25 Apr 2005 chromatic   » (Master)


Why call walkoptree() yourself (see B.pm) when you have the power of XPath (at least as much as Class::XPath supports?


use strict; use warnings;

use B::XPath;

use vars qw( $foo $bar );

sub some_sub { my $x = shift; $foo = $x; print "\$x is $x\n\$foo is $foo\n"; }

my $node = B::XPath->fetch_root( \&some_sub );

for my $bar ($node->match( '//gvsv[@NAME="foo"]' )) { printf( "Found global '%s' at %s:%d\n (defined at %s:%d)\n", map { $bar->$_ } qw( NAME find_file find_line FILE LINE ) ); }

I'm sure you're on the edge of your seat for the output:

$ perl find_global_name.pl
Found global 'foo' at find_global_name.pl:13
  (defined at /usr/lib/perl5/5.8.6/vars.pm:35)
Found global 'foo' at find_global_name.pl:14
  (defined at /usr/lib/perl5/5.8.6/vars.pm:35

There are two drawbacks (besides the fact that it's a proof of concept and not releasable yet): Class::XPath has little axis support and you have to know an awful lot about the structure of the optree for which you want to search. I think the latter is solvable, but it will require more thought.

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