parseUpdate refuses valid queries

[eggplants]

SPARQLWrapper's way to judge given query's type is to match clauses with regex patterns. So I'm trying to use from rdflib.plugins.sparql.parser import parseQuery, parseUpdate for judging.

But I found few queries in test_wrapper.py was refused by parseUpdate.

• parseUpdate("WITH <urn:graph> DELETE DATA { <urn:john> <urn:likes> <urn:surfing> }")
  • pyparsing.exceptions.ParseException: Expected end of text, found 'WITH' (at char 0), (line:1, col:1)
• parseUpdate("PREFIX e: <http://example.org/> INSERT {e:a e:b e:c}")
  • pyparsing.exceptions.ParseException: Expected end of text, found 'INSERT' (at char 32), (line:1, col:33)

I think these queries are valid and some parser syntaxes related to parseUpdate are wrong.

ref: RDFLib/sparqlwrapper#213

[eggplants]

@gromgull @gjhiggins Please give me your expert opinion...

[ghost]

@gromgull @gjhiggins Please give me your expert opinion...

I have only very limited knowledge of SPARQL but I managed to pull these parser-satisfying usage examples out of the RDFLIb tests in the hope that they'll be useful to you:

from rdflib.plugins.sparql.parser import parseQuery
# Adding to the default graph
parseUpdate(
    "PREFIX e: <http://example.org/> INSERT DATA {e:a e:b e:c} ")
# Adding to a named graph
parseUpdate(
    "INSERT DATA {GRAPH <urn:context1> {<urn:example:tarek> <urn:example:likes> <urn:example:cheese> .}}")
# Deleting from the default graph
parseUpdate(
    "DELETE DATA {<urn:example:michel> <urn:example:likes> <urn:example:pizza>}")
# Deleting from a named graph
parseUpdate(
    "DELETE DATA {GRAPH <urn:graph> {<urn:john> <urn:likes> <urn:surfing>}}")

But you are correct in that it does appear that the usage pattern

"WITH <urn:graph> DELETE DATA { <urn:john> <urn:likes> <urn:surfing> }"

isn't supported.

[eggplants]

I'll try to debug it when I have time...

[jishnu19048]

I would like to take up this issue and submit a pr.

[gitongithub]

While working on this issue along with @jishnu19048, I found that there is partial support for with clause.
This can be seen below:

rdflib/rdflib/plugins/sparql/parser.py

Lines 1222 to 1233 in 0be6f60

	# [41] Modify ::= ( 'WITH' iri )? ( DeleteClause Optional(InsertClause) | InsertClause ) ZeroOrMore(UsingClause) 'WHERE' GroupGraphPattern
	Modify = Comp(
	"Modify",
	Optional(Keyword("WITH") + Param("withClause", iri))
	+ (
	Param("delete", DeleteClause) + Optional(Param("insert", InsertClause))
	| Param("insert", InsertClause)
	)
	+ ZeroOrMore(ParamList("using", UsingClause))
	+ Keyword("WHERE")
	+ Param("where", GroupGraphPattern),
	)

However, the expression is extended to capture DeleteClause token but not the DeleteData token because of which the usage pattern of "WITH <urn:graph> DELETE DATA { <urn:john> <urn:likes> <urn:surfing> }" goes unsupported.

We have come up with an addition to capture this and similar usage patterns and are testing them on different examples before finalizing.