Hi,
I think I just found a bug regarding to-be-closed variables. For some
reason the forth to-be-closed variable of a for-in loop has problems to
close with a tailcall as can be seen in the following example.
local function test()
for l in pairs_with_close() --[[io.lines("test.lua")]] do
return tail()
The problem is that 'tail' is no longer a tail call. In the general case the file can only be closed after 'tail' returns, like in this convoluted example:
local f = assert(io.open("/usr/share/dict/words"))
local function read_next()
return f:read("l")
end
for w in read_next, nil, nil, f do
print(w)
if (w == "cheese") then
return tail(f)
end
end
The program reads a dictionary until it finds the word "cheese", then calls a function 'tail' with the file.
(Would I code it like that? No, but it's legal.)
The simpler case:
local function test()
local x <close> = some_object_with_a_close_metamethod()
return tail()
end
Here 'tail' is not a tail call either, because the __close metamethod of 'x' has to be called after 'tail' returns.
