in reply to Re^5: language selection via libxml
in thread language selection via libxml

I am trying to get this as I believe Xpath expressions to be very powerful and I've always had a hard time understanding them.

The two examples marked OK above seem to behave the same way: 

use XML::LibXML;
my $tree = XML::LibXML->load_xml(string => <<'EOT');
<?xml version="1.0"?>
<language>
    <english>
        <widget ID="1">input</widget>
        <widget ID="2">output</widget>
    </english>
    <deutsch>
        <widget ID="1">eingabe</widget>
        <widget ID="2">ausgabe</widget>
    </deutsch>
</language>
EOT

test('english',1);
test('deutsch',1);

sub test {
    my ($language,$id) = @_;
    my @result=$tree->findnodes("/language/$language/widget[\@ID=$id]"
+);
    print $_->textContent . "\n" for @result;
    my @result2=$tree->findnodes("/language/$language/widget[\@ID='$id
+']");
    print $_->textContent . "\n" for @result2;
}

[download]
Output: 
input
input
eingabe
eingabe

[download]

Replies are listed 'Best First'.
Re^7: language selection via libxml
by choroba (Cardinal) on Jan 20, 2014 at 13:46 UTC
    OK, numbers do not have to be enclosed in quotes, and a valid identifier cannot start with a digit. Try using "a" and "b" as the identifiers, though.
    لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
[reply]
      I see. So when I changed the ID values to 'a' and 'b' the only one that worked was the one with single quotes: 
      "/language/$language/widget[\@ID='$id']"

      [download]
      I'm not quite sure what you mean by "a valid identifier cannot start with a digit" - what does 'identifier' refer to?
[reply]
[d/l]
        The reason why 1 cannot be mistaken for an element name is that element names cannot start with digits. Use "a" and "b" with the following XML to see what is matched against what: 
        #!/usr/bin/perl
use warnings;
use strict;

use XML::LibXML;
my $tree = 'XML::LibXML'->load_xml(string => <<'EOT');
<?xml version="1.0"?>
<language>
    <english>
        <widget ID="a">input</widget>
        <widget ID="b">output</widget>
    </english>
    <deutsch>
        <widget ID="b">
          eingabe
          <b>b</b>
        </widget>
        <widget ID="b">ausgabe</widget>
    </deutsch>
</language>
EOT

test('english', 'a');
test('deutsch', 'b');

sub test {
    my ($language,$id) = @_;
    my @result = $tree->findnodes("/language/$language/widget[\@ID=$id
+]");
    print $_->textContent . "\n" for @result;
    my @result2 = $tree->findnodes("/language/$language/widget[\@ID='$
+id']");
    print $_->textContent . "\n" for @result2;
}

        [download]
        لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
[reply]
[d/l]

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