use dataverse test;

let $c1 := matches("helloworld",null)
let $c2 := matches("",null)
let $c3 := matches(null,null)
let $c4 := matches("helloworld",null, "")
let $c5 := matches("",null, "i")
let $c6 := matches(null,null, null)
return {"result1": $c1, "result2": $c2, "result3": $c3, "result4": $c4, "result5": $c5, "result6": $c6}