jettero has asked for the wisdom of the Perl Monks concerning the following question:

This has come up about a jillion times before I think...

It took me a while to find this node: 31654. This one sent me off to grab XML::Checker::Parser: 31729.

XML::Checker::Parser, is probably what I want, but I've not yet gotten it to work. *sigh*

When I use the example from the man page for XML::Checker::Parser, I get this:

Can't call method "Start" on an undefined value at /usr/local/lib/perl5/site_perl/5.6.1/XML/Checker/Parser.pm line 194.

That line is:

    $_checker->Start ($tag);

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Now I figured, 

eval {
    local $XML::Checker::FAIL = \&my_fail;

    $parser->parsefile ($ARGV[0]);
};

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might be wrong... Since, the only place where I could find a $_checker.*= was in sub parse, so I tried this: 

eval {
    local $XML::Checker::FAIL = \&my_fail;

    $parser->parse;
    $parser->parsefile ($ARGV[0]);
};

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Which seemed stupid, but... no more runtime errors. The only problem is, it doesn't detect any errors in my doc either.

*sigh*, and this is just about the only XML validator for perl... So I'm at the end of my rope. Has anyone gotten XML::Checker::Parser to work? What am I don't wrong?

Replies are listed 'Best First'.
Re: XML Validator
by mirod (Canon) on Jul 31, 2001 at 07:43 UTC

    Here is an example that should show you how to use XML::Checker::Parser.

    Note that it also shows a bug in the module: characters within the doc element should trigger an error. See below for a patch for this.

    #!/bin/perl -w
use strict;

use XML::Checker::Parser;

$/=''; # records are now separated by an empty line

# first parse, a valid document
my $doc1=<DATA>;
my $p= new XML::Checker::Parser;
eval
  { local $XML::Checker::FAIL= \&my_fail;
    $p->parse( $doc1);
  };

if( $@) { print "parse 1 failed: $@\n"; }
else    { print "parse 1 OK\n";         }

# second parse, an invalid document
my $doc2=<DATA>;
$p= new XML::Checker::Parser;

eval
  { local $XML::Checker::FAIL= \&my_fail;
    $p->parse( $doc2);
  };

if( $@) { print "parse 2 failed: $@\n"; }
else    { print "parse 2 OK\n";         }

# gets an error and dies after creating the error message
sub my_fail
  {  my ($code, $msg, %context)= @_;
     die " error $code ($msg) at line $context{line}, column $context{
+column}";
  }

__DATA__
<?xml version="1.0"?>
<!DOCTYPE doc [
<!ELEMENT doc (elt+)>
<!ELEMENT elt (#PCDATA)>
]>
<!-- This document is valid -->
<doc><elt>foo</elt><elt>bar</elt></doc>

<?xml version="1.0"?>
<!DOCTYPE doc [
<!ELEMENT doc (elt|elt2)+>
<!ELEMENT elt (#PCDATA)>
<!ELEMENT elt2 EMPTY>
]>
<!-- This document is NOT valid -->
<doc>toto<!-- should trigger error but does not -->
<elt2>not empty <!-- error --></elt2><elt>foo</elt><elt>bar</elt></doc
+>

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    Now here is the patch (which I will submit to the maintainer of the module):

    228a229,232
>
>     # added by mirod
>     $checker->fail (149, "invalid text content [$str]")
>       unless $str=~ /^\s*$/;
1662c1666
< =head2 150 - 159
---
> =head2 149 - 159
1664a1669,1675
>
> =item *
>
> B<149> - invalid text content [$value]
>
> A text was found in an element that should only include sub-elements
> The text is not made of non-significant whitespace.

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Re: XML Validator
by damian1301 (Curate) on Jul 31, 2001 at 04:22 UTC
    Try removing the space between Start and ($tag); and make sure that $tag has something in it.

    I found it hard to really follow your question though. You might want to just include the whole block of code that is troublesome and you may get a better answer

    Best of luck 

    $_.=($=+(6<<1));print(chr(my$a=$_));$^H=$_+$_;$_=$^H;
print chr($_-39); # Easy but its ok.

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      *LOL* That space won't do anything, the error relates to the fact that $_checker is undefined.

      Oh, and you're not supposed to modify the perl modules... ;)

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