mirror of
https://github.com/NixOS/nixpkgs.git
synced 2024-12-05 13:23:17 +00:00
259 lines
9.8 KiB
Markdown
259 lines
9.8 KiB
Markdown
# User’s Guide to Lua Infrastructure {#users-guide-to-lua-infrastructure}
|
||
|
||
## Using Lua {#using-lua}
|
||
|
||
### Overview of Lua {#overview-of-lua}
|
||
|
||
Several versions of the Lua interpreter are available: luajit, lua 5.1, 5.2, 5.3.
|
||
The attribute `lua` refers to the default interpreter, it is also possible to refer to specific versions, e.g. `lua5_2` refers to Lua 5.2.
|
||
|
||
Lua libraries are in separate sets, with one set per interpreter version.
|
||
|
||
The interpreters have several common attributes. One of these attributes is
|
||
`pkgs`, which is a package set of Lua libraries for this specific
|
||
interpreter. E.g., the `busted` package corresponding to the default interpreter
|
||
is `lua.pkgs.busted`, and the lua 5.2 version is `lua5_2.pkgs.busted`.
|
||
The main package set contains aliases to these package sets, e.g.
|
||
`luaPackages` refers to `lua5_1.pkgs` and `lua52Packages` to
|
||
`lua5_2.pkgs`.
|
||
|
||
### Installing Lua and packages {#installing-lua-and-packages}
|
||
|
||
#### Lua environment defined in separate `.nix` file {#lua-environment-defined-in-separate-.nix-file}
|
||
|
||
Create a file, e.g. `build.nix`, with the following expression
|
||
|
||
```nix
|
||
with import <nixpkgs> {};
|
||
|
||
lua5_2.withPackages (ps: with ps; [ busted luafilesystem ])
|
||
```
|
||
|
||
and install it in your profile with
|
||
|
||
```shell
|
||
nix-env -if build.nix
|
||
```
|
||
Now you can use the Lua interpreter, as well as the extra packages (`busted`,
|
||
`luafilesystem`) that you added to the environment.
|
||
|
||
#### Lua environment defined in `~/.config/nixpkgs/config.nix` {#lua-environment-defined-in-.confignixpkgsconfig.nix}
|
||
|
||
If you prefer to, you could also add the environment as a package override to the Nixpkgs set, e.g.
|
||
using `config.nix`,
|
||
|
||
```nix
|
||
{ # ...
|
||
|
||
packageOverrides = pkgs: with pkgs; {
|
||
myLuaEnv = lua5_2.withPackages (ps: with ps; [ busted luafilesystem ]);
|
||
};
|
||
}
|
||
```
|
||
|
||
and install it in your profile with
|
||
|
||
```shell
|
||
nix-env -iA nixpkgs.myLuaEnv
|
||
```
|
||
The environment is installed by referring to the attribute, and considering
|
||
the `nixpkgs` channel was used.
|
||
|
||
#### Lua environment defined in `/etc/nixos/configuration.nix` {#lua-environment-defined-in-etcnixosconfiguration.nix}
|
||
|
||
For the sake of completeness, here's another example how to install the environment system-wide.
|
||
|
||
```nix
|
||
{ # ...
|
||
|
||
environment.systemPackages = with pkgs; [
|
||
(lua.withPackages(ps: with ps; [ busted luafilesystem ]))
|
||
];
|
||
}
|
||
```
|
||
|
||
### How to override a Lua package using overlays? {#how-to-override-a-lua-package-using-overlays}
|
||
|
||
Use the following overlay template:
|
||
|
||
```nix
|
||
final: prev:
|
||
{
|
||
|
||
lua = prev.lua.override {
|
||
packageOverrides = luaself: luaprev: {
|
||
|
||
luarocks-nix = luaprev.luarocks-nix.overrideAttrs(oa: {
|
||
pname = "luarocks-nix";
|
||
src = /home/my_luarocks/repository;
|
||
});
|
||
};
|
||
|
||
luaPackages = lua.pkgs;
|
||
}
|
||
```
|
||
|
||
### Temporary Lua environment with `nix-shell` {#temporary-lua-environment-with-nix-shell}
|
||
|
||
|
||
There are two methods for loading a shell with Lua packages. The first and recommended method
|
||
is to create an environment with `lua.buildEnv` or `lua.withPackages` and load that. E.g.
|
||
|
||
```sh
|
||
$ nix-shell -p 'lua.withPackages(ps: with ps; [ busted luafilesystem ])'
|
||
```
|
||
|
||
opens a shell from which you can launch the interpreter
|
||
|
||
```sh
|
||
[nix-shell:~] lua
|
||
```
|
||
|
||
The other method, which is not recommended, does not create an environment and requires you to list the packages directly,
|
||
|
||
```sh
|
||
$ nix-shell -p lua.pkgs.busted lua.pkgs.luafilesystem
|
||
```
|
||
Again, it is possible to launch the interpreter from the shell.
|
||
The Lua interpreter has the attribute `pkgs` which contains all Lua libraries for that specific interpreter.
|
||
|
||
|
||
## Developing with Lua {#developing-with-lua}
|
||
|
||
Now that you know how to get a working Lua environment with Nix, it is time
|
||
to go forward and start actually developing with Lua. There are two ways to
|
||
package lua software, either it is on luarocks and most of it can be taken care
|
||
of by the luarocks2nix converter or the packaging has to be done manually.
|
||
Let's present the luarocks way first and the manual one in a second time.
|
||
|
||
### Packaging a library on luarocks {#packaging-a-library-on-luarocks}
|
||
|
||
[Luarocks.org](https://luarocks.org/) is the main repository of lua packages.
|
||
The site proposes two types of packages, the `rockspec` and the `src.rock`
|
||
(equivalent of a [rockspec](https://github.com/luarocks/luarocks/wiki/Rockspec-format) but with the source).
|
||
|
||
Luarocks-based packages are generated in [pkgs/development/lua-modules/generated-packages.nix](https://github.com/NixOS/nixpkgs/tree/master/pkgs/development/lua-modules/generated-packages.nix) from
|
||
the whitelist maintainers/scripts/luarocks-packages.csv and updated by running
|
||
the script
|
||
[maintainers/scripts/update-luarocks-packages](https://github.com/NixOS/nixpkgs/tree/master/maintainers/scripts/update-luarocks-packages):
|
||
|
||
```sh
|
||
./maintainers/scripts/update-luarocks-packages update
|
||
```
|
||
|
||
[luarocks2nix](https://github.com/nix-community/luarocks) is a tool capable of generating nix derivations from both rockspec and src.rock (and favors the src.rock).
|
||
The automation only goes so far though and some packages need to be customized.
|
||
These customizations go in [pkgs/development/lua-modules/overrides.nix](https://github.com/NixOS/nixpkgs/tree/master/pkgs/development/lua-modules/overrides.nix).
|
||
For instance if the rockspec defines `external_dependencies`, these need to be manually added to the overrides.nix.
|
||
|
||
You can try converting luarocks packages to nix packages with the command `nix-shell -p luarocks-nix` and then `luarocks nix PKG_NAME`.
|
||
|
||
#### Packaging a library manually {#packaging-a-library-manually}
|
||
|
||
You can develop your package as you usually would, just don't forget to wrap it
|
||
within a `toLuaModule` call, for instance
|
||
|
||
```nix
|
||
mynewlib = toLuaModule ( stdenv.mkDerivation { ... });
|
||
```
|
||
|
||
There is also the `buildLuaPackage` function that can be used when lua modules
|
||
are not packaged for luarocks. You can see a few examples at `pkgs/top-level/lua-packages.nix`.
|
||
|
||
## Lua Reference {#lua-reference}
|
||
|
||
### Lua interpreters {#lua-interpreters}
|
||
|
||
Versions 5.1, 5.2, 5.3 and 5.4 of the lua interpreter are available as
|
||
respectively `lua5_1`, `lua5_2`, `lua5_3` and `lua5_4`. Luajit is available too.
|
||
The Nix expressions for the interpreters can be found in `pkgs/development/interpreters/lua-5`.
|
||
|
||
#### Attributes on lua interpreters packages {#attributes-on-lua-interpreters-packages}
|
||
|
||
Each interpreter has the following attributes:
|
||
|
||
- `interpreter`. Alias for `${pkgs.lua}/bin/lua`.
|
||
- `buildEnv`. Function to build lua interpreter environments with extra packages bundled together. See section *lua.buildEnv function* for usage and documentation.
|
||
- `withPackages`. Simpler interface to `buildEnv`.
|
||
- `pkgs`. Set of Lua packages for that specific interpreter. The package set can be modified by overriding the interpreter and passing `packageOverrides`.
|
||
|
||
#### `buildLuarocksPackage` function {#buildluarockspackage-function}
|
||
|
||
The `buildLuarocksPackage` function is implemented in `pkgs/development/interpreters/lua-5/build-luarocks-package.nix`
|
||
The following is an example:
|
||
```nix
|
||
luaposix = buildLuarocksPackage {
|
||
pname = "luaposix";
|
||
version = "34.0.4-1";
|
||
|
||
src = fetchurl {
|
||
url = "https://raw.githubusercontent.com/rocks-moonscript-org/moonrocks-mirror/master/luaposix-34.0.4-1.src.rock";
|
||
hash = "sha256-4mLJG8n4m6y4Fqd0meUDfsOb9RHSR0qa/KD5KCwrNXs=";
|
||
};
|
||
disabled = (luaOlder "5.1") || (luaAtLeast "5.4");
|
||
propagatedBuildInputs = [ bit32 lua std_normalize ];
|
||
|
||
meta = with lib; {
|
||
homepage = "https://github.com/luaposix/luaposix/";
|
||
description = "Lua bindings for POSIX";
|
||
maintainers = with maintainers; [ vyp lblasc ];
|
||
license.fullName = "MIT/X11";
|
||
};
|
||
};
|
||
```
|
||
|
||
The `buildLuarocksPackage` delegates most tasks to luarocks:
|
||
|
||
* it adds `luarocks` as an unpacker for `src.rock` files (zip files really).
|
||
* `configurePhase` writes a temporary luarocks configuration file which location
|
||
is exported via the environment variable `LUAROCKS_CONFIG`.
|
||
* the `buildPhase` does nothing.
|
||
* `installPhase` calls `luarocks make --deps-mode=none --tree $out` to build and
|
||
install the package
|
||
* In the `postFixup` phase, the `wrapLuaPrograms` bash function is called to
|
||
wrap all programs in the `$out/bin/*` directory to include `$PATH`
|
||
environment variable and add dependent libraries to script's `LUA_PATH` and
|
||
`LUA_CPATH`.
|
||
|
||
By default `meta.platforms` is set to the same value as the interpreter unless overridden otherwise.
|
||
|
||
#### `buildLuaApplication` function {#buildluaapplication-function}
|
||
|
||
The `buildLuaApplication` function is practically the same as `buildLuaPackage`.
|
||
The difference is that `buildLuaPackage` by default prefixes the names of the packages with the version of the interpreter.
|
||
Because with an application we're not interested in multiple version the prefix is dropped.
|
||
|
||
#### lua.withPackages function {#lua.withpackages-function}
|
||
|
||
The `lua.withPackages` takes a function as an argument that is passed the set of lua packages and returns the list of packages to be included in the environment.
|
||
Using the `withPackages` function, the previous example for the luafilesystem environment can be written like this:
|
||
|
||
```nix
|
||
with import <nixpkgs> {};
|
||
|
||
lua.withPackages (ps: [ps.luafilesystem])
|
||
```
|
||
|
||
`withPackages` passes the correct package set for the specific interpreter version as an argument to the function. In the above example, `ps` equals `luaPackages`.
|
||
But you can also easily switch to using `lua5_2`:
|
||
|
||
```nix
|
||
with import <nixpkgs> {};
|
||
|
||
lua5_2.withPackages (ps: [ps.lua])
|
||
```
|
||
|
||
Now, `ps` is set to `lua52Packages`, matching the version of the interpreter.
|
||
|
||
### Possible Todos {#possible-todos}
|
||
|
||
* export/use version specific variables such as `LUA_PATH_5_2`/`LUAROCKS_CONFIG_5_2`
|
||
* let luarocks check for dependencies via exporting the different rocktrees in temporary config
|
||
|
||
### Lua Contributing guidelines {#lua-contributing-guidelines}
|
||
|
||
Following rules should be respected:
|
||
|
||
* Make sure libraries build for all Lua interpreters.
|
||
* Commit names of Lua libraries should reflect that they are Lua libraries, so write for example `luaPackages.luafilesystem: 1.11 -> 1.12`.
|