Re^4: Introspecting the current Perl file via DATA, even w/o DATA? (perl5db.pl)

> Anyway, let us know if you'll find something in perl5db.pl or somewhere else.

see http://cpansearch.perl.org/src/SHAY/perl-5.22.1/lib/perl5db.pl

line 405

=head4 C<@dbline>

Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
supplied by the Perl interpreter to the debugger. Contains the source.
[download]

and line 176

=head1 DATA STRUCTURES MAINTAINED BY CORE

There are a number of special data structures provided to the debugger
+ by
the Perl interpreter.

The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline>
via glob assignment) contains the text from C<$filename>, with each
element corresponding to a single line of C<$filename>.
[download]

Seems to be magic. Dunno if it depends on debug flags or just the context of the DB package like other magic (e.g. @DB::args )

Anyway, let us know if you'll find something details about that magic. ;-).

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)

Je suis Charlie!}

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Re^5: Introsepcting the current Perl file via DATA, even w/o DATA? (perl5db.pl) by Anonymous Monk on Feb 05, 2016 at 16:11 UTC
Anyway, let us know if you'll find something details about that magic. ;-) You're so lazy, LanX ;) I'm sure you could do it yourself, but if you insist... `# main.pl BEGIN { $^P = 0x400; } use test ();` [download] and `# test.pm my @source = @{ $main::{ '_<' . __FILE__ } }; print for @source; 1;` [download] Now, the thing is, you have to set `$^P` before the file (test.pm in this case) is even opened. So you can't do it inside test.pm itself, I don't think... Is that good enough for you?	[reply] [d/l] [select]
Re^6: Introsepcting the current Perl file via DATA, even w/o DATA? (perl5db.pl) by Mr. Muskrat (Canon) on Feb 05, 2016 at 16:37 UTC
I found this interesting so I played with it briefly... `# main.pl my @source = @{ $main::{ '_<' . __FILE__ } }; shift @source; # get rid of sub DB::DB{}; print for @source;` [download] and `PERL5DB="sub DB::DB{}" perl -d main.pl` [download] Output: `my @source = @{ $main::{ '_<' . __FILE__ } }; shift @source; # get rid of sub DB::DB{}; print for @source;` [download] Update: I had found @{$main::{'_<'.$filename}} yesterday but didn't have time to play with it. Update 2: Added shift.	[reply] [d/l] [select]
Re^7: Introspecting the current Perl file via DATA, even w/o DATA? (perl5db.pl) by LanX (Saint) on Feb 05, 2016 at 17:05 UTC
> Added shift. as a side note: line numbers start with 1, so changing the content of the 0th element may be the better strategy. ( Otherwise looking up a line will include a cumbersome -1 operation.) Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Je suis Charlie!}	[reply]
Re^6: Introspecting the current Perl file via DATA, even w/o DATA? (perl5db.pl) by LanX (Saint) on Feb 05, 2016 at 16:19 UTC
> Is that good enough for you? yes, I knew I can count on your collaboration! ;) > Now, the thing is, you have to set `$^P` before the file (test.pm in this case) is even opened. I think one could trick that², the question is rather about other penalties included. ... let's have a look into perlvar#$^P ... `x400 Save source code lines into @{"_<$filename"} .` [download] OK this doesn't look to expensive ... benchmark needed. (too busy now ;-) Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Je suis Charlie!} footnotes ²) for instance IIRC it's possible to configure global setting for your perl interpreter.	[reply] [d/l] [select]


The stupid question is the question not asked
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Re^4: Introspecting the current Perl file via DATA, even w/o DATA? (perl5db.pl)

footnotes