W3C home > Mailing lists > Public > public-rdf-wg@w3.org > July 2013

Re: ACTION-278: grammar for TriG

From: Eric Prud'hommeaux <eric@w3.org>
Date: Mon, 8 Jul 2013 00:27:47 -0400
To: Gregg Kellogg <gregg@greggkellogg.net>
Cc: Andy Seaborne <andy@apache.org>, RDF WG <public-rdf-wg@w3.org>
Message-ID: <20130708042745.GA13572@w3.org>
* Gregg Kellogg <gregg@greggkellogg.net> [2013-07-07 15:22-0600]
> 
> Gregg Kellogg
> gregg@greggkellogg.net
> 
> On Jul 6, 2013, at 4:49 PM, Eric Prud'hommeaux <eric@w3.org> wrote:
> 
> > https://www.w3.org/2011/rdf-wg/track/actions/278 says
> > [[
> > Create new grammar for TriG that includes optional graph keywords and
> > make {} optional around the default graph
> > ]]
> > 
> > I followed Sandro's lead and replaced
> > [[
> >  [1] 	turtleDoc 	::= 	statement*
> >  [2] 	statement 	::= 	directive | triples '.'
> > ]]
> > with:
> > [[
> >  trigDoc           ::= statement*
> >  statement         ::= directive | tripleOrBareGraph | graphword | wrappedDefault
> >  tripleOrBareGraph ::= (iri | BlankNode | collection | BlankNodePropertyList) ('{' TriplesTemplate '}' | PropertyListNotEmpty '.')
> >  graphword         ::= "GRAPH" (iri | BlankNode) '{' TriplesTemplate '}'
> >  wrappedDefault    ::= '{' TriplesTemplate '}'
> > ]].
> > This permits docs like:
> > [[
> >  PREFIX p: <ns>
> >  @prefix p: <ns> .
> >  <s> <p> <o> .
> >  { <s> <p> <o> }
> >  <g> { <s> <p> <o> }
> >  GRAPH <g> { <s> <p> <o> }
> >  _:g { <s> <p> <o> }
> >  GRAPH _:g { <s> <p> <o> }
> > ]].
> > 
> > 
> > We can be conservative or liberal about what can go the the graph name
> > position:
> > [[
> > tripleOrBareGraph ::= (iri | BlankNode) ('{' TriplesTemplate '}' | PropertyListNotEmpty '.')
> >                    | collection PropertyListNotEmpty '.'
> >                    | BlankNodePropertyList PropertyListNotEmpty? '.'
> > [[
> > or more liberal:
> > [[
> > tripleOrBareGraph ::= (iri | BlankNode | collection | BlankNodePropertyList) ('{' TriplesTemplate '}' | PropertyListNotEmpty '.')
> > ]]
> > which permits bnodes from collections and property lists like:
> > [[
> >  (1 2 3) { <s> <p> <o> }
> >  [ <p> <o> ] { <s> <p> <o> }
> > ]].
> > I prefer the latter as it encourages the good practice of making
> > assertions about labeled graphs, e.g.
> > [[
> >  [ :utteredBy "Bob" ] { <moon> <madeOf> <greenCheese> }
> > ]]
> 
> A problem with this grammar is that it doesn't allow Andy's test trig-turtle-05.trig [1]:
> 
> [[
> # Turtle is TriG
>  prefix : <http://example/> 
> 
>  [ :p :o ] .
> ]]
> 
> This is because the BlankNodePropertyList matches the first element of tripleOrBarGraph, and it expects to see a PropertyListNotEmpty '.'
> 
> SPARQL doesn't suffer from this problem, as a graph name can't be a collection of BlankNodePropertyList.
> 
> I find the following version of tripleOrBareGraph works:
> 
> [[
> [3g]   tripleOrBareGraph     ::= (iri | BlankNode) (wrappedDefault | PropertyListNotEmpty '.')
>                                | (collection | BlankNodePropertyList) (wrappedDefault | PropertyListNotEmpty? '.')
> 
> ]]

agreed. I pass all of Andy's tests with this grammar.


> Gregg
> 
> [1] https://dvcs.w3.org/hg/rdf/file/1f470c4ebbc0/trig/tests2/trig-turtle-05.trig
> 
> 
> > Following is <http://www.w3.org/2005/01/yacker/uploads/trigS_new>:
> > 
> > trigDoc           ::= statement*
> > statement         ::= directive | tripleOrBareGraph | graphword | wrappedDefault
> > #tripleOrBareGraph ::= (iri | BlankNode) ('{' TriplesTemplate '}' | PropertyListNotEmpty '.')
> > #                    | collection PropertyListNotEmpty '.'
> > #                    | BlankNodePropertyList PropertyListNotEmpty? '.'
> > tripleOrBareGraph ::= (iri | BlankNode | collection | BlankNodePropertyList) ('{' TriplesTemplate '}' | PropertyListNotEmpty '.')
> > graphword         ::= "GRAPH" (iri | BlankNode) '{' TriplesTemplate '}'
> > wrappedDefault    ::= '{' TriplesTemplate '}'
> > 
> > [3]     directive                  ::= prefixID | base | sparqlPrefix | sparqlBase
> > [4]     prefixID                   ::= PREFIX PNAME_NS IRIREF '.'
> > [5]     base                       ::= BASE IRIREF '.'
> > [5s]    sparqlBase                 ::= SPARQL_BASE IRIREF
> > [6s]    sparqlPrefix               ::= SPARQL_PREFIX PNAME_NS IRIREF
> > [52s]   TriplesTemplate            ::= TriplesSameSubject ( '.' TriplesTemplate? )?
> > [6]     TriplesSameSubject         ::= subject PropertyListNotEmpty | BlankNodePropertyList PropertyList
> > [76s]   PropertyList               ::= PropertyListNotEmpty?
> > [77s]   PropertyListNotEmpty       ::= Verb ObjectList (';' (Verb ObjectList)?)*
> > [8]     ObjectList                 ::= object (',' object)*
> > [9]     Verb                       ::= predicate | 'a'
> > [10]    subject                    ::= iri | BlankNode | collection
> > [11]    predicate                  ::= iri
> > [12]    object                     ::= iri | BlankNode | collection | BlankNodePropertyList | literal
> > [13]    literal                    ::= RDFLiteral | NumericLiteral | BooleanLiteral
> > [14]    BlankNodePropertyList      ::= '[' PropertyListNotEmpty ']'
> > [15]    collection                 ::= '(' object* ')'
> > [16]    NumericLiteral             ::= INTEGER | DECIMAL | DOUBLE
> > [128s]  RDFLiteral                 ::= String (LANGTAG | '^^' iri)?
> > [133s]  BooleanLiteral             ::= 'true' | 'false'
> > [17]    String                     ::= STRING_LITERAL1 | STRING_LITERAL2 | STRING_LITERAL_LONG1 | STRING_LITERAL_LONG2
> > [135s]  iri                        ::= IRIREF | PrefixedName
> > [136s]  PrefixedName               ::= PNAME_LN | PNAME_NS
> > [137s]  BlankNode                  ::= BLANK_NODE_LABEL | ANON
> > 
> > @terminals
> > 
> > [18]    IRIREF                     ::= '<' ([^#x00-#x20<>\"{}|^`\\] | UCHAR)* '>'
> > [139s]  PNAME_NS                   ::= PN_PREFIX? ':'
> > [140s]  PNAME_LN                   ::= PNAME_NS PN_LOCAL
> > [141s]  BLANK_NODE_LABEL           ::= '_:' (PN_CHARS_U | [0-9]) ((PN_CHARS | '.')* PN_CHARS)?
> > [0]     GRAPH1                      ::= [Gg][Rr][Aa][Pp][Hh]
> > [0]     SPARQL_PREFIX              ::= [Pp][Rr][Ee][Ff][Ii][Xx]
> > [0]     SPARQL_BASE                ::= [Bb][Aa][Ss][Ee]
> > [0]     BASE                       ::= '@base'
> > [0]     PREFIX                     ::= '@prefix'
> > [144s]  LANGTAG                    ::= BASE | PREFIX | '@' [a-zA-Z]+ ('-' [a-zA-Z0-9]+)*
> > [19]    INTEGER                    ::= [+-]? [0-9]+
> > [20]    DECIMAL                    ::= [+-]? [0-9]* '.' [0-9]+
> > [21]    DOUBLE                     ::= [+-]? ([0-9]+ '.' [0-9]* EXPONENT | '.' [0-9]+ EXPONENT | [0-9]+ EXPONENT)
> > [154s]  EXPONENT                   ::= [eE] [+-]? [0-9]+
> > [155s]  STRING_LITERAL1            ::= "'" ([^#x27#x5C#xA#xD] | ECHAR | UCHAR)* "'"
> > [156s]  STRING_LITERAL2            ::= '"' ([^#x22#x5C#xA#xD] | ECHAR | UCHAR)* '"'
> > [157s]  STRING_LITERAL_LONG1       ::= "'''" (("'" | "''")? [^'\\] | ECHAR | UCHAR)* "'''"
> > [158s]  STRING_LITERAL_LONG2       ::= '"""' (('"' | '""')? [^"\\] | ECHAR | UCHAR)* '"""'
> > [26]    UCHAR                      ::= '\\u' HEX HEX HEX HEX | '\\U' HEX HEX HEX HEX HEX HEX HEX HEX
> > [159s]  ECHAR                      ::= '\\' [tbnrf\\"']
> > [161s]  WS                         ::= #x20 | #x9 | #xD | #xA
> > [162s]  ANON                       ::= '[' WS* ']'
> > [163s]  PN_CHARS_BASE              ::= [A-Z] | [a-z] | [#x00C0-#x00D6] | [#x00D8-#x00F6] | [#x00F8-#x02FF] | [#x0370-#x037D] | [#x037F-#x1FFF] | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF] | [#x3001-#xD7FF] | [#xF900-#xFDCF] | [#xFDF0-#xFFFD] | [#x10000-#xEFFFF]
> > [164s]  PN_CHARS_U                 ::= PN_CHARS_BASE | '_'
> > [166s]  PN_CHARS                   ::= PN_CHARS_U | '-' | [0-9] | #x00B7 | [#x0300-#x036F] | [#x203F-#x2040]
> > [167s]  PN_PREFIX                  ::= PN_CHARS_BASE ((PN_CHARS | '.')* PN_CHARS)?
> > [168s]  PN_LOCAL                   ::= (PN_CHARS_U | ':' | [0-9] | PLX) ((PN_CHARS | '.' | ':' | PLX)* (PN_CHARS | ':' | PLX))?
> > [169s]  PLX                        ::= PERCENT | PN_LOCAL_ESC
> > [170s]  PERCENT                    ::= '%' HEX HEX
> > [171s]  HEX                        ::= [0-9] | [A-F] | [a-f]
> > [172s]  PN_LOCAL_ESC               ::= '\\' ('_' | '~' | '.' | '-' | '!' | '$' | '&' | "'" | '(' | ')' | '*' | '+' | ',' | ';' | '=' | '/' | '?' | '#' | '@' | '%')
> > 
> > @pass: [ \t\r\n]+ | '#' [^\r\n]*
> > 
> > 
> > -- 
> > -ericP
> > 
> 

-- 
-ericP
Received on Monday, 8 July 2013 04:28:17 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 17:04:30 UTC