[Swift-user] output file array

[Mihael Hategan]

Hi Ketan,

On Fri, 2015-01-09 at 11:17 -0600, Ketan Maheshwari wrote:
[...]
> >
> > Not automagically! You pass the stdout/stderr file names to the app
> > command line using stdout= and stderr=.
> >
> 
> True. However, the scheme is not quite consistent due to the following
> behavior:
> 
> -- When specifying stdout and stderr in command line, I do not specify them
> in directories. Yet, if I map them in non-existent directories, Swift will
> create those directories and put the stdout/stderr files in them. This does
> not happen with other files even if they are specified in command line.

I do not think that is true. Swift creates directory structures for all
input and output files, whether they are specified on the command line
or not. If this isn't working, then we are talking about a bug, but the
code was designed to do this from the start. I did a quick check and it
seems to work fine for both 0.95 and trunk.

> 
> -- If a file is specified as output file in app definition but does not
> appear in the command line, Swift will still bring it in as an output.
> Again, this will happen only if the file is mapped at top level and not in
> any directory.

I do not believe that to be true either. Swift stages in all files that
are parameters to and app and stages out all files that are returns from
an app. There is no code to treat files differently based on whether
they are in sub-directories or not. Again, if this isn't working on a
specific version of the code, we may be looking at a bug. I checked
this, too, and it works on 0.95 and trunk with the simple configurations
I tried.

> 
> >
> > So in all cases swift honors what you tell it to honor. The question is
> > what is it that you really want here:
> > - is it to automatically create multiple versions of files when an app
> > specifies the same output file and there are multiple invocations?
> >
> 
> Yes. The app specifies it alright but the executable does not specify it on
> command line.

I am not sure how that answers the question above. What I meant was
this:

foreach i in [0:10] {
  file outf <"out.txt">;
  outf = echo(i);
}

where echo(i) is an app that returns a file.

The question was whether you are suggesting that the code above should
be valid code. It is not currently because it violates the local
consistency rule. In other words, writing the equivalent of this in a
shell script will result in out.txt being overwritten, and that results
in nondeterminism based on exactly how the echo() invocations are
ordered.

> > - or is it for swift to ignore the directory in the remote app output
> > when staging out files (but not locally)?

Mihae