alcamo/rdf-literal

RDF literals

0.1.13 2026-07-07 15:13 UTC

Requires

• php: 7.3 - 8.5
• alcamo/binary-data: ^0.6
• alcamo/collection: ^0.2
• alcamo/time: ^0.2
• alcamo/uri: ^0.2
• alcamo/xml: ^0.1

Requires (Dev)

• php-ds/php-ds: ^1.3
• phpunit/phpunit: ^9.5
• squizlabs/php_codesniffer: 3.*

Apache-2.0

• RDF
• datatype
• literal

Published on Packagist.org on 2026-07-07 15:14 UTC

README

use alcamo\rdf_literal\LiteralFactory;

include $_composer_autoload_path ?? __DIR__ . '/../vendor/autoload.php';

$factory = new LiteralFactory();

$number = $factory->create(1970);

echo $number . PHP_EOL;

echo $number->getDatatypeUri() . PHP_EOL;

$year = $factory->create(1970, LiteralFactory::XSD_NS . 'gYear');

echo $year . PHP_EOL;

echo $year->getDatatypeUri() . PHP_EOL;

echo "Literals are "
    . ($year->equals($number) ? '' : 'not')
    . ' equal' . PHP_EOL;

This example is contained in this package as a file in the bin directory. It will output

1970
http://www.w3.org/2001/XMLSchema#integer
1970
http://www.w3.org/2001/XMLSchema#gYear
Literals are not equal

Overview

The classes that implement LiteralInterface represent the concept of RDF Literals, i.e. data elements that have a datataype and may have a language tag.

Among others, this allows to:

• Create values of various types from strings, governed by an XSD datatype URI.
• Add a __toString() function to values which are not stringable by nature.
• Add a custom __toString() function which differs from the default representation of a value.
• Distinguish values that may be represented the same way in PHP but have different meanings.

See the doxygen documentation for details.

The literal classes in this package do not check whether the given datatype is actually supported by the class, i.e. derived from the class's default datatype. This is a deliberate design decision, on the one hand to obtain lightweight literal classes, on the other hand to avoid a bidirectional dependency between this package and alcamo/dom.

The alcamo/rdf-literal-workbench package is provided to create and validate literal objects based on knowledge of an XML Schema.