[Swift-user] Error: Attempted to close nonexistent channel buffers

[Ben Clifford]

On Thu, 13 Sep 2007, Allen, M. David wrote:

> (file headlines) getHeadlines(blog b) {
>         app {
>                 feeder @b.feedURL stdout=@filename(headlines);
>         }
> }

probably unrelated, but b.feedURL is a string not a file, so you should 
probably say "b.feedURL" rather than "@b.feedURL" - that will pass the 
feedURL string as a parameter to the feeder program.

@foo means the same as @filename(foo) which only makes sense when foo is a 
file.


> (string matches) findSingleMatch(file input, string searchTerm) {
>         app {
>                 grep "-i" searchTerm @filename(input) stdout=@matches;
>         }
> }

more of a problem is here: data in Swift is either 'in memory' - like ints 
or strings or floats, or 'in files' - you can't really mix the two.

The stdout=@matches line treats matches as a file, but then later on you 
treat it as an 'in memory' value. That is not allowed.

> (file matches) findMatches(file inputs[], string searchTerm) {
>         string final;
>  
>         foreach input, index in inputs {
>                 string intermed = findSingleMatch(input, searchTerm);
>                 final = strcat(final, intermed);
>         }
>  
>         matches = dumpString(final);
> }

Another problem here is trying to assemble the values into a final 
collection in the way you are trying to.

Here's a program which does similar, but using only files, rather than 
swiftscript in-memory values:

type messagefile;

(messagefile t) greeting(string s) {.
    app {
        echo s stdout=@filename(t);
    }
}

(messagefile o) join(messagefile s[]) {
  app {
    cat @filenames(s) stdout=@o;
  }
}

messagefile outfile <"001-echo.out">;
messagefile qqqfile <"b001-echo.out">;

outfile = greeting("monkeys");
qqqfile = greeting("monkeys22");

messagefile everything <"output.txt">;

everything = join([outfile, qqqfile]);

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