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So hang on, would this mean that, as a host app or module writer, I can no
longer rely on this to work:
t = { 1,2,3 }
print(t[2])
-> 2
if some other module or user script has gone and installed a ‘clever’ type
metatable?
I realise this is currently the case with string, but there’s a lot less
incentive to do clever things with that.
Like I said, I like the concept, but I wonder if there is some way this
could be made _ENV bound, or similar, to avoid nasty side-effects in other
modules.
- Claire.
From: John Hind
Sent: Wednesday, December 05, 2012 10:16 PM
Subject: Type Metatables for Table and Userdata -
Powerpatch Please take a look at my new PowerPatch at
http://lua-users.org/wiki/LuaPowerPatches. This allows the Table and Userdata
types to have type metatables without losing their current per-object ones. This
new mechanism is then used to expose the Table Library as methods of Table
objects in the same way the String Library is exposed for String objects.
(Logically, 'pairs', 'ipairs' and 'next' should also be exposed as methods, but
I have not done that in the patch.) For very little cost, this makes Lua more
consistent and also adds a powerful new generalised mechanism for others to
build on. While there, you could maybe take another look at my
'Self-iterating Objects' patch further down the same page. Having used this
extensively myself over the last few years, I am more than ever convinced this
is a worthwhile improvement. No virus found in this
message. |