バージョン管理と依存関係管理

return {
  name        = "auth",
  version     = "2.1.0",
  apiRequired = ">=1.0.0",
  deps        = { {name="logger", version=">=1.0.0"} },
  init        = function(app) -- ... end
}

local function parseVersion(v)
  local major, minor, patch = v:match("(%d+)%.(%d+)%.(%d+)")
  return {tonumber(major), tonumber(minor), tonumber(patch)}
end
local function versionGe(a, b)
  a, b = parseVersion(a), parseVersion(b)
  for i = 1, 3 do
    if a[i] ~= b[i] then return a[i] > b[i] end
  end
  return true
end

local APP_VERSION = "1.5.0"
local function checkCompatibility(plugin)
  local req = plugin.apiRequired or ">=0.0.0"
  local minVer = req:match(">=(.+)")
  if minVer and not versionGe(APP_VERSION, minVer) then
    error(("Plugin %s requires app >= %s, got %s"):format(
      plugin.name, minVer, APP_VERSION))
  end
end

local loading = {}
local function loadWithCycleCheck(name, plugins)
  if loading[name] then error("Circular dependency: " .. name) end
  loading[name] = true
  -- load deps then load plugin
  loading[name] = nil
end