(registered 2022-07-20, last updated 2022-07-20)

Media type name: application

Media subtype name: vnd.datalog

Required parameters: N/A

Optional parameters:

   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 pragma 
   identifiers supported by the specification. Feature pragmas exist 
   to turn on/off certain language capabilities, and 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.

   Feature identifiers conform to the following EBNF production.

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

   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.

Encoding considerations: 8bit

   The content encoding of a Datalog text document MUST be UTF-8

Security considerations: 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.

Interoperability considerations: 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.

Published specification:

   https://datalog-specs.info/vnd_datalog_text/abstract.html;
   Version: 1.0, 2 April 2022.

Applications which use this media: Applications that need to upload, 
   download, or transfer Datalog programs.

Fragment identifier considerations: None identified by this 
   specification.

Additional information:

   1. Deprecated alias names for this type: N/A
   2. Magic number(s): N/A
   3. File extension(s): dl
   4. Macintosh file type code: TEXT
   5. Object Identifiers: N/A

Person & email address to contact for further information:

   Simon Johnston, johnstonskj&gmail.com

Intended usage: COMMON

Restrictions on usage: None identified by this specification.

Author: Simon Johnston, johnstonskj&gmail.com

Change controller: N/A