joker0927 has asked for the wisdom of the Perl Monks concerning the following question:

OK, I'm a newbie; so please don't laugh too loud or flame me here, but this one is driving me crazy.

The goal here is to be able to pass /? to my perl app as a command line arg and have it return the text that follows __DATA__. To save space, I've only listed the pertinent code. And yes, I've tested this portion only with the same results.

The following code works: 
use strict;
package SAR;

&get_args (@ARGV);

sub get_args {
    my @help = <DATA>;
    ($ARGV[0] eq "/?") && (die @help);
}

return 1;

__DATA__

testing 1
testing 2
testing 3

[download]
When ran as c:>test.pl /?
It returns:

testing 1
testing 2
testing 3

as expected.

However, after turning it into an exe with perlapp it no longer works. Running c:>test.exe /? will return "Died at test.pl line 8." unless I wrap the @help array in quotes, then it just returns a few blank lines and goes back to the prompt.
I've tried including the package (i.e. SAR::DATA) thinking it might have something to do with the fact that perlapp is adding a lot of other modules and maybe it's getting confused about which module to pull DATA from, but that didn't work. It gives the same results.

I promise I've done my homework. I searched this website, activestates documentation, perldoc, and several books on perl. I just can't find an answer anywhere. Any insight here would be greatly appreciated.

Replies are listed 'Best First'.
Re: perlapp, die, and __DATA__
by grep (Monsignor) on Apr 25, 2003 at 04:36 UTC
    You can't use the <DATA> filehandle with perlapp.

    Also couple of comments on your code: 

    use strict;
package SAR;    

&get_args (@ARGV);   #Ok here you're passing a copy 
                     #of @ARGV into get_args's @_.
                     #BTW your don't need & the
                     #trailing ()'s make strict happy

sub get_args {
    my @help = <DATA>;   #Why read this now
                         #You don't know if you need
                         #it yet.

    ($ARGV[0] eq "/?") && (die @help);
                         #Ok you passed the contents of
                         #@ARGV into your sub in @_ but 
                         #you ignore it and read the 
                         #global @ARGV directly.
                         #copy @_ that way you don't have
                         #to worry about modifing the 
                         #global @ARGV.
    #my @array = @_;
    #die @help if ($array[0] eq "/?")
}

    [download]
    UPDATE: integral is absolutely right, and I'm in a case of do what I mean not what I say :(. Updated comment to correct.

    grep
    Mynd you, mønk bites Kan be pretti nasti...
[reply]
[d/l]
[select]

      Perl passes by alias, so using @_ instead of @ARGV will not prevent worries about modifying the global @ARGV. Options are to make a lexical copy (my @args = @ARGV) or to localise (local @ARGV = @ARGV).

      use strict;
use warnings;
print "1: @ARGV\n";
foo(@ARGV);
print "3: @ARGV\n";
sub foo {
  print "2a: @_\n";
  $_[0] = "foobar";
  print "2b: @_\n";
}

      [download]

      (Note however that the elements are aliased indivualluy into @_ not the whole array, so if @ARGV is empty there will be no modification as you are then adding a new element to @_ instead of modifying an element in @ARGV through @_.)

      --
integral, resident of freenode's #perl
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[d/l]
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Re: perlapp, die, and __DATA__
by JamesNC (Chaplain) on Apr 25, 2003 at 08:54 UTC
    I wanted to let you know that __DATA__ doesn't work in Tinyperl either. Your code isn't broke... You can create a data file and load it into your app, or just roll your own array to simulate __DATA__ like so... 
    my @DATA;

my @data = q(
testing 1
testing 2
testing 3
);

for (@data) {
push @DATA, split /\n/;
}

$DATA[$_].="\n" for 0..$#DATA;

for(@DATA){
chomp;
print;
}

    [download]

    it's all about preference :) Lot of ways to do the same thing.. James
[reply]
[d/l]

      Or since @DATA isn't needed as an array this would be sufficient:

      my $data = q{
line 1
line 2
line 3
};
# OR
$data = <<'END';
line 1
line 2
line 3
END

# to ensure a terminating newline
# chomp $data; $data .= $/

print "$data";

      [download]

      This is as usual another way to write the first suggestion (where @data should be $data too):

      @DATA = map "$_\n", split /\n/, $data; # but why add \n when you chomp
+ later?

      [download]
       

      --
integral, resident of freenode's #perl
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[d/l]
[select]
Re: perlapp, die, and __DATA__
by Anonymous Monk on Apr 25, 2003 at 04:48 UTC
    OK, I'm a newbie; so please don't laugh too loud or flame me here, but this one is driving me crazy

    Nobody really cares if you're a newbies, we are not here to flame, so no need to draw attention that way.

    Have you read the perlapp documentation? I'm sure it will tell you that this doesn't work.

[reply]
Re: perlapp, die, and __DATA__
by joker0927 (Novice) on Apr 25, 2003 at 17:59 UTC
    Thank you all for the feedback. I actually found that mention in the perlapp faq right after I posted this. I'm glad I posted though. You monks have given me some good perls of wisdom. Thanks.
[reply]

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