Abstract:

Pentals is a language designed to be easily read and written by both humans and automated agents. It is an an extension of  N-Triples. This means that every well formed N-Triple is also a well formed Pental.  Pentals extends N-triples by adding the optional attributes: context, sequence, and the dialogue performatives: ". ? !".   Names are allowed in the place of uriref; and they may be prefixed with namespaces. Compound names are supported.  

Authors:

Seth Russell  <mailto:seth@robustai.net>
Sean B. Palmer <mailto:sean@mysterylights.com>

EBNF definition of Pentals grammar:

1	pentalsDoc	::=	line*
2	line	::=	ws* (comment | pental) ? eoln
3	comment	::=	'#' (character - ( cr | lf ) )*
4	pental	::=	subject ws+ predicateSlot ws+ object ws+ ((context | ',') seq?)? terminal? ws*
5	context	::=	name | nodeID |  compoundName
6	subject	::=	name | nodeID |  compoundName
7	predicateSlot	::=	name | compoundName
8	object	::=	name | compoundName | literal
9	seq	::=	realNumber
10	terminal	::=	'.' | '?' | '!'
11	uriref	::=	'<' absoluteURIref '>'
12	compoundName	::=	'(' ws* name (ws+ name)+ ws* ')'
13	name	::=	uriref | nameToken | namespacePrefix ':' nameToken
14	namespacePrefix	::=	namespacePrefix ::= [A-Za-z][A-Za-z0-9_]*
15	nodeID	::=	'_:' nameToken
16	literal	::=	langstring | xmlString
17	langString	::=	'"' string '"' ('-' language)?
18	xmlString	::=	'xml' langString
19	language	::=	( character - ( '.' | ws ) )+ and containing any allowed xml:lang content as defined in http://www.w3.org/TR/REC-xml#sec-lang-tag
20	ws	::=	space | tab
21	eoln	::=	cr | lf | cr lf
22	space	::=	#x20 /* US-ASCII space - decimal 32 */
23	cr	::=	#xD /* US-ASCII carriage return - decimal 13 */
24	lf	::=	#xA /* US-ASCII linefeed - decimal 10 */
25	tab	::=	#x9 /* US-ASCII horizontal tab - decimal 9 */
26	string	::=	character* with escapes. Defined in section Strings
27	nameToken	::=	[A-Za-z0-9_]+
28	realNumber	::=	[0-9]+  ('.' [0-9]+)?
29	absoluteURIref	::=	defined in section URI References  also see #rdfig discussion
30	character	::=	[#x20-#x7E] /* US-ASCII space to decimal 127 */

Implementations:

A parser for this grammar has been implemented as the python function parsePentals(string) in the module seagent.py.

Examples:

1	SethBot ownedBy Seth.	......mentograph here.....................................
2	<http://

References:

    N-Triples <http://www.w3.org/TR/rdf-testcases/#ntrip_grammar>

    EBNF <http://www.w3.org/TR/REC-xml#sec-notation>

    SEAGENT <http://robustai.net/mentography/seagent.py>