# LuaTeX Lua API Type definitions for the Lua API of `LuaTeX` and related projects. ![](resources/screencasts/node.new.gif) [LuaTeX](http://luatex.org) has a very large [Lua](https://www.lua.org) API. This project tries to make this API accessible in the text editor of your choice. This is made possible by the [lua-language-server](https://github.com/LuaLS/lua-language-server) - a server that implements the [Language Server Protocol (LSP)](https://en.wikipedia.org/wiki/Language_Server_Protocol) for the `Lua` language. Features such as code completion, syntax highlighting and marking of warnings and errors, should therefore not only be possible in [Visual Studio Code](https://code.visualstudio.com), but in a [large number of editors](https://langserver.org/#implementations-client) that support the `LSP`. ## Subprojects * [lualatex](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/tree/main/library/lualatex) * [lualibs](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/tree/main/library/lualibs) * [luametatex](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/tree/main/library/luametatex) * [luaotfload](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/tree/main/library/luaotfload) * [luatex](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/tree/main/library/luatex) ## Distribution ... ## via CTAN ![](resources/images/Screenshot_CTAN.png) The type definitions are published on [CTAN](https://www.ctan.org/pkg/luatex-type-definitions) as a single file to avoid cluttering the CTAN directory with many individual Lua files. Since this one file is just under 1.5 MB in size, a configuration must be made so that the language server can load the file. The following configuration example sets the preload file size to a maximum of 5000 kB. ```json { "Lua.workspace.preloadFileSize": 5000, } ``` There are several ways to include type definitions in a project. The easiest way is to copy the file into the project folder. Or you can use the configuration `Lua.workspace.library`: ```json { "Lua.workspace.library": ["/path/to/luatex-type-definitions.lua"] } ``` ### via Visual Studio Code Extension ![](resources/images/Screenshot_VSCode-extension.png) * [Visual Studio Code LuaTeX Extension](https://github.com/Josef-Friedrich/vscode_LuaTeX_Lua-API) ← [library](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/tree/main/library) ### via LuaCATS git respositories ![](resources/images/Screenshot_LuaCATS.png) [LuaCATS](https://github.com/LuaCATS) is a [Github](https://github.com) organisation and stands for *“Lua Comment And Type System”*. This organization provides a place for community projects to live. These projects are [addons](https://luals.github.io/wiki/addons) for popular libraries/frameworks. The repositories in this organization are used by [LLS-Addons](https://github.com/LuaLS/LLS-Addons), a repository that is used by the [addon manager](https://luals.github.io/wiki/addons/#addon-manager) of the [VS Code extension](https://marketplace.visualstudio.com/items?itemName=sumneko.lua) for the [Lua Language Server]([lls](https://github.com/LuaLS/lua-language-server)). #### All related LuaCATS repositories This repositories in LuaCATS are related to this project: * [lmathx](https://github.com/LuaCATS/lmathx) * [lpeg](https://github.com/LuaCATS/lpeg) * [luafilesystem](https://github.com/LuaCATS/luafilesystem) * [luaharfbuzz](https://github.com/LuaCATS/luaharfbuzz) * [luasocket](https://github.com/LuaCATS/luasocket) * [luazip](https://github.com/LuaCATS/luazip) * [lzlib](https://github.com/LuaCATS/lzlib) * [md5](https://github.com/LuaCATS/md5) * [slnunicode](https://github.com/LuaCATS/slnunicode) * [tex-lualatex](https://github.com/LuaCATS/tex-lualatex) * [tex-lualibs](https://github.com/LuaCATS/tex-lualibs) * [tex-luametatex](https://github.com/LuaCATS/tex-luametatex) * [tex-luatex](https://github.com/LuaCATS/tex-luatex) #### Upstream LuaCATS repositories The following repositories are *upstream* projects. This means: The type definitions are developed in a LuaCATS repository and *pulled* in by this project. * [LuaCATS: lmathx](https://github.com/LuaCATS/lmathx) → [library/luametatex/lmathx.lua](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/library/luametatex/lmathx.lua) * [LuaCATS: lpeg](https://github.com/LuaCATS/lpeg) → [library/luatex/lpeg.lua](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/library/luatex/lpeg.lua) * [LuaCATS: luaharfbuzz](https://github.com/LuaCATS/luaharfbuzz) → [library/luatex/luaharfbuzz.lua](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/library/luatex/luaharfbuzz.lua) * [LuaCATS: luasocket](https://github.com/LuaCATS/luasocket) → [library/luatex/socket.lua](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/library/luatex/socket.lua) → [library/luatex/mime.lua](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/library/luatex/mime.lua) * [LuaCATS: luazip](https://github.com/LuaCATS/luazip) → [library/luatex/zip.lua](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/library/luatex/zip.lua) * [LuaCATS: lzlib](https://github.com/LuaCATS/lzlib) → [library/luatex/zlib.lua](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/library/luatex/zlib.lua) * [LuaCATS: md5](https://github.com/LuaCATS/md5) → [library/luatex/md5.lua](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/library/luatex/md5.lua) * [LuaCATS: slnunicode](https://github.com/LuaCATS/slnunicode) → [library/luatex/unicode.lua](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/library/luatex/unicode.lua) #### Subprojects (push) detached from this repository The following repositories are *downstream* projects. This means: The type definitions are developed in this project. They are then *pushed* into a LuaCATS repository. * [LuaCATS: tex-lualatex](https://github.com/LuaCATS/tex-lualatex) ← [library/lualatex](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/tree/main/library/lualatex) * [LuaCATS: tex-luatex](https://github.com/LuaCATS/tex-luatex) ← [library/luatex](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/tree/main/library/luatex) * [LuaCATS: tex-lualibs](https://github.com/LuaCATS/tex-lualibs) ← [library/lualibs](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/tree/main/library/lualibs) * [LuaCATS: tex-luametatex](https://github.com/LuaCATS/tex-luametatex) ← [library/luametatex](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/tree/main/library/luametatex) ## Directory structure of the repository In the subfolder `library` are files named after the global libraries they document. For example, the `library/tex.lua` file contains the documentation for the `tex` library. These *Lua* files don’t contain real *Lua* code. They consist only of function bodies and empty tables. The main focus is in the docstrings. The API documentation is written in a [well documented annotation format](https://luals.github.io/wiki/annotations). This format is based on the [EmmyLua](https://emmylua.github.io) format. Unfortunately, the *Lua* community has not yet been able to agree on a standarized annotation format. Many *Lua* project are documented in the [LDoc](https://github.com/lunarmodules/LDoc) format. However, the differences between these formats are marginal. ### Directory `library` The actual definitions are located in the directory `library`. This directory is divided into further subdirectories. In the folder `luatex` you will find the definitions that the engine *LuaTeX* provides. The folder `lualibs` documents the extension library of the same name. If you use `lualatex`, you may be interested in the folder of the same name. ### Directory `resources` The folder `resources` contains *TeX* manuals and *HTML* online documentation converted into *Lua* docstrings. ### Directory `examples` The `example` folder contains *TeX* and *Lua* files for demonstrating and testing the documented Lua API. ## Current version 2025/07/24 v0.2.0 ## License Copyright (C) 2022-2025 by Josef Friedrich ------------------------------------------------------------------------ This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . ## Installation / Setup for Visual Studio Code Install [Visual Studio Code](https://code.visualstudio.com/) and the [lua-language-server](https://marketplace.visualstudio.com/items?itemName=sumneko.lua). ``` git clone https://github.com/Josef-Friedrich/LuaTeX_Lua-API.git ``` `.vscode/settings.json`: ```json { "Lua.workspace.library": [ "/library" ] } ``` ## How to contribute The preferred method of contributing to the project is via Github pull requests. You can also email patches to josef@friedrich.rocks. It is ok if you only document the data types of the input parameters. Use imperative mood for the first line: https://peps.python.org/pep-0257/ `Please contribute!` messages Default message: ```lua ---😱 [Types](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/library/luatex/pdf.lua) incomplete or incorrect? 🙏 [Please contribute!](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/pulls) ``` No documentation at all: ```lua --- ---Warning! Undocumented code!

---TODO: Please contribute ---https://github.com/Josef-Friedrich/LuaTeX_Lua-API#how-to-contribute ``` ### Minimal example of `tex.sp()` ```lua --- ---@param s string function tex.sp(s) end ``` ### Less minimal example of `tex.sp()` ```lua --- ---@param s string --- ---@return integer function tex.sp(s) end ``` Or if you have more time you can also expand the documentation to this level: ### Prime example of `tex.sp()` ```lua ---@meta tex = {} --- ---Convert a string `s` that represents an explicit ---dimension into an integer number of scaled points. --- ---For parsing the string, the same scanning and conversion rules are used that ---*LuaTeX* would use if it was scanning a dimension specifier in its *TeX*-like ---input language (this includes generating errors for bad values), expect for the ---following: --- ---* only explicit values are allowed, control sequences are not handled ---* infinite dimension units (`fil...`) are forbidden ---* `mu` units do not generate an error (but may not be useful either) --- ---__Example:__ --- ---```lua ---local scaled_points = tex.sp('1cm') ---print(scaled_points) -- 1864679 ---``` --- ---__Reference:__ --- ---* `LuaTeX` manual: 10.3.15.5 `sp` page 204 ---* Source file of the `LuaTeX` manual: [luatex-tex.tex#L1386-L1413](https://gitlab.lisn.upsaclay.fr/texlive/luatex/-/blob/f52b099f3e01d53dc03b315e1909245c3d5418d3/manual/luatex-tex.tex#L1386-L1413) --- ---@param s string # A string to convert into scaled points. --- ---@return integer # The dimension in the scaled points format. function tex.sp(s) end ``` The docstring above is rendered as follows in Visual Studio Code: ![](resources/images/tex.sp.png) The description text can be or was taken from the official [LuaTeX reference manual](https://github.com/TeX-Live/luatex/tree/trunk/manual). In the project folder [resources/manuals/luatex](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/tree/main/resources/manuals/luatex) you will find slightly edited `Lua` versions of the `LuaTeX` manual sources. 1. [Preamble](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/01_preamble.tex.lua) 2. [Basic TEX enhancements](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/02_enhancements.tex.lua) 3. [Modifications](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/03_modifications.tex.lua) 4. [Using LUATEX](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/04_lua.tex.lua) 5. [Languages, characters, fonts and glyphs](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/05_languages.tex.lua) 6. [Font structure](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/06_fonts.tex.lua) 7. [Math](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/07_math.tex.lua) 8. [Nodes](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/08_nodes.tex.lua) 9. [LUA callbacks](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/09_callbacks.tex.lua) 10. [The TEX related libraries](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/10_tex.tex.lua) 11. [The graphic libraries](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/11_graphics.tex.lua) 12. [The fontloader](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/12_fontloader.tex.lua) 13. [The HarfBuzz libraries](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/13_harfbuzz.tex.lua) 14. [The backend libraries](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/luatex/14_backend.tex.lua) This quick hacked and very ugly Python script [resources/manuals/convert-tex-to-lua-docstrings.py](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/manuals/convert-tex-to-lua-docstrings.py) was used to convert the source files. ### Navigation table `_N` Some Lua files contain a table named `_N`. `_N` stands for `navigation`. With the help of this table and the outline view of the editor, it is easier to navigate through the documentation. The name is inspired by the global Lua table `_G`. Many parts of the documentation, such as the definition of the various `Node` classes, are not shown in the outline. If the API documentation is published, the `_N` table can be commented out. ### Documentation of function overloading `LuaTeX` makes extensive use of function overloading. The following example is taken from the `LuaTeX` manual: ``` w, h, d = node.dimensions( n) w, h, d = node.dimensions( n, dir) w, h, d = node.dimensions( n, t) w, h, d = node.dimensions( n, t, dir) w, h, d = node.dimensions( glue_set, glue_sign, glue_order, n) w, h, d = node.dimensions( glue_set, glue_sign, glue_order, n, dir) w, h, d = node.dimensions( glue_set, glue_sign, glue_order, n, t) w, h, d = node.dimensions( glue_set, glue_sign, glue_order, n, t, dir) ``` This can easily be done by documenting the function with the same name but different signatures multiple times. [Issue for further improvement of the function loading](https://github.com/sumneko/lua-language-server/issues/1456) Function overloading in `tex.sp()` ![](resources/images/tex.sp_overload.png) ### Documentation of nodes A node (object) can be described by the `@class` annotation and provided with some documentation about its attributes using `@field`. There is a base class `Node` for all node type classes. ```lua --- ---A node that comprise actual typesetting commands. A few fields are ---present in all nodes regardless of their type, these are: --- ---@class Node ---@field next Node|nil # the next node in a list, or nil ---@field prev Node|nil # That prev field is always present, but only initialized on explicit request ... ``` The `KernNode` class for example inherits from `Node` and represents a kern node. ```lua --- ---The `kern` command creates such nodes but for instance the font and math ---machinery can also add them. --- ---@class KernNode: Node ---@field subtype KernNodeSubtype ---@field kern integer # Fixed horizontal or vertical advance (in scaled points) ``` ```lua ---@alias KernNodeSubtype ---|0 # fontkern ---|1 # userkern ---|2 # accentkern ---|3 # italiccorrection ``` The `@cast` annotation forces a unspecific node to a distinct node type. ```lua while n do if n.id == node.id('kern') then ---@cast n KernNode print(n.kern) end n = n.next end ``` Use `--[[@as ]]` to force a node type onto an expression. ```lua local kern = node.new('kern') --[[@as KernNode]] ``` ![](resources/images/cast.png) ### Documentation of callback functions How a callback function is documented is shown using the `pre_linebreak_filter` as an example. #### @alias `PreLinebreakFilterGroupCode` ```lua --- ---The string called `groupcode` identifies the nodelist's context within ---*TeX*'s processing. The range of possibilities is given in the table below, but ---not all of those can actually appear in `pre_linebreak_filter`, some are ---for the `hpack_filter` and `vpack_filter` callbacks that will be ---explained in the next two paragraphs. ---@alias PreLinebreakFilterGroupCode ---|'' # main vertical list ---|'hbox' # hbox` in horizontal mode ---|'adjusted_hbox' #hbox` in vertical mode ---|'vbox' # vbox` ---|'vtop' # vtop' # ---|'align' # halign` or `valign` ---|'disc' # discretionaries ---|'insert' # packaging an insert ---|'vcenter' # vcenter` ---|'local_box' # localleftbox` or `localrightbox` ---|'split_off' # top of a `vsplit` ---|'split_keep' # remainder of a `vsplit` ---|'align_set' # alignment cell ---|'fin_row' # alignment row ``` #### @alias `NodeCallbackReturn` ```lua --- ---As for all the callbacks that deal with nodes, the return value can be one of ---three things: --- ---* boolean `true` signals successful processing ---* `` signals that the “head” node should be replaced by the --- returned node ---* boolean `false` signals that the “head” node list should be --- ignored and flushed from memory ---@alias NodeCallbackReturn true|false|Node ``` #### @alias `PreLinebreakFilter` ```lua --- ---# `pre_linebreak_filter` callback --- ---This callback is called just before *LuaTeX* starts converting a list of nodes ---into a stack of `hbox`es, after the addition of `parfillskip`. --- ---```lua ------@type PreLinebreakFilter ---function(head, groupcode) --- --- true|false|node --- return true ---end ---``` --- ---This callback does not replace any internal code. ---@alias PreLinebreakFilter fun(head: Node, groupcode: PreLinebreakFilterGroupCode): NodeCallbackReturn ``` Annotation your custom callback function with `@type`. ```lua ---@type PreLinebreakFilter local function visit_nodes(head, group) return true end luatexbase.add_to_callback('pre_linebreak_filter', visit_nodes, 'visit nodes') ``` ![](resources/images/PreLinebreakFilter.png) Quick info `node.id(type)` ![](resources/images/node.id.png) Type error in `node.id(type)` ![](resources/images/node.id_wrong-type.png) `node.id(type)` type definition ![](resources/images/node.id_definition.png) Quick info `node.write(n)` ![](resources/images/node.write.png) Documentation for the field `data` of the `pdf_colorstack` node: ![](resources/images/PdfColorstockWhatsitNode.data.png) ## Documentation * [LuaTeX Repo](https://gitlab.lisn.upsaclay.fr/texlive/luatex/) [LuaTeX Mirror](https://github.com/TeX-Live/luatex) * [pdfTeX Mirror](https://github.com/tex-mirror/pdftex) ## Howtos * [Custom libraries](https://github.com/sumneko/lua-language-server/wiki/Libraries#custom) * [@meta annotation](https://github.com/sumneko/lua-language-server/wiki/Annotations#meta) ## Other type definition / stub repos: * [Template of the Lua interface itself](https://github.com/sumneko/lua-language-server/tree/master/meta/template) * [In the lua-language-server included 3rd party libraries](https://github.com/sumneko/lua-language-server/tree/master/meta/3rd) * [FiveM Lua Stubs](https://github.com/jamie-34254/fivem_lua_stubs) ## References ```lua --- ---__Reference:__ --- ---* Corresponding C source code: [ltexlib.c#L1430-L1436](https://gitlab.lisn.upsaclay.fr/texlive/luatex/-/blob/f52b099f3e01d53dc03b315e1909245c3d5418d3/source/texk/web2c/luatexdir/lua/ltexlib.c#L1430-L1436) ---* Source file of the `LuaTeX` manual: [luatex-nodes.tex#L1199-L1211](https://gitlab.lisn.upsaclay.fr/texlive/luatex/-/blob/f52b099f3e01d53dc03b315e1909245c3d5418d3/manual/luatex-nodes.tex#L1199-L1211) ---* Corresponding plain TeX control sequence: [\sfcode](https://www.tug.org/utilities/plain/cseq.html#sfcode-rp) ---* Victor Eijkhout. “TeX by Topic” (1991, 2007) [page 185](http://mirrors.ctan.org/info/texbytopic/TeXbyTopic.pdf) ---* Donald Ervin Knuth. “The TexBook” (1984): page 76. Also: 76, 271, 285, 363, 433. [TeX-Source](https://ctan.org/tex-archive/systems/knuth/dist/tex/texbook.tex) [PDF](https://visualmatheditor.equatheque.net/doc/texbook.pdf) ---David Bausum. “TeX Reference Manual” (2002) [](https://www.tug.org/utilities/plain/cseq.html) ``` ```lua --- ---__Reference:__ --- ---* Source file of the `LuaTeX` manual: []() --- ``` ## Global namespaces The Makefile provides targets for printing the global namespace available on the specific engines. The Makefile uses some Lua functions to output all functions and tables of the global namespace that can be found in [utils.lua](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/utils.lua). To print the [LuaTeX global namespace](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/namespaces/luatex.md): ``` make namespace_luatex ``` To print the [LuaMetaTeX global namespace](https://github.com/Josef-Friedrich/LuaTeX_Lua-API/blob/main/resources/namespaces/luametatex_luaonly.md): ``` make namespace_luametatex ```