Appendix: IANA Considerations

This section is a copy of the media type registration, submitted to the Internet Engineering Steering Group (IESG)1 and approved by IANA2 on July 20, 2022..

application/vnd.datalog

Media type name:
application
<dt>Media subtype name:</dt>
<dd><code>vnd.datalog</code></dd>

<dt>Required parameters:</dt>
<dd>N/A</dd>

<dt>Optional parameters:</dt>
<dd>

The optional “features” parameter allows the transport to identify language features used within the representation. The value of this parameter is a comma-separated list of feature identifiers supported by the specification. Feature identifiers conform to the following EBNF production.

id ::= LC_ALPHA ( ALPHA | DIGIT | UNDERSCORE )* ;

The purpose of this parameter is to save a client from having to parse a document if the features identified in the parameter are unsupported by them. If this parameter is specified more than once its values MUST be aggregated into a set, removing duplicates.

The optional “dialect” parameter identifies the tool which generated the document, there are some existing tools with extensive usage that deviate from this core specification. Dialect identifiers conform to the same id production described for feature identifiers.

If this parameter is specified more than once, the first value MUST be used and any subsequent value MUST be discarded. 

<dt>Encoding considerations:</dt>
<dd>The content encoding of a Datalog text document is always UTF-8.</dd>

<dt>Security considerations:</dt>
<dd>

This media type does include program code for a Datalog interpreter to execute. However, as Datalog is a restricted deductive logic language its execution environment is limited to entailment and query, and not capable of general purpose programming.

The Datalog language does contain references to additional resources that may be required to complete a program. For example, an “input” processing instruction will add facts from an external resource (using IRIs) to an extensional relation whereas the “output” processing instruction will be some local resource that may be written to. The ability to include malicious data in an input file is limited by the supported representations such as CSV. The ability to write to a local system may be intercepted by a parser to redirect to safe locations, and as such the allowed reference is always relative.

Privacy and integrity services are not required, or provided, by this specification. 

<dt>Interoperability considerations:</dt>
<dd>

A number of vendors have extended Datalog with additional syntax, this has been a general problem for some years. The introduction of a common standard, and support for the “dialect” parameter will help clients understand the potential parsing issues of a specific document. 

<dt>Published specification:</dt>
<dd>
[https://datalog-specs.info/vnd_datalog_text/abstract.html](https://datalog-specs.info/vnd_datalog_text/abstract.html); Version: 1.0, 2 April 2022.
</dd>

<dt>Applications which use this media:</dt>
<dd>Applications that need to upload, download, or transfer Datalog
programs.</dd>

<dt>Fragment identifier considerations:</dt>
<dd>None identified by this specification.</dd>

<dt>Additional information:</dt>
<dd>
    <dl>
        <dt>Deprecated alias names for this type:</dt>
        <dd>N/A</dd>
        <dt>Magic number(s):</dt>
        <dd>N/A</dd>
        <dt>File extension(s):</dt>
        <dd>dl</dd>
        <dt>Macintosh file type code:</dt>
        <dd>TEXT</dd>
        <dt>Object Identifiers:</dt>
        <dd>N/A</dd>
    </dl>
</dd>

<dt>Person & email address to contact for further information:</dt>
<dd>Simon Johnston, < href="mailto:johnstonskj@gmail.com">johnstonskj@gmail.com</a></dd>

<dt>Intended usage:</dt>
<dd>COMMON</dd>

<dt>Restrictions on usage:</dt>
<dd>None identified by this specification.</dd>

<dt>Author:</dt>
<dd>Simon Johnston, < href="mailto:johnstonskj@gmail.com">johnstonskj@gmail.com</a></dd>

<dt>Change controller:</dt>
<dd>N/A</dd>