(2024-11)

Command-line tool to aggregate all *.lua files in current directory (and subdirectories) into one.

Okay guys, our use case is some multi-file Lua project. At the end we want to see one Lua file which can be distributed independently.

• Actually I have some test "project" at test_case. Won't lose time typing about it.

• $ lua_code_melder/test_case$ lua test.lua
  > [Test representation.]
  

  Okay, looks legit.
• I'll go straight to "correct" commands. I encourage you to experiment with more obvious ways and understand what they do. Note the directory names to reproduce it.
• Melding the melder

  $ lua_code_melder/src$ lua meld.lua meld > ../ingots/meld.lua
  

• Melding the test project

  $ lua_code_melder/test_case$ lua ../ingots/meld.lua test > ../ingots/test.lua
  

• Test run of melded test project

  lua_code_melder/ingots$ lua test.lua
  [Test representation.]
  

  Still looks legit.

• Melding the melded melder and melded test project

  $ lua_code_melder/ingots$ lua meld.lua > ../alloy.lua
  

• Running "test" part of alloy

  $ lua_code_melder$ lua alloy.lua test
  > [Test representation.]
  

• Running "melder" part of alloy

  $ lua_code_melder$ lua alloy.lua meld
  > [... lots of Lua code lines ...]
  

Melder generates Lua source code and prints it to stdout.

It is a file scanner. It gets all *.lua files from current dir, converts their file names to module names and loads their text (source code).

It writes them to table

local Modules = {
  <ModuleName> = ModuleCode
}

Then it compiles their code but not runs it. Compiled code is stored in _G.package.preload table (see Lua documentation). Hat tip from me to Lua authors for this nice design.

local AddModule =
  function(Name, Code)
    local CompiledCode = assert(load(Code, Name, 't'))

    _G.package.preload[Name] =
      function(...)
        return CompiledCode(...)
      end
  end

for ModuleName, ModuleCode in pairs(Modules) do
  AddModule(ModuleName, ModuleCode)
end

And finally it adds activation line, which is a mere require(<module_name>).

<module_name> is that additional command-line argument: test or meld in our examples.

If there is no command-line argument, activation line is require(arg[1]). Yep. Call any module from library from command-line.

Sapienti sat.

• Lua 5.4
• Linux
• Binutils (find)

As usually all needed guts from [workshop] are included in this repo. You can just copy melder and not clone repo at all.

• My other repositories