Re^5: how do I "initialize" $

I tested this with my Perl

C:\Users\mmtho\Documents\PerlProjects>perl -v

This is perl 5, version 24, subversion 3 (v5.24.3) built for MSWin32-x
+64-multi-thread
(with 1 registered patch, see perl -V for more detail)

...
[download]

And I found out that Perl has changed how it deals with <DATA>.
This works with Perl 5.24:

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

while (my $line = <DATA>)
{
   print $line;
}


__DATA__
aBC 
XYAS
[download]

Comment on Re^5: how do I "initialize" $_ Select or Download Code

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Re^6: how do I "initialize" $_ by AnomalousMonk (Archbishop) on Oct 13, 2018 at 06:21 UTC
In an oversight since corrected, I neglected to mention that the code here was run under Perl version 5.8.9. I tried `while (my $line = <DATA>) { print $line; }` [download] with my original `__DATA__` both with and without a newline after the 0 on the final line and with strictures and warnings fully enabled and under 5.8.9 and saw no difference in behavior (and no warnings). The reason is easy to see from a deparse: `c:\@Work\Perl\monks\Marshall>perl -MO=Deparse,-p t_read_DATA_2.pl use warnings; use strict 'refs'; print("perl version: $] \n\n"); while (defined((my $line = <DATA>))) { do { print($line) }; } __DATA__ line the first second line penultimate line is line 3 t_read_DATA_2.pl syntax OK 0` [download] The defined test is automatically added. Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]
Re^7: how do I "initialize" $_ by Marshall (Canon) on Oct 13, 2018 at 09:51 UTC
Interesting. In any event apparently defined() on the <DATA> file handle is not needed - or at least not any more. Update: I haven't been able to reproduce this warning on my current Perl 5.24 version. From what I remember the warning was unusually specific in what it said - this was very specific. To my knowledge, I never did actually try Perl code that would cause the problem that was warned about. This was a warning about something that could potentially happen - not an error. This situation did not occur in my source code. I just took Perl at "its word" and adjusted my source code so that this warning went away. I think of Perl as a living, breathing, biological organism that evolves over time. It is completely possible that this was an extraneous warning about something that didn't really matter. At this point, I don't know. It could be that this warning was just emitted in one version of Perl and corrected in the next version. I've worked with a lot of versions of Perl. I don't have nor would I have saved the exact text of this warning.	[reply]