Re: Metatables for functions

[Mark Hamburg <mark@...>]

On Mar 24, 2009, at 6:00 PM, Luiz Henrique de Figueiredo wrote:

> > Is there any reason not to support metatables for functions?
>
> There is support for metatables for function, only not from Lua,  
> just from C.
> Or you can use debug.setmetatable. See the example below.
>
> debug.setmetatable(print,{
> 	__add = function(f,g) return function (...) return g(f(...)) end  
> end})
>
> function f(x) return x+1 end
> function g(x) return x^2 end
>
> h=f+g assert(h(2)==9)
> h=g+f assert(h(2)==5)

Yes, but that applies the same metatable to all functions. I should  
perhaps have been more precise and said "per function  
metatables" (defaulting back to a shared metatable for compatibility).

Mark