Re: minor lua refman grammar points
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- Subject: Re: minor lua refman grammar points
- From: David Manura <dm.lua@...>
- Date: 2011年1月22日 14:26:46 -0500
On Wed, Jan 19, 2011 at 10:29 PM, David Manura <dm.lua@math2.org> wrote:
> Two minor points about the grammar in the Lua Reference Manual:
Another trivial point:
-- http://www.lua.org/manual/5.1/manual.html#2.4.5
for var_1, ···, var_n in explist do block end
is equivalent to the code:
do
local f, s, var = explist
while true do
local var_1, ···, var_n = f(s, var)
var = var_1 --[*]
if var == nil then break end --[*]
block
end
end
In actual implementations, there's no reason to set `var` on break, so
the marked [*] lines are swapped:
if var_1 == nil then break end
var = var_1