Re: Operators on functions
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- Subject: Re: Operators on functions
- From: "Pierre Chapuis" <catwell@...>
- Date: 2013年11月20日 16:45:58 +0100
> On Wed, Nov 20, 2013 at 3:49 PM, Pierre Chapuis <catwell@archlinux.us>
> wrote:
> It actually _is_ very straightforward code, just with different
> syntax. There's a lot of sugar going on here! And all this extra
> syntax and rules-for-sugar means, yes, it can blow up.
Maybe we don't have the same definition of straightforward :)
This is a Lua equivalent:
local auto_table = function(fn)
return setmetatable({},{
__index = function(self, name)
local result = fn()
getmetatable(self).__index = result
return result[name]
end
})
end
So: it is a function that takes a closure (fn). It returns an empty table
with a metatable with the __index metamethod set. When the table is
indexed, the metamethod is called.
What's weird is that when called, the __index metamethod calls the closure
and replaces *itself* with the result of that call! Too much meta magic
for me :)
--
Pierre Chapuis