Lua module cache manager for LuaTeX and cousins

lua-module-cache-manager.lua is a Lua initialization script for LuaTeX and cousins that manages a cache for Lua modules. Lua modules are typically loaded from source. This implies parsing them and other steps, which incurs some cost. Lua implementations –including the ones bundled in LuaTeX and LuaJITTeX– internally turn the source code into something called 'bytecode'. Loading bytecode would thus be faster than loading source code, as it would skip a few steps. This system approaches the problem by caching all Lua modules loaded from source as bytecode in a single file that works similarly to LaTeX's aux file.

A bit, ja, although I haven't properly benchmarked it. It can be more than half a second in my machine, which is nice for small documents that are compiled often.

LuaTeX engines understand the --lua option. Pass the script path as its argument:

$  lualatex --interaction=nonstopmode --lua=lua-module-cache-manager.lua -- main.tex

Keep in mind, though, that the Lua initialization script is run every time. You should consider byte-compiling it itself; the command depends on the engine in use:

• LuaTeX:

  $  texluac -s -o lua-module-cache-manager.texluabc -- lua-module-cache-manager.lua
  

• LuaJITTeX:

  $  texluajitc -b lua-module-cache-manager.lua lua-module-cache-manager.texluabc
  

Then:

$  lualatex --interaction=nonstopmode --lua=lua-module-cache-manager.texluabc -- main.tex

Lua initialization scripts have access to the arguments with which the LuaTeX engine was invoked. This script handles a few options:

Pass them to the script as if they were normal LuaTeX options:

$  lualatex --interaction=nonstopmode --lua=lua-module-cache-manager.lua --lua-module-cache-file=main.lmc --lua-module-cache-mode=b --lua-module-cache-manager-verbose -- main.tex

• A "new enough" version of LuaTeX/LuaJITTeX.

It has been tested on: - LuaTeX 0.80, revision 5238 by TeX Live 2015 on Windows. - LuaJITTeX 0.80, revision 5238 by TeX Live 2015 on Windows. - LuaTeX 0.95 by TeX Live 2016 on Windows. - LuaJITTeX 0.95 by TeX Live 2016 on Windows.

• A recent enough installation of the LuaLaTeX infrastructure.

In particular, the LaTeX kernel should include LuaTeX support and the luatexbase package should reflect this change. This all panned out around October 2015. See issue #1 for a description of the problem you would face in case you didn't meet this requirement and a workaround by Henry So.