Lua

The Lua build-system is a helper for the common case of Lua packages that provide a rockspec file. This is not meant to take a rock archive, but to build a source archive or repository that provides a rockspec, which should cover most lua packages. In the case a Lua package builds by Make rather than luarocks, prefer MakefilePackage.

Phases

The LuaBuilder and LuaPackage` base classes come with the following phases:

  1. unpack - if using a rock, unpacks the rock and moves into the source directory

  2. preprocess - adjust sources or rockspec to fix build

  3. install - install the project

By default, these phases run:

# If the archive is a source rock
$ luarocks unpack <archive>.src.rock
$ # preprocess is a noop by default
$ luarocks make <name>.rockspec

Any of these phases can be overridden in your package as necessary.

Important files

Packages that use the Lua/LuaRocks build system can be identified by the presence of a *.rockspec file in their sourcetree, or can be fetched as a source rock archive (.src.rock). This file declares things like build instructions and dependencies, the .src.rock also contains all code.

It is common for the rockspec file to list the lua version required in a dependency. The LuaPackage class adds appropriate dependencies on a Lua implementation, but it is a good idea to specify the version required with a depends_on statement. The block normally will be a table definition like this:

dependencies = {
   "lua >= 5.1",
}

The LuaPackage class supports source repositories and archives containing a rockspec and directly downloading source rock files. It does not support downloading dependencies listed inside a rockspec, and thus does not support directly downloading a rockspec as an archive.

Build system dependencies

All base dependencies are added by the build system, but LuaRocks is run to avoid downloading extra Lua dependencies during build. If the package needs Lua libraries outside the standard set, they should be added as dependencies.

To specify a Lua version constraint but allow all lua implementations, prefer to use depends_on("lua-lang@5.1:5.1.99") to express any 5.1 compatible version. If the package requires LuaJit rather than Lua, a depends_on("luajit") should be used to ensure a LuaJit distribution is used instead of the Lua interpreter. Alternately, if only interpreted Lua will work depends_on("lua") will express that.

Passing arguments to luarocks make

If you need to pass any arguments to the luarocks make call, you can override the luarocks_args method like so:

def luarocks_args(self):
    return ["flag1", "flag2"]

One common use of this is to override warnings or flags for newer compilers, as in:

def luarocks_args(self):
    return ["CFLAGS='-Wno-error=implicit-function-declaration'"]

External documentation

For more information on the LuaRocks build system, see: https://luarocks.org/