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- Subject: Re: multiple assignement clarification
- From: Jamie Webb <j@...>
- Date: Sun, 25 Sep 2005 17:19:53 +0100
On Sun, Sep 25, 2005 at 06:00:38PM +0200, Enrico Tassi wrote:
> What should we expect from this code?
> x = 1
> function f()
> x = x + 1
> return x
> a,b,a = f(), f(), f()
> I checked a bit the Lua 5.0.2 manual and there is no clarification,
> except for the fact that f() is called 3 times.
> The result of the execution is 2,3,4.
> I think there are 2 possibilities:
> - after the f() calculation assignments are performed from the right
> to the left
> - assignments are performed from the left to the right but there is a
> check for duplicate variable name
> I guess the first.
Yes. The assignments are made in the order the values are popped off
> In any case... isn't this a good place to generate an error? Is this
> check considered too heavy or not so interesting?
Consider the idiom
local _,_,foo = lots_of_results()
The _ is not special in Lua; it's just used for garbage by convention.
-- Jamie Webb