Re: `require()` semantics?

[Pierre-Yves Gérardy <pygy79@...>]

I already spotted a bug:

-            if loader == nil then
+            if type(loader) ~= "function" then
—Pierre-Yves


On Tue, Jun 24, 2014 at 11:49 PM, Pierre-Yves Gérardy <pygy79@gmail.com> wrote:
> I've adapted the simplifed `require()` found in PiL 2nd ed. to
> hopefully match the C implementation (beside the stack trace that
> starts one level deeper).
>
> It works around an "yield across C boundary" issue when using the
> MoonScript loader with OpenResty. The first resumes a coroutine at
> parse time, and the latter runs request handlers in coroutines.
> Requiring a MoonScript file from a handler breaks because of this,
> since `require()` is a C function.
>
> I plan to release it as a Rock and want to make sure it is correct.
>
> For Lua 5.1:
>
>     -- package and package.loaded are cached, while package.loaders isn't.
>     local package, p_loaded = package, package.loaded
>
>     function require (name)
>         if not p_loaded[name] then
>             local msg = {}
>             local loader
>             for _, searcher in ipairs(package.loaders) do
>                 loader = searcher(name)
>                 if type(loader) == "function" then break end
>                 if type(loader) == "string" then
>                     -- `loader` is actually an error message
>                     msg[#msg + 1] = loader
>                 end
>             end
>             if loader == nil then
>                 error("module '" .. name .. "' not
> found:"..table.concat(msg), 2)
>             end
>             p_loaded[name] = true
>             local res = loader(name)
>             if res ~= nil then
>                 p_loaded[name] = res
>             end
>         end
>         return p_loaded[name]
>     end
>
> While I'm at it, is it correct for Lua 5.2?
>
> -            local loader
> +            local loader, param
> -              loader = searcher(name)
> +              loader, param = searcher(name)
> -          local res = loader(name)
> +          local res = loader(name, param)
>
> Thanks in advance :-)
>
> —Pierre-Yves