Re: Lua 5.4.0-alpha-rc1 behavior with closing methods errors

[Sergey Kovalev <kovserg33@...>]

This code https://pastebin.com/sEK9GJ9y

вт, 25 июн. 2019 г. в 20:49, Sergey Kovalev <kovserg33@gmail.com>:
>
> Can this code solve auto close problem https://pastebin.com/LPxHKKp8
>
> -- helper function
>
> function scope(self)
>     local result
>     self=self or {}
>     self.list={}
>     self.error=self.error or error
>     local function auto(arg,close,msg)
>         if arg then
>             table.insert(self.list,{ arg=arg, fn=close or io.close })
>         else
>             self.error(msg or "init error",2)
>         end
>         return arg
>     end
>     if self.init then self.init(auto) end
>     local ok,err=pcall(function() result=table.pack(self.body()) end)
>     if self.done then self.done(ok,err) end
>     for _,close in pairs(self.list) do close.fn(close.arg) end
>     if not ok then self.error(err) end
>     return table.unpack(result)
> end
>
> -- usage:
>
> function test()
>     local src,dst
>     scope {
>         init=function(auto)
>             src=auto(io.open("file1.txt","w"))
>             dst=auto(io.open("file2.txt","w"),function(f) print "close
> file" f:close() end )
>         end,
>         body=function()
>             src:write "hello"
>             dst:write "world"
>         end,
>     }
> end
>
> test()
>
> вт, 25 июн. 2019 г. в 20:31, Francisco Olarte <folarte@peoplecall.com>:
> >
> > Sergey:
> >
> > On Tue, Jun 25, 2019 at 6:25 PM Sergey Kovalev <kovserg33@gmail.com> wrote:
> > > __unreference should call immediately when reference count to zero,
> > > unliket __gc it is called latter then there is no way to stand more or
> > > when explicitly call collectgarbage()
> >
> > Lua does not work by reference count.
> >
> > OTOH, <toclose> is really handy to implement your own ref-count
> > schemes, I'm planning to use it for that if I ever switchto 5.4.
> >
> > Francisco Olarte.
> >