Concise Object Notation

--Concise Object Notation - SpiderString - TheINCGI
local CON = {}

local function exportObj( file, obj, indent, name )
  indent = indent or 0
  file.write(("  "):rep(indent)..name)
  if type(obj)~="table" then
    file.writeLine((type(name)=="number" and " = " or ": ").. (type(obj)=="string" and ('"'..obj..'"') or tostring(obj)))
  else
    file.writeLine("")
    for k,v in pairs( obj ) do
      exportObj( file, v, indent+1, k )
    end
  end
end

local function importObj( file, out, line, indents )
  if not line then return end
  indents = indents or 0
  local name = line:gsub("^ *",""):gsub(" *$","")
  local t;
  if not name:match"^.+ ?[=:]" then
    t = {}
    out[ name ] = t
    if file.available() <= 0 then return end
    line = file.readLine():gsub(" *$","") --trim end
  else
    t = out
    line = "  "..line
  end
  while line and #line:gmatch(" *")() / 2 == indents + 1 do
    local m = line:match"^ *%w+ ?[:=] "
    if m then --any spaces, var name, and a : space
      local keyIsNum = m:match"^ *-?%w+ =" and true or false
      local pName = line:match"^ *(-?%w+) ?[:=]"
      local v = line:sub(#m+1)
      local s = v:match"^%\"(.+)%\""
      if s then
        v = s
      else
        if v=="true" then
          v = true
        elseif v=="false" then
          v = false
        else
          local n = tonumber(v)
          if not n then error(string.format("Format exception for field '%s' with value '%s'",pName,v)) end
          v = n
        end
      end
      t[ keyIsNum and tonumber(pName) or pName ] = v
      line = file.readLine():gsub(" $","")
    else
      line = importObj( file, t, line, indents+1 )
    end
  end
  return line
end

function CON.import( path )
  local out = {}
  local file = filesystem.open( path, "r" )
  local line = file.readLine()
  while file.available() > 0 do
    line = importObj( file, out, line )
  end
  file.close()
  return out
end

function CON.export( path, obj )
  assert( type(path)=="string", "String path expected, got "..type(path) )
  assert( type(obj)=="table",   "Table expected, got "..type(obj) )

  local file = filesystem.open( path, "w" )
  for k,v in pairs(obj) do
    --if type(v)=="table" then
      exportObj( file, v, 0, k )
    --end
  end
  file.close()
end

local test = {
  x = {
   p={},
    1,2,3
  },
  y = {
    h="i"
  },
  z= {56},
  w= {"ok", toast="most"},
  l=100
}

CON.export( "test.con", test )
log( CON.import( "test.con" ) )