[xquery-talk] Random number generation : requirements

Adam Retter adam.retter at googlemail.com
Wed May 7 11:05:28 PDT 2014


Just to throw in the functions from eXist which are also non-deterministic -

http://www.exist-db.org/exist/apps/fundocs/index.html?action=search&type=name&q=random

Personally I would be more interested in having a good random number
source for generating strong UUIDs, at the moment we just have an
extension function which is a non-deterministic wrapper around some
Java - http://www.exist-db.org/exist/apps/fundocs/index.html?action=search&type=name&q=uuid

On 6 May 2014 18:51, Christian Grün <christian.gruen at gmail.com> wrote:
> And here is the Random Module of BaseX:
>
>   http://docs.basex.org/wiki/Random_Module
>
> Similar to Zorba, most functions are non-deterministic. Is there any
> particular reason why the official random functions need to be
> deterministic?
>
> Hope this helps,
> Christian
>
>
> On Tue, May 6, 2014 at 7:42 PM, Matthias Brantner
> <matthias.brantner at 28msec.com> wrote:
>> Michael
>>
>> Here is the documentation of a module containing functions to generate
>> random numbers or strings with Zorba.
>>
>> http://www.zorba.io/documentation/latest/modules/zorba/xdm/atomic/random
>>
>> Please note that some functions are using Zorba's nondeterministic annotation.
>> Also note, that there is one function that creates uuids returned as string.
>>
>> The functions have proven themselves useful in plenty of scenarios like
>> password or web session token generation.
>>
>> I hope you find this module useful.
>>
>> Matthias
>>
>> On May 6, 2014, at 9:53 AM, Michael Kay <mike at saxonica.com> wrote:
>>
>>> The W3C WGs are looking at the idea of introducing a random-number function of some kind in XPath 3.1. The challenge of course is making this both usable and a pure function with no side-effects. We have various design ideas which we need to test against requirements.
>>>
>>> If you have any applications that use or need such a function, please could I have a brief description of the way it uses random numbers, e.g. just wanting a single random number, a random permutation of 52 integers, an arbitrary sequence of random numebrs for test data generation, etc.
>>>
>>> If you're currently using the EXSLT random-sequence() function, please share your experience with it.
>>>
>>> Michael Kay
>>> Saxonica
>>> _______________________________________________
>>> talk at x-query.com
>>> http://x-query.com/mailman/listinfo/talk
>>
>>
>> _______________________________________________
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>
> _______________________________________________
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Adam Retter

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