Hi

motivation

An old trick is that when seeking the DATA filehandle to the beginning it's possible to read the sourcecode even before __DATA__ starts.

But with source in multiple files, modules and packages this becomes hairy.

approach

I was looking for a possibility to grab the source right away when its parsed.

Thats why I extended this example code from Attribute::Handlers to access DATA when CHECKing and print the line of the sub foo1() declaration:

package LoudDecl;
use Attribute::Handlers;
no warnings;
sub Loud :ATTR {
  my ($package, $symbol, $referent, $attr, $data, $phase, $filename
      , $linenum) = @_;
  print STDERR
    ref($referent), " ",
      *{$symbol}{NAME}, " ",
    "($referent) ", "was just declared ",
      "and ascribed the ${attr} attribute ",
        "with data ($data)\n",
          "in phase $phase\n",
        "in file $filename at line $linenum\n";
  
  my $tell=tell DATA;
  seek DATA,0,0;
  
  while (<DATA>) {print "> $_" if $.==$linenum  };
  seek DATA,$tell,0;
}
  
sub foo1 :Loud {print "HAHA"};
  
__DATA__
  
huhu

[download]

problem

well it works but I get a weird error from Attribut::Handlers, which only goes away after commenting out the while(<DATA>) line. I'm confused...

OUTPUT 

 CODE foo1 (CODE(0x8eba020)) was just declared and ascribed the Loud a
+ttribute with data ()
in phase CHECK
in file /home/lanx/perl/exp/tell.pl at line 23
> sub foo1 :Loud {print "HAHA"};
Can't use an undefined value as an ARRAY reference at /usr/share/perl/
+5.10/Attribute/Handlers.pm line 185, <DATA> line 31.
INIT failed--call queue aborted, <DATA> line 31.
Can't use an undefined value as an ARRAY reference at /usr/share/perl/
+5.10/Attribute/Handlers.pm line 185, <DATA> line 31.
END failed--call queue aborted, <DATA> line 31.

[download]

question

What's going on, what can I do alternatively?

Cheers Rolf

UPDATE: I have the same error when directly opening the source file... it seems Attribute::Handlers is buggy...

In reply to Reading sourcecode at parsing/compilation (CHECK) time? by LanX

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