string(5) string(0.5) string(-0.5) string(true()) string(false()) concat("titi","toto") concat("titi","toto","tata") concat("titi",'toto') concat("titi",'toto',"tata","last") starts-with("tititoto","titi") starts-with("tititoto","to") contains("tititototata","titi") contains("tititototata","toto") contains("tititototata","tata") contains("tititototata","tita") substring("12345",2,3) substring("12345",2) substring("12345",-4) substring("12345",3.4) substring("12345",3.6) substring("12345",1.5,2.6) substring("12345",2.2,2.2) substring("12345",0,3) substring("12345",-8,10) substring("12345",4,-10) substring("12345",0 div 0, 3) substring("12345",1, 0 div 0) substring("12345",1 div 0, 3) substring("12345",3,-1 div 0) substring("12345",-42, 1 div 0) substring("12345",-1 div 0, 1 div 0) substring("12345",-1 div 0,5) string-length("") string-length("titi")