Re: Self-awareness of functions?
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- Subject: Re: Self-awareness of functions?
- From: Luis Carvalho <lexcarvalho@...>
- Date: 2010年12月29日 10:41:07 -0500
> In Lua you must take care if you want to define a global recursive
> function. Thus:
>
> do local fact
> fact = function(x) if x<2 then return 1 else return x*fact(x-1) end end
> fac = fact
> end
> fact = "Napoleon escaped from Elba."
> print(fac(5)) --> 120
>
> You can't omit any of that padding: create a local variable, then
> assign it to a global variable, all in an enclosing block.
>
> Because of the need for a local name for the function, you can't define
> an anonymous recursive function, e.g. for use in an argument list.
>
> A standard name like "self" which makes the function aware of itself,
> would be useful:
<snip>
What about this?
fact = function (n)
if n < 2 then return 1 end
local self = debug.getinfo(1, "f").func
return n * self(n - 1)
end
Cheers,
Luis
--
Computers are useless. They can only give you answers.
-- Pablo Picasso
--
Luis Carvalho (Kozure)
lua -e 'print((("lexcarvalho@NO.gmail.SPAM.com"):gsub("(%u+%.)","")))'