Hello, all:

I'm having trouble with a simple script I'm writing, and would appreciate some help. I have several different workarounds (see Note), but none of them feel "right", so I'm looking for alternatives.

Here's the script I'm having trouble with:

#!/usr/bin/perl
#
# PM_help.pl FileName - Prints contents of file FileName
# PM_help.pl -test    - Prints contents of <DATA> handle
# PM_help.pl          - Prints contents of STDIN
#
use strict;
use warnings;
use IO::Handle;

# Prepare the selected filehandle

my $FName=shift;
my $FH = new IO::Handle;
if (! defined $FName) {
    $FH->fdopen(fileno(STDIN), "r")
      or die "Can't grab STDIN!\nErrMsg: $!\n";
}
elsif ($FName eq "-test") {
    # I was hoping one of these two would work, but no luck
    #$FH->fdopen(fileno(DATA), "r")
    #  or die "Can't grab DATA!\nErrMsg: $!\n";
    #$FH->new_from_fd(fileno(DATA), "r")
    #  or die "Can't grab DATA!\nErrMsg: $!\n";

    # Works, but I don't care for it
    open $FH, '<', $0
      or die "Can't open '$0'\nErrMsg: $!\n";
    while (<$FH>) {
        last if /^__DATA__\s*$/;
    }
}
else {
    open $FH, '<', $FName
      or die "Can't open '$FName'\nErrMsg: $!\n";
}

# Use the file...

while (<$FH>) {
        print "$.: $_";
}

# EXAMPLE DATA
__DATA__
The quick red fox jumped over the lazy brown dog.
Now is the time for all good men to come to the aid of their party.
[download]

The gist of it is, after reading open, perlopentut and IO::Handle, I can't figure out how to grab the <DATA> handle and put it into $FH as I do with the STDIN handle. While I can do it, I feel that there's a better way.

Why do I care?
I usually keep a set of test data with my scripts so I can easily test them, or use them as example input to refresh my memory when I forget the details. But I don't like having to keep track of the data file along with the script when I move it around, pass it to friends, etc. So I'm trying to adopt the practice of putting the test data in the __DATA__ section at the end of the file. Ultimately, I plan on taking the open logic section and putting it into a subroutine that I can place in my ROBO::Utils module.

Note: I've tried:

• Opening $0 and skipping to the __DATA__ section (currently the "best"),
• Using if/then/else statements to select the appropriate filehandle as needed, and
• Putting the if/then/else statements in a subroutine to make it more convenient to use.

However, I can't help but feel that I should be able to redirect the <DATA> filehandle similar to the <STDIN> filehandle, but I just don't know the proper incantation. If no-one can find something better, I'll use what I have.

Thanks in advance!

...roboticus

When your only tool is a hammer, all problems look like your thumb.

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