# Convert BNF in RDF to IETF XBNF standard used in XML for example
# See http://www.w3.org/TR/xml11/#sec-notation

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
@prefix bnf: <http://www.w3.org/2000/10/swap/grammar/bnf#>.
@prefix rul: <http://www.w3.org/2000/10/swap/grammar/bnf-rules#>.
@prefix : <http://www.w3.org/2000/10/swap/grammar/bnf2html#>.
@prefix h: <http://www.w3.org/2000/10/swap/grammar/bnf2html#>.
@prefix log: <http://www.w3.org/2000/10/swap/log#>.
@prefix string: <http://www.w3.org/2000/10/swap/string#>.
@keywords a, is, of.




#  Find all possible sequences for each term
#
{ ?x bnf:mustBeOneSequence ?y} => { ?x optionTail ?y; a Production}.

{ ?x bnf:matches [] } => { ?x a Production}.

{?x optionTail [rdf:first ?y; rdf:rest ?z]} => {
	?x 	bnf:canBeSequence ?y;
		optionTail ?z.
	?y a Sequence}.

# Label every trailing subseqeunce

{ ?seq a Sequence } => { ?seq a SequenceTail }.
{ ?seq a SequenceTail; rdf:rest ?s2 } => { ?s2 a SequenceTail }.

################

# Literal are referenced but no labels for LHS  @@ escaped

{ ?seq a SequenceTail; rdf:first ?x.
	?x log:rawType log:Literal.
	( " \"" ?x "\" " ) string:concatenation ?ref.
} => { ?x  reference ?ref }.

############	
{ 	?x a Production.
  	?x log:uri ?u.
  	(?u ".*#(.*)") string:scrape ?lab.
} =>  {
	?x bnf:label ?lab.
}.  


{ 	?x a Production; bnf:label ?lab.
  	( ?lab " ::=" ) string:concatenation ?start.
  } =>  {
	?x reference ?lab.
	(?lab 0) log:outputString ?start.
}.  

############

() seqlabel "void".

bnf:eof  reference "EOF".

# Start it, skipping use of the seqlabel of ():

{ 	?seq a SequenceTail; rdf:first ?x; rdf:rest ().
	?x reference ?lab1.
} => { ?seq seqlabel  ?lab1 }.

# This one takes forever:
{ 	?seq a SequenceTail; rdf:first ?x; rdf:rest ?tail.
	?x reference ?lab1.
	?tail seqlabel ?lab2; rdf:rest [].  # Non-null
	(?lab1 " " ?lab2) string:concatenation ?str
} => { ?seq seqlabel  ?str }.

{?x bnf:label ?lab; bnf:canBeSequence [seqlabel ?seqlab].
("\t\t|\t" ?seqlab "\n" ) string:concatenation ?para
} => {(?lab 5) log:outputString ?para}.

##########################  Regular expressions

{ 	[] a Production;
	   bnf:label ?lab;
	   bnf:matches ?regexp.
	( "\t" ?regexp "\n") string:concatenation ?regpara.
}=>{
	(?lab 6) log:outputString ?regpara.
	
}.



#end