Reading a file on Lua

Question

I'm working on a Lua project for college, but this is the first time I'm seeing Lua, so I don't know everything my teachers asked me to do.

I need to read a file, we must say "text.txt", which its data are organized this way:

entry
{
--
name = "John",
--
sex = "M" ou "F",
--
age = 20,
--
}

Then I need to put this data in an array so I can use them later.

Does anyone know how to do it and can help me with this code?

Answer 1

This format is a subset of Lua syntax, so you should have a fairly easy time of parsing it, assuming you're allowed to use some library functions.

As far as the format of the file goes: f{ ...} is syntactic sugar for f({...} as a function call. The rest of the stuff in the braces is comments (starting with --) and table fields (age = 20,)

So, for instance, the example above (with "M" where we had a choice) would parse as the function call entry({name = "John", sex = "M", age = 20}) which is valid Lua code, and can be parsed with the functions load(string) or loadfile(path in the standard library.

---

To actually extract the data, you'll need to do something along these lines:

local filecontents = [the contents of your file as a string]
local entries = {}
do
  -- define a function that our data-as-code will call with its table
  -- its job will be to simply add the table it gets to our array. 
  local function entry(entrydata)
    table.insert(entries, entrydata)
  end

  -- load our data as Lua code
  local thunk = load(filecontents, nil, nil, {entry = entry})
  thunk()


end