Agreed!
On 9/28/15 9:59 PM, Chris Hillery wrote:
Beyond the signature, the documentation of the XQuery function says :
"If the value of $arg1 does not contain a string that is equal to the value
of $arg2, then the function returns the zero-length string."
So I'd say your inference is correct.
The XQuery doc also explains what happens if $arg1 or $arg2 is empty, and
we should probably emulate that as well.
Ceej
aka Chris Hillery
On Sep 28, 2015 9:29 PM, "Jianfeng Jia" <[email protected]> wrote:
Thanks for the great summary provided by Taewoo!
The XQuery’s signature shows that it always returns a string:
fn:substring-before($arg1 as xs:string?, $arg2 as xs:string?) as xs:string
And the Marklogic's returns an option[string].
fn.substringBefore(
$input <https://docs.marklogic.com/fn.substringBefore#input> as
String?,
$before <https://docs.marklogic.com/fn.substringBefore#before> as
String?,
[$collation <https://docs.marklogic.com/fn.substringBefore#collation>
as String]
) as String?
Since all the rest string functions are either return a string or throw
exceptions, I think return an empty string should be a consistent behavior.
On Sep 28, 2015, at 9:12 PM, Mike Carey <[email protected]> wrote:
Yes, and the Marklogic entry reminded me - the answer should probably be
modeled (for us) after XQuery - where the answers are fully spelled out
already (having been debated by a group of smart people first and
implemented by a bunch of XQuery engine providers):
http://www.w3.org/TR/xpath-functions-30/#func-substring-before
http://www.w3.org/TR/xpath-functions-30/#func-substring-after
Cheers,
Mike
On 9/28/15 6:10 PM, Taewoo Kim wrote:
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
Best,
Jianfeng Jia
PhD Candidate of Computer Science
University of California, Irvine
