Am 13.10.2016 um 21:28 schröbte Soni L.:
For two, Lua's module system fully supports relative requires. This is
one of the most overlooked features of Lua! I see people doing `local
submod = require "thismod.submod"` all the time. That's not how you
do it!
The proper way to do relative requires is:
thismod/init.lua
-----
local modname = ...
local submod = require(modname .. ".submod")
return {submod=submod}
-----
thismod/submod.lua
-----
return {
helloworld = function() print("Hello World!") end
}
-----
Then, if you require "thismod", you can call
thismod.submod.helloworld(). However, if you rename the thismod
directory, and require the new directory name, it'll still work! Unlike
when using hardcoded module names.
I think relative `require` is an anti-pattern for the following reasons:
1. The module name is part of the public interface, so you shouldn't
rename it at all (or at least bump the major version number afterwards).
2. If you move a module `a.x` to `a.s.x`, all relative `require`s in
this module *and of* this module break. With absolute `require` only
the `require`s *of* this module need to be fixed.
3. It only works for internal modules that are never `require`d from
the outside or else the renaming feature stops working anyway.
4. It leads to bloat. For modules like
return { -- file a.lua
b = require( ... .. ".b" ),
c = require( ... .. ".c" ),
-- ...
}
`local a = require("a")` will load all submodules even if only a
few of those modules are actually needed.
5. The interface gets uglier as well:
local a = require( "a" )
a.b.u.x.func()
compared to
local x = require( "a.b.u.x" )
x.func()
6. You can run into `require` cycles if module `a.b.u.x` needs
functions from module `a.b` but should also be part of it.
Philipp
