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- Subject: Re: [manual] chaining metamethods
- From: Coda Highland <chighland@...>
- Date: Wed, 27 Jan 2016 10:35:24 -0800
On Wed, Jan 27, 2016 at 10:27 AM, Dirk Laurie <firstname.lastname@example.org> wrote:
> 2016-01-27 19:04 GMT+02:00 Stephan Hennig <email@example.com>:
>> Note that queries for metamethods are always raw; when
>> looking-up metamethods, Lua doesn't consider a metatable's
>> metatable. Lua considers metatables of metamethods, though.
>> In fact, chaining metamethods is at the heart of many
>> approaches to object-oriented programming in Lua.
> Sorry, I find this more obscure than the original one-sentence
>> Note that queries for metamethods are always raw; the access
>> to a metamethod does not invoke other metamethods.
> I read this as "if the metatable does not contain for example
> __add, the __index metamethod is not invoked to find
> a fallback, eic." What other way is there of reading it?
It could also be read (erroneously) as "y = x.__add will always be
raw". At the very least it could be said that built-in operations will
always look up metamethods using raw access or something like that.