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diff --git a/eg/hrefsub b/eg/hrefsub
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+#!/usr/bin/perl
+
+# Perform transformations on link attributes in an HTML document.
+# Examples:
+#
+#  $ hrefsub 's/foo/bar/g' index.html
+#  $ hrefsub '$_=URI->new_abs($_, "http://foo")' index.html
+#
+# The first argument is a perl expression that might modify $_.
+# It is called for each link in the document with $_ set to
+# the original value of the link URI.  The variables $tag and
+# $attr can be used to access the tagname and attributename
+# within the tag where the current link is found.
+#
+# The second argument is the name of a file to process.
+
+use strict;
+use HTML::Parser ();
+use URI;
+
+# Construct a hash of tag names that may have links.
+my %link_attr;
+{
+    # To simplify things, reformat the %HTML::Tagset::linkElements
+    # hash so that it is always a hash of hashes.
+    require HTML::Tagset;
+    while (my($k,$v) = each %HTML::Tagset::linkElements) {
+	if (ref($v)) {
+	    $v = { map {$_ => 1} @$v };
+	}
+	else {
+	    $v = { $v => 1};
+	}
+	$link_attr{$k} = $v;
+    }
+    # Uncomment this to see what HTML::Tagset::linkElements thinks are
+    # the tags with link attributes
+    #use Data::Dump; Data::Dump::dump(\%link_attr); exit;
+}
+
+# Create a subroutine named 'edit' to perform the operation
+# passed in from the command line.  The code should modify $_
+# to change things.
+my $code = shift;
+my $code = 'sub edit { local $_ = shift; my($attr, $tag) = @_; no strict; ' .
+           $code .
+           '; $_; }';
+#print $code;
+eval $code;
+die $@ if $@;
+
+# Set up the parser.
+my $p = HTML::Parser->new(api_version => 3);
+
+# The default is to print everything as is.
+$p->handler(default => sub { print @_ }, "text");
+
+# All links are found in start tags.  This handler will evaluate
+# &edit for each link attribute found.
+$p->handler(start => sub {
+		my($tagname, $pos, $text) = @_;
+		if (my $link_attr = $link_attr{$tagname}) {
+		    while (4 <= @$pos) {
+			# use attribute sets from right to left
+			# to avoid invalidating the offsets
+			# when replacing the values
+			my($k_offset, $k_len, $v_offset, $v_len) =
+			    splice(@$pos, -4);
+			my $attrname = lc(substr($text, $k_offset, $k_len));
+			next unless $link_attr->{$attrname};
+			next unless $v_offset; # 0 v_offset means no value
+			my $v = substr($text, $v_offset, $v_len);
+			$v =~ s/^([\'\"])(.*)\1$/$2/;
+			my $new_v = edit($v, $attrname, $tagname);
+			next if $new_v eq $v;
+			$new_v =~ s/\"/&quot;/g;  # since we quote with ""
+			substr($text, $v_offset, $v_len) = qq("$new_v");
+		    }
+		}
+		print $text;
+	    },
+	    "tagname, tokenpos, text");
+
+# Parse the file passed in from the command line
+my $file = shift || usage();
+$p->parse_file($file) || die "Can't open file $file: $!\n";
+
+sub usage
+{
+    my $progname = $0;
+    $progname =~ s,^.*/,,;
+    die "Usage: $progname <perlexpr> <filename>\n";
+}