (description == nil). This behaviour can be changed on a per-item basis.

By setting the item definition's field _doc_items_create_entry to true or falseyou can explicitly define whether this item should get its own entry.

Suppressing an entry is useful for items which aren't supposed to be directly seen or obtained by the player or if they are only used for technical and/or internal purposes. Another possible reason to suppress an entry is to scrub the entry list of lots of very similar related items where the difference is too small to justify two separate entries (e.g. burning furnace vs inactive furnace, because the gameplay mechanics are identical for both).

Hidden entries

Hidden entries are entries which are not visible in the list of entries. This concept directly comes from the Documentation System. The entry will still be created, it is just not selectable by normal means. Players might be able to “unlock” an entry later. Refer to the API documentation of the Documentation System to learn more.

By default, all entries are hidden except air and the hand.

To mark an entry as hidden, add the field _doc_items_hidden=true to its item definition. To make sure an entry is never hidden, add _doc_items_hidden=false instead (this rarely needs to be specified explicitly).

Hand and air

The mod adds some default help texts for the hand and the air which are written in a way that they probably are true for most games out of the box, but especially the hand help text is kept intentionally vague. If you want to change these help texts or the entry names or other attributes, just add _doc_items_* fields to the item definition, either by re-defining or overwriting these items (e.g. with minetest.override_item).

In the mod doc_minetest_game, the default hand help text is overwritten to explain the hand in more detail, especially the hand behaviour in Creative Mode.

Functions

This is the reference of all available functions in this API.

doc.sub.items.register_factoid(category_id, factoid_type, factoid_generator)

Add a custom factoid (see above) for the specified category.

• category_id: The help category for which the factoid applies:
  • "nodes": Blocks
  • "tools": Tools and weapons
  • "craftitems": Misc. items
  • nil: All of the above
• factoid_type: Rough categorization of the factoid's content, used to optimize the final text display. This currently determines where in the entry text the factoid appears. Possible values:
  • For all items:
    • "use": It's about using the item in some way (written right after the fixed usage help)
    • "groups": Group-related factoid (very vague)
    • "misc": Factoid doesn't fit anywhere else, is shown near the end
  • For nodes only:
    • damage: Related to player/mob damage or health
    • movement: Related to player movement on, in or at node
    • sound: Related to node sounds
    • gravity: Related to gravity (e.g. falling node)
    • drop_destroy: Related to node being destroyed or node dropping as an item
    • light: Related to node light (luminance)
    • mining: Related to mining
    • drops: Related to node drops
• factoid_generator: A function which turns item definition into a string (see blow)

factoid_generator(itemstring, def)

itemstring is the itemstring of the item to be documented, and def is the complete item definition table (from Luanti).

This function must return a helpful string which turns a part of the item's definition into an useful sentence or text. The text can contain newlines, but it must not end with a newline.

This function must always return a string. If you don't want to add any text, return the empty string.

Style guide: Try to use complete sentences and avoid too many newlines.

Example

This factoid will add the sentence “This block will extinguish nearby fire.” to all blocks which are member of the group puts_out_fire.

doc.sub.items.register_factoid("nodes", "groups", function(itemstring, def)
    if def.groups.puts_out_fire ~= nil then
        return "This block will extinguish nearby fire."
    else
        return ""
    end
end)

doc.sub.items.disable_core_factoid(factoid_name)

This function removes a core (built-in) factoid entirely, its text will never be displayed in any entry then.

Parameter

factoid_name chooses the factoid you want to disable. The following core factoids can be disabled:

• "node_mining": Mining properties of nodes
• "tool_capabilities": Tool capabilities such as digging times
• "groups": Group memberships
• "fuel": How long the item burns as a fuel and if there's a leftover
• "itemstring": The itemstring
• "drops": Node drops
• "connects_to": Tells to which nodes the node connects to
• "light": Light and transparency information for nodes
• "drop_destroy": Information about when the node causes to create its “drop” and if it gets destroyed by flooding
• "gravity": Factoid for falling_node group
• "sounds": Infos about sound effects related to the item
• "node_damage": Direct damage and drowning damage caused by nodes
• "node_movement": Nodes affecting player movement
• "liquid": Liquid-related infos of a node
• "basics": Collection of many basic factoids: The custom help texts, pointability, collidability, range, stack size, liquids_pointable, “punches don't work as usual”. Be careful with this one!

Background

Normally, the core factoids are written in a very general-purpose style, so this function might not be needed at all. But it might be useful for games and mods which radically break with some of the underlying core assumptions in Luanti. For example, if your mod completely changes the digging system, the help texts provided by doc_items are probably incorrect, so you can disable node_mining and register a custom factoid as a replacement.

Please do not use this function lightly because it touches the very core of doc_items. Try to understand a core factoid before you consider to disable it. If you think a core factoid is just broken or buggy in general, please file a bug instead.

doc.sub.items.add_friendly_group_names(groupnames)

Use this function so set some more readable group names to show them in the formspec, since the internal group names are somewhat cryptic to players.

groupnames is a table where the keys are the “internal” group names and the values are the group names which will be actually shown in the Documentation System.

Note: This function is mostly there to work around a problem in Luanti as it does not support “friendly” group names, which means exposing groups to an interface is not pretty. Therefore, this function may be deprecated when Luanti supports such a thing.

doc.sub.items.get_group_name(internal_group_name)

Returns the group name of the specified group as displayed by this mod. If the setting doc_items_friendly_group_names is true, this might return a “friendly” group name (see above). If no friendly group name exists, internal_group_name is returned. If doc_items_friendly_group_names is false, the argument is always returned.

doc.sub.items.add_notable_groups(groupnames)

Add a list of groups you think are notable enough to be mentioned in the “This item belongs to the following groups: (…)” factoid. This factoid is intended to give a quick rundown of misc. groups which don't fit to other factoids, yet they are still somewhat relevant to gameplay.

groupnames is a table of group names you wish to add.

What groups should be added

What is “notable” is subjective, but there are some guidelines:

Do add a group if:

• It is used in an ABM
• It is used for a custom interaction with another item
• It is simple enough for the player to know an item is member of this group
• You want to refer to this group in help texts
• The “don'ts” below don't apply

Do not add a group if:

• It is only used for crafting, connects_to, mining times or damage groups
• A factoid covering this group already exists
• The group membership itself requires an explanation (consider writing a factoid instead)
• The group has no gameplay relevance
• Group rating is important to gameplay (consider writing a factoid instead)

Groups which are used for crafting or in the connects_to field of item definitions are already automatically added to this factoid.

Examples for good additions

• A group where its members can be placed in bookshelves. so this group meets the “custom interaction” criterion
• water in Minetest Game: Used for water nodes in the obsidian ABM
• sand in Minetest Game: Used for the cactus growth ABM, but also crafting. Since it is not only used for crafting, it is OK to be added

Examples for bad additions

• stick in Minetest Game: This group appears in many crafting recipes and has no other use. It is already added automatically
• A group in which members turn into obsidian when they touch water (ABM): This group is not trivial and should be introduced in a factoid instead
• cracky in Min
• dig_immediate: This group is already covered by the default factoids of this mod

Groups interpretations

Nodes which are technically a liquid will not be considered liquids by this mod if the group fake_liquid=1 is used. Useful for stuff like cobwebs.

Dependencies

If you only add the custom fields to your items, you do not need to depend on this mod. If you use anything else from this mod (e.g. a function), you probably do need to depend (optionally or mandatorily) on this mod.