OOP and modules
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- Subject: OOP and modules
- From: David Haley <dchaley@...>
- Date: 2006年3月10日 19:12:16 -0800
Hi list,
I've been converting some code to a proper package structure. Since it's
still 5.0.2 code, I'm using the compat-5.1 code which has been working
beautifully.
Previously, when defining a class, I would do something like this:
ParseTree = {}
function ParseTree:new(name, transitionRecord)
local o = {}
setmetatable(o, self)
self.__index = self
return o
end
which is, IIRC, the technique given in PIL to implement classes.
But with modules, this all becomes tedious. I'd have to do something like:
require ("clip.parsetree")
parsetree = clip.parsetree.ParseTree:new()
which seems a bit excessive to me.
My solution is to do the following:
module ("clip.parsetree")
function _M:new(name, transitionRecord)
assert( self == _M, format("You need to call %s:new(), not
%s.new()!", _NAME, _NAME ) )
-- normal stuff follows as above...
end
This seems to work, and I can now do:
require ("clip.parsetree")
parsetree = clip.parsetree:new()
which is what I wanted.
Is this the "right" way of implementing classes in modules? Is there a
better way? Is there something wrong with this approach that I should be
aware of?
Thanks much.
Best,
David
--
~David-Haley
http://david.the-haleys.org