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On Wed, Jul 3, 2019 at 10:11 AM Sean Conner wrote:
It was thus said that the Great Egor Skriptunoff once stated:
> Another possible situation - you are reading multi-volume archive.
> Only one volume file is opened at any given time.
> To switch a volume, you close the current volume file and open the next
> volume file.
> Single to-be-closed variable is enough to guarantee that the last opened
> volume file will be closed on eviction.

  The following worked:

        for i = 1 , 10 do
          local <toclose> f ="volume.%d",i),"w")

  Only one file is open at a time.  So there is a way to kind of re-use a
closed variable.

  Now, the following kept the files open unil the end:

        local function process(i)
          if i < 10 do
            local <toclose> f ="volume.%d",i),"w")
            return process(i+1)

This is OK while you can organize your code in the following loop:
   while (file_j_exists) do
      j = j + 1

But sometimes the logic is complex enough so that you can't simply write the function "process next file".
It might happen that your code has to be a consumer: it needs switching volumes on-the-fly without interrupting main execution stream.
It's a "producer-consumer problem".