`require()` semantics?
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- Subject: `require()` semantics?
- From: Pierre-Yves Gérardy <pygy79@...>
- Date: 2014年6月24日 23:49:01 +0200
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