in reply to Printing to stdout an array of strings and scalar references

Hi Anonymous Monk,

I am not sure if this fits into what you're trying to do, but why not simplify the matter by building the output where and when you need it: 

$ perl -e '#!/usr/bin/perl
> use warnings;
> use strict;
>
> my $count = 42;
> my $completed = 6;
>
> notify_progress();
> $completed = 7;
> notify_progress();
>
> sub notify_progress {
>     my $progress_output = ["\rProcessing: ", $count, " files to proc
+ess ; ", $completed, " files completed\n"];
>     print @$progress_output;
> }'
Processing: 42 files to process ; 6 files completed
Processing: 42 files to process ; 7 files completed

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Or even simplify further the notify_progress subroutine: 
$ perl -e '#!/usr/bin/perl
> use warnings;
> use strict;
>
> my $count = 42;
> my $completed = 6;
>
> notify_progress();
> $completed = 7;
> notify_progress();
>
> sub notify_progress {
>     print "Processing: ",  $count, " files to process ; ", $complete
+d, " files completed\n";
> }'
Processing: 42 files to process ; 6 files completed
Processing: 42 files to process ; 7 files completed

[download]
And, BTW, do yourself and other monks a favor, take the time to register an account. ;-)

Replies are listed 'Best First'.
Re^2: Printing to stdout an array of strings and scalar references
by Anonymous Monk on Oct 25, 2017 at 02:36 UTC

    Hi Laurent_R

    Thanks for the feedback, I had considered building the entire output within the subroutine, however I have a requirement be able to modify the output based on the command line option chosen, for example on one run I may need the progress indication to be 

    Processing: 42 files to process ; 6 files completed

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    then on the next run the verbose switch may be selected so I might need 
    Processing: 42 files to process ; 2 files excluded ; 6 files completed

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    Using the array method I am currently looking at lets me just push the required reporting output into the array as I am processing the CLI options which seemed to me to be more efficient than reprocessing the CLI options every time I need to update the progress indicator.

    Regardless I value the time you have taken to review and make suggestions, Thankyou.

[reply]
[d/l]
[select]
      You are welcome.

      OK, now I understand why you're using an arrayref with references to the counters. Although I guess a simple array with references to the counters would also work.

      An alternative approach would be to build dynamically the output subroutine depending on your input: 

      #!/usr/bin/perl
use warnings;
use strict;

my $verbose = shift // 0;
my $excluded = 2;
my $count = 42;
my $completed = 6;
my $notify_progress = build_output_subroutine(); 

$notify_progress->();
$completed = 7;
$notify_progress->();

sub build_output_subroutine {
    my @out;
    if ($verbose) {
        return sub  { print "Processing: ",  $count, " files to proces
+s ; ", $excluded, " files excluded; ", $completed, " files completed\
+n" };
    } else {
        return sub { print "Processing: ",  $count, " files to process
+ ; ", $completed, " files completed\n" };
    }
}

      [download]
      But, in this context, this probably does not really make things really simpler.
[reply]
[d/l]

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