NOTE: This is a beta.

LuaTree

An unfinished Lua source parser. Currently targets PUC-Lua 5.1 and LuaJIT 2.1.3.

PUC-Lua 5.2, 5.3 and 5.4 are planned, and a small amount of work has been done, but they have not been tested at all.

See the test files for some examples.

lua_parse API

parse.parse

Parses a Lua source string, converting it to a tree of nodes.

local root = parse.parse(str, lua_ver, jit)

str: The input string.
lua_ver: The Lua version, in string form: 5.1, 5.2, 5.3 or 5.4. The version affects lexing and parsing.
jit: true to treat 5.1 strings as LuaJIT code, false otherwise. (When enabled, lua_ver must be 5.1.)

Returns: A tree of nodes based on the source input.

parse.parseFile

A wrapper for parse.parse() that loads a file from disk.

local root = parse.parseFile(path, lua_ver, jit)

path: File path of the input source code.
lua_ver: The Lua version, in string form: 5.1, 5.2, 5.3 or 5.4. The version affects lexing and parsing.
jit: true to treat 5.1 strings as LuaJIT code, false otherwise. (When enabled, lua_ver must be 5.1.)

Returns: A tree of nodes based on the source input.

Notes: This is provided for convenience when working from the command line. When working from a host application that has its own way of loading files as strings (like in LÖVE's love.filesystem), use those functions instead.

lua_lex API

TODO

lua_out API

TODO!

Notes

Character Classes

In Lua, string character classes are determined by the current locale. This affects which characters are designated as alphanumeric, as whitespace, etc.

LuaJIT accepts non-ASCII characters for names. In practice, this means you can use multi-byte UTF-8 characters as part of variable identifiers: ¡ö¿, etc.

TODO: Follow up on this bit from the Lua 5.2 Reference Manual: "Lua identifiers cannot use locale-dependent letters."

Differences from the eBNF

Section 8 of the Lua Reference Manual provides the language syntax in eBNF form. (There are slight differences in 5.2, 5.3 and 5.4.) LuaTree mostly follows the grammar productions, with the following exceptions.

chunk

chunk is merged with block.

var, prefixexp, functioncall

var, prefixexp and functioncall are constructed using the same internal function. The reason is that var and prefixexp include each other in their productions.

The internal function that handles var, prefixexp and functioncall assembles nodes from the following token layout:

(Name | '(' exp ')') ('.' Name | '[' exp ']' | ':' Name args | args)*

The resulting node is a function if its last child is args.

References

Lua Reference Manuals: 5.1, 5.2, 5.3, 5.4
LuaJIT extensions
Libraries referenced and examined while developing LuaTree:
- ReFreezed/DumbLuaParser
- stravant/LuaMinify
- 2dengine/sstrict.lua. (See also the linked LÖVE forum thread for many tips on parsing Lua source code.)
- fab13n/metalua

License (MIT)

Copyright (c) 2024 RBTS

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

rabbitboots/lua_tree