XML::Compile to generate sample XML from schema with enumeration and choice

Question

Following some existing tutorials, I created below perl script to generate XML from xsd.

Script:

#!/opt/perl/bin/perl -w
use warnings;
use strict;
use XML::Compile::Schema;
use XML::LibXML::Reader;
use XML::Compile::Util qw/pack_type/;

my $in_qfn  = $ARGV[0];
my $out_qfn = $ARGV[1];

open (OUT, ">$out_qfn") || die "Unable to create output file: $out_qfn
";

# Generate the hash of xml
my $schema = XML::Compile::Schema->new($in_qfn);
my $type = pack_type 'urn:testsample','Document';
my $data = $schema->template('PERL', $type);
$data =~ s/#.*//g;
$data =~ s/\s*//g;
$data = eval($data);

# Print the xml
my $doc = XML::LibXML::Document->new('1.0','UTF-8');
my $write = $schema->compile(WRITER=>$type);
my $xml = $write->($doc,$data);
$doc->setDocumentElement($xml);
print OUT $doc->toString(1);

Input Schema:

The output is correct. To take it further, in the example schema, there are choice elements, enumerations and repetitive elements. I would like to:

1. iterate all the possible values
2. generate maximum repetitive elements, if unbounded then 99
3. generate all choice values
4. split them into multiple XML files such that every XML is valid against the original schema.

The output XML files amount is: i*j (i: the amount of choices in each node recursively, can be i1*i2*i3... j: the amount of enumerations in each node recursively, can be j1*j2*j3...)

In this case, it outputs 2*3=6 XML files (if there is an embedded node with 2 enumeration values, then it becomes 2*2*3=12 XML files), similar to:

XML file 1:



    AA
    example
    example
    example
    
        example

XML File 2:



    BB
    example
    example
    example
    
        example

XML File 3:



    AA
    example
    example
    example
    
        2017-10-2

XML File 4:



    BB
    example
    example
    example
    
        2017-10-2

XML File 5:



    AA
    example
    example
    example
    
        example
        example

XML File 6:



    BB
    example
    example
    example
    
        example
        example

I firstly stuck to get the correct value for i and j, as they will be variables used in the generated XML file names, then the possible split. Any help is appreciated!

user_8753501 · Answer

(I am the author of XML::Compile) This can never lead to an generic solution, so it is probably not worth the effort...

Nearly all elements have different values which you need to test, enumeration seems to be special, but isn't. For instance, an integer is an enumeration as well. Would you walk all its values? The number of combinations explode.

When you want to collect more info from the schema than the template() function shows, try to extend XML::Compile::Translate::Template. It offers you details from the xsd in simple HASH structures.

Success

user_589924 · Answer

You don't seem to have a grasp of the size of the numbers involved.

Let me add some limits:

We limit bounded repetitions to four test cases of min, min+1, max-1 and max repetitions.
We limit unbounded repetitions to three test cases of min, min+1 and min+100 repetitions.
We always use the same value for xs:string and xs:date.

Even with those limits, your trivially simple schema would result in 4 × 10¹⁷⁹ combinations (or 4 × 10¹⁹ combinations if we reduce the third case of unbounded repetitions from min+100 to min+10).

To get an idea of the scale of these numbers, consider this: There are only 10⁸⁰ atoms in the observable universe.

A generic solution is just not possible.

The number was obtained using the following program:

use strict;
use warnings qw( all );
use feature qw( say );

sub sum { my $acc = 0; $acc += $_ for @_; $acc }
sub mul { my $acc = 1; $acc *= $_ for @_; $acc }

sub choice { sum @_ }
sub sequence { mul @_ }

sub repeat {
   my ($x, $min, $max) = @_;
   my @exps;
   if (defined($max)) {
      @exps = ( $min, $min+1, $max-1, $max );
      my $diff = $max - $min;
      die if $diff < 0;
      splice @exps, $diff+1 if $diff < 3;
   } else {
      @exps = ( $min, $min+1, $min+100 );   
   }

   return choice map { $x ** $_ } @exps;
}

# optional($x) is a shortcut for repeat($x, 0, 1)
sub optional { 1 + $_[0] }

sub Document { repeat(address(), 1) }
sub address { sequence optional(Pname()), repeat(street(), 0, 3), contacttype() }
sub contacttype { optional(contacttype_choice()) }
sub contacttype_choice { choice bday(), email(), repeat(postal(), 1, 2) }
sub Pname { 2 }
sub street { 1 }
sub bday { 1 }
sub email { 1 }
sub postal { 1 }

say Document();

The above program uses the following simpler-but-equivalent definition of contacttype:

XML::Compile to generate sample XML from schema with enumeration and choice

2 Answers