Perhaps we can start from here: https://docs.google.com/spreadsheets/d/1j6_YSCc_8gEReAWFP84geI30wlnsz7uMFq4TCm7GRz8/edit?usp=sharing
Best, Taewoo On Mon, Sep 28, 2015 at 6:05 PM, Mike Carey <[email protected]> wrote: > At times like this it's useful to take a quick look at what other systems > do, if they have such functions - e.g., are there precedents we should base > our answer on? (In Java, Postgres, MySQL, ...) > > > On 9/28/15 6:03 PM, Jianfeng Jia wrote: > >> Hi Devs, >> >> Another question about the string functions. >> >> The example code on the >> http://asterixdb.ics.uci.edu/documentation/aql/functions.html#StringFunctions >> < >> http://asterixdb.ics.uci.edu/documentation/aql/functions.html#StringFunctions> >> shows that these two function are suppose to be called after contains(). I >> wonder what is the expected behavior if the they can't find the match >> pattern? >> >> The current result is confusing. >> >> e.g. >> let $x := "substring" >> return [ substring-before($x, "subx"), substring-after($x, “subx”)] >> >> it will return >> [ [ "subst", "" ] >> ] >> Should we always return an empty string in such case, or throw an >> exception like “you shall filter the result by contain() first” ? >> IMHO, I’d like to return a null string. Any opinion? >> >> >> Best, >> >> Jianfeng Jia >> PhD Candidate of Computer Science >> University of California, Irvine >> >> >> >
