如何读取具有多个表的 .lua 文件？

Question

Hello I have never used Lua before and just wanted to simply take a .lua file, parse it, and turn it into some json. I was able to do so with a file with a single table like so:

return { ["Thing"] = { ["SubThing"] = {} } }

What I am struggling to figure out is how to parse a .lua file that has multiple tables defined (I think?). Instead of having a single return, it looks like:

SomeVariable = { ["Thing1"] = { ["SubThing"] = {} } }
SomeOtherVariable = { ["Thing2"] = { ["SubThing2"] = {} } }
SomeLastVariable = { ["Thing3"] = { ["SubThing3"] = {} } }

Since the json library I am using requires a single table to parse, I'm not sure what to do. Any help would be greatly appreciated.

My end goal is to parse that file and have those three variables just be the top level keys of a hash.

Answer 1

Old_G = {}
for k, v in pairs(_G) do
   Old_G[k] = v
end

dofile('file_name.lua')
--SomeVariable = { ["Thing1"] = { ["SubThing"] = {} } }
--SomeOtherVariable = { ["Thing2"] = { ["SubThing2"] = {} } }
--SomeLastVariable = { ["Thing3"] = { ["SubThing3"] = {} } }


local new_keys = {}
for k, v in pairs(_G) do
   if Old_G[k] ~= v then
      new_keys[k] = v
   end
end
Old_G = nil
return new_keys

Answer 2

If this is a separate file, you can do the following:

local json = require 'cjson'
-- Using cjson because it's the one I know, I assume your library is similar

local env = setmetatable({}, {__index=_G})
-- Create a new "env" table that will look up missing keys in the global environment

loadfile(
   "tables.lua", -- Your file
   "t", -- Only read Lua source file, no bytecode
   env -- Load the code with "env" as its environment
)() -- Run the code right after loading it

print(json.encode(env))