Andy, what if I'm sending the query to a remote endpoint that does not support Java style regex syntax? Do I need to use FmtUtils then?
Looking at the example from SPARQL 1.1 STR() [1]: This query selects the set of people who use their work.example address in their foaf profile: PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT ?name ?mbox WHERE { ?x foaf:name ?name ; foaf:mbox ?mbox . FILTER regex(str(?mbox), "@work\\.example$") } How does "work.example" become "work\\.example"? Is one backslash escaping the regex, and the second one escaping the literal? How do I achieve this with Jena? [1] http://www.w3.org/TR/2013/REC-sparql11-query-20130321/#func-str Martynas On Tue, Jan 21, 2014 at 10:10 AM, Andy Seaborne <a...@apache.org> wrote: > Works for me: > > SELECT * { > VALUES ?o { "+35" "abc+35def" } > FILTER regex(?o , "\\Q+35\\E", "i") > } > > and in Java you need \\\\ due to both the levels of escaping (Java text, > SPARQL). > > [[ > Regex: Pattern exception: java.util.regex.PatternSyntaxException: Dangling > meta character '+' near index 0 > ]] > which gives the game away it's using java regexs :-) > > The regex engine is Java's and the string is used untouched. > > Strictly, it should be XSD v1 which are slightly different: > > http://www.w3.org/TR/xmlschema-2/#regexs > > and there is a strict Xerces provided alternative if you want exact XSD > regular expressions. > > XSD and Java differs in only very small ways (e.g. XSD has one extra > modifier flag, "m", XSD has no \Q\E, and XSD has "Is" for unicode code > blocks inside \p e.g. \p{IsMongolian}) > > And now > http://www.w3.org/TR/xmlschema11-2/#regexs > > Andy > > > On 21/01/14 02:32, Joshua TAYLOR wrote: >> >> My apologies. I replied too quickly. I just wrote this test with >> Jena's command line tools. To match the string "+35", I had to use the >> "\\+35" in the query: >> >> select ?label where { >> values ?label { "+35" "-35" } >> filter(regex(str(?label),"\\+35")) >> } >> >> --------- >> | label | >> ========= >> | "+35" | >> --------- >> >> That's _two_ slashes in the query string, which means that in Java >> you'd end up writing >> >> String query = ... + "filter(regex(...,\"\\\\+35\")" + ...; >> >> Sorry for the hasty and inaccurate reply. >> >> On Mon, Jan 20, 2014 at 9:27 PM, Joshua TAYLOR <joshuaaa...@gmail.com> >> wrote: >>> >>> On Mon, Jan 20, 2014 at 8:48 PM, Martynas Jusevičius >>> <marty...@graphity.org> wrote: >>>> >>>> OK maybe "+35" was a bad example. But isn't "+" a special char in >>>> SPARQL regex? And there are more like "*", "?" etc. >>>> http://www.w3.org/TR/xpath-functions/#regex-syntax >>> >>> >>> >>> Oh, good point. But if it needs to be escape with a slash, then wouldn't >>> >>> filter regex(str(?label), "\+35") >>> >>> be fine? Note that if you're constructing this programmatically, you >>> might end up writing code like >>> >>> String queryString = ... + "filter regex(str(?label), \"\\+35\")" + >>> ...; >>> >>> -- >>> Joshua Taylor, http://www.cs.rpi.edu/~tayloj/ >> >> >> >> >
