question

On 29 July 2015 at 17:34, Eliot Kimber <ekimber at contrext.com> wrote: > I believe you need to use the "castable as" or "instance of" operators to > determine the type, e.g.: > > let $typeName := > if ($somevar castable as xs:integer) > then 'integer' > else if ($somevar castable as xs:string) > then 'string' > else 'unknown type' > > Or something close to that. There is also "instance of", which might be > > I also found this paper, which might be interesting: > > http://www.balisage.net/Proceedings/vol8/html/Holstege01/BalisageVol8-Holst > ege01.html > > Cheers, > > E. > ---- > Eliot Kimber, Owner > Contrext, LLC > http://contrext.com > > > > > On 7/29/15, 9:54 AM, "Rob Stapper" > <basex-talk-bounces at mailman.uni-konstanz.de on behalf of > r.stapper at lijbrandt.nl> wrote: > >>Hello, >> >>I must be overlooking something, so excuses in advance, but: How can I >>retrieve the datatype of a variable? >> >>TIA, >>Rob Stapper >> >> >> >>________________________________________ >> >> >> >> >> <https://www.avast.com/antivirus> >> >> >> >> Dit e-mailbericht is gecontroleerd op virussen met Avast >>antivirussoftware. >> >>www.avast.com <https://www.avast.com/antivirus> >> >> >> > >

r.stapper at lijbrandt.nl> wrote: >Hello, > >I must be overlooking something, so excuses in advance, but: How can I >retrieve the datatype of a variable? > >TIA, >Rob Stapper > > > >________________________________________ > > > > > <https://www.avast.com/antivirus> > > > > Dit e-mailbericht is gecontroleerd op virussen met Avast >antivirussoftware. > >www.avast.com <https://www.avast.com/antivirus> > > >

On 7/29/15, 10:42 AM, "Florent Georges" <fgeorges at gmail.com on behalf of lists at fgeorges.org> wrote: >Hi, > >That would base the type annotation on the lexical value. For >instance, the string '0' would be labelled as "integer" (given you >test for xs:integer before xs:string): > >let $var := '0' >return > if ( $var castable as xs:integer ) > then 'integer' > else if ( $var castable as xs:string ) > then 'string' > else > 'unknown type' >(: -> 'integer' :) > >The operator "instance of" would solve that problem. But then, for >that purpose, there is the "typeswitch" instruction: > >typeswitch ( '0' ) > case xs:integer return > 'integer' > case xs:string return > 'string' > default return > 'unknown type' >(: -> 'string' :) > >Regards, > >-- >Florent Georges >http://fgeorges.org/ >http://h2oconsulting.be/ > > >On 29 July 2015 at 17:34, Eliot Kimber <ekimber at contrext.com> wrote: >> I believe you need to use the "castable as" or "instance of" operators >>to >> determine the type, e.g.: >> >> let $typeName := >> if ($somevar castable as xs:integer) >> then 'integer' >> else if ($somevar castable as xs:string) >> then 'string' >> else 'unknown type' >> >> Or something close to that. There is also "instance of", which might be >> >> I also found this paper, which might be interesting: >> >> >>http://www.balisage.net/Proceedings/vol8/html/Holstege01/BalisageVol8-Hol >>st >> ege01.html >> >> Cheers, >> >> E. >> ---- >> Eliot Kimber, Owner >> Contrext, LLC >> http://contrext.com >> >> >> >> >> On 7/29/15, 9:54 AM, "Rob Stapper" >> <basex-talk-bounces at mailman.uni-konstanz.de on behalf of >> r.stapper at lijbrandt.nl> wrote: >> >>>Hello, >>> >>>I must be overlooking something, so excuses in advance, but: How can I >>>retrieve the datatype of a variable? >>> >>>TIA, >>>Rob Stapper >>> >>> >>> >>>________________________________________ >>> >>> >>> >>> >>> <https://www.avast.com/antivirus> >>> >>> >>> >>> Dit e-mailbericht is gecontroleerd op >>>virussen met Avast >>>antivirussoftware. >>> >>>www.avast.com <https://www.avast.com/antivirus> >>> >>> >>> >> >> >

Van: Eliot Kimber [mailto:ekimber at contrext.com] Verzonden: woensdag 29 juli 2015 19:56 Aan: Florent Georges CC: Rob Stapper; BaseX Onderwerp: Re: [basex-talk] question I am happy to be corrected. Cheers, E. ---- Eliot Kimber, Owner Contrext, LLC http://contrext.com On 7/29/15, 10:42 AM, "Florent Georges" <fgeorges at gmail.com on behalf of lists at fgeorges.org> wrote: >Hi, > >That would base the type annotation on the lexical value. For >instance, the string '0' would be labelled as "integer" (given you test >for xs:integer before xs:string): > >let $var := '0' >return > if ( $var castable as xs:integer ) > then 'integer' > else if ( $var castable as xs:string ) > then 'string' > else > 'unknown type' >(: -> 'integer' :) > >The operator "instance of" would solve that problem. But then, for >that purpose, there is the "typeswitch" instruction: > >typeswitch ( '0' ) > case xs:integer return > 'integer' > case xs:string return > 'string' > default return > 'unknown type' >(: -> 'string' :) > >Regards, > >-- >Florent Georges >http://fgeorges.org/ >http://h2oconsulting.be/ > > >On 29 July 2015 at 17:34, Eliot Kimber <ekimber at contrext.com> wrote: >> I believe you need to use the "castable as" or "instance of" >>operators to determine the type, e.g.: >> >> let $typeName := >> if ($somevar castable as xs:integer) >> then 'integer' >> else if ($somevar castable as xs:string) >> then 'string' >> else 'unknown type' >> >> Or something close to that. There is also "instance of", which might >> be >> >> I also found this paper, which might be interesting: >> >> >>http://www.balisage.net/Proceedings/vol8/html/Holstege01/BalisageVol8- >>Hol >>st >> ege01.html >> >> Cheers, >> >> E. >> ---- >> Eliot Kimber, Owner >> Contrext, LLC >> http://contrext.com >> >> >> >> >> On 7/29/15, 9:54 AM, "Rob Stapper" >> <basex-talk-bounces at mailman.uni-konstanz.de on behalf of >> r.stapper at lijbrandt.nl> wrote: >> >>>Hello, >>> >>>I must be overlooking something, so excuses in advance, but: How can >>>I retrieve the datatype of a variable? >>> >>>TIA, >>>Rob Stapper >>> >>> >>> >>>________________________________________ >>> >>> >>> >>> >>> <https://www.avast.com/antivirus> >>> >>> >>> >>> Dit e-mailbericht is gecontroleerd op >>>virussen met Avast antivirussoftware. >>> >>>www.avast.com <https://www.avast.com/antivirus> >>> >>> >>> >> >> > --- Dit e-mailbericht is gecontroleerd op virussen met Avast antivirussoftware. https://www.avast.com/antivirus

On Thu, Jul 30, 2015 at 9:41 AM, Rob Stapper <r.stapper at lijbrandt.nl> wrote: > Eliot, Florent, > > Thank you both for your reaction. > > I've been thinking about the typeswitch-command too but it feels weird: I > have this variable, inside XQuery its type is known but for retrieving it I > have to go through all types and ask XQuery if it is this one. > I hoped for a more direct solution. > > I've been thinking about the inspect-function too but that one is more mend > for documentation-purposes and I guess performance is an issue there. > > Thanx again, > > Rob > > > -----Oorspronkelijk bericht----- > Van: Eliot Kimber [mailto:ekimber at contrext.com] > Verzonden: woensdag 29 juli 2015 19:56 > Aan: Florent Georges > CC: Rob Stapper; BaseX > Onderwerp: Re: [basex-talk] question > > I am happy to be corrected. > > Cheers, > > E. > ---- > Eliot Kimber, Owner > Contrext, LLC > http://contrext.com > > > > > On 7/29/15, 10:42 AM, "Florent Georges" <fgeorges at gmail.com on behalf of > lists at fgeorges.org> wrote: > >>Hi, >> >>That would base the type annotation on the lexical value. For >>instance, the string '0' would be labelled as "integer" (given you test >>for xs:integer before xs:string): >> >>let $var := '0' >>return >> if ( $var castable as xs:integer ) >> then 'integer' >> else if ( $var castable as xs:string ) >> then 'string' >> else >> 'unknown type' >>(: -> 'integer' :) >> >>The operator "instance of" would solve that problem. But then, for >>that purpose, there is the "typeswitch" instruction: >> >>typeswitch ( '0' ) >> case xs:integer return >> 'integer' >> case xs:string return >> 'string' >> default return >> 'unknown type' >>(: -> 'string' :) >> >>Regards, >> >>-- >>Florent Georges >>http://fgeorges.org/ >>http://h2oconsulting.be/ >> >> >>On 29 July 2015 at 17:34, Eliot Kimber <ekimber at contrext.com> wrote: >>> I believe you need to use the "castable as" or "instance of" >>>operators to determine the type, e.g.: >>> >>> let $typeName := >>> if ($somevar castable as xs:integer) >>> then 'integer' >>> else if ($somevar castable as xs:string) >>> then 'string' >>> else 'unknown type' >>> >>> Or something close to that. There is also "instance of", which might >>> be >>> >>> I also found this paper, which might be interesting: >>> >>> >>>http://www.balisage.net/Proceedings/vol8/html/Holstege01/BalisageVol8- >>>Hol >>>st >>> ege01.html >>> >>> Cheers, >>> >>> E. >>> ---- >>> Eliot Kimber, Owner >>> Contrext, LLC >>> http://contrext.com >>> >>> >>> >>> >>> On 7/29/15, 9:54 AM, "Rob Stapper" >>> <basex-talk-bounces at mailman.uni-konstanz.de on behalf of >>> r.stapper at lijbrandt.nl> wrote: >>> >>>>Hello, >>>> >>>>I must be overlooking something, so excuses in advance, but: How can >>>>I retrieve the datatype of a variable? >>>> >>>>TIA, >>>>Rob Stapper >>>> >>>> >>>> >>>>________________________________________ >>>> >>>> >>>> >>>> >>>> <https://www.avast.com/antivirus> >>>> >>>> >>>> >>>> Dit e-mailbericht is gecontroleerd op >>>>virussen met Avast antivirussoftware. >>>> >>>>www.avast.com <https://www.avast.com/antivirus> >>>> >>>> >>>> >>> >>> >> > > > > --- > Dit e-mailbericht is gecontroleerd op virussen met Avast antivirussoftware. > https://www.avast.com/antivirus >

Van: Christian Grün [mailto:christian.gruen at gmail.com] Verzonden: donderdag 30 juli 2015 9:55 Aan: Rob Stapper CC: Eliot Kimber; Florent Georges; BaseX Onderwerp: Re: [basex-talk] question Hi Rob, In that regard, XQuery is pretty similar to many other programming languages. Think e.g. of the following Java code: public JLabel label = new JLabel(); What do you think is the "data type" of the variable named "label", and how would you like to deal with it in Java? Cheers, Christian On Thu, Jul 30, 2015 at 9:41 AM, Rob Stapper <r.stapper at lijbrandt.nl> wrote: > Eliot, Florent, > > Thank you both for your reaction. > > I've been thinking about the typeswitch-command too but it feels > weird: I have this variable, inside XQuery its type is known but for > retrieving it I have to go through all types and ask XQuery if it is this one. > I hoped for a more direct solution. > > I've been thinking about the inspect-function too but that one is more > mend for documentation-purposes and I guess performance is an issue there. > > Thanx again, > > Rob > > > -----Oorspronkelijk bericht----- > Van: Eliot Kimber [mailto:ekimber at contrext.com] > Verzonden: woensdag 29 juli 2015 19:56 > Aan: Florent Georges > CC: Rob Stapper; BaseX > Onderwerp: Re: [basex-talk] question > > I am happy to be corrected. > > Cheers, > > E. > ---- > Eliot Kimber, Owner > Contrext, LLC > http://contrext.com > > > > > On 7/29/15, 10:42 AM, "Florent Georges" <fgeorges at gmail.com on behalf > of lists at fgeorges.org> wrote: > >>Hi, >> >>That would base the type annotation on the lexical value. For >>instance, the string '0' would be labelled as "integer" (given you >>test for xs:integer before xs:string): >> >>let $var := '0' >>return >> if ( $var castable as xs:integer ) >> then 'integer' >> else if ( $var castable as xs:string ) >> then 'string' >> else >> 'unknown type' >>(: -> 'integer' :) >> >>The operator "instance of" would solve that problem. But then, for >>that purpose, there is the "typeswitch" instruction: >> >>typeswitch ( '0' ) >> case xs:integer return >> 'integer' >> case xs:string return >> 'string' >> default return >> 'unknown type' >>(: -> 'string' :) >> >>Regards, >> >>-- >>Florent Georges >>http://fgeorges.org/ >>http://h2oconsulting.be/ >> >> >>On 29 July 2015 at 17:34, Eliot Kimber <ekimber at contrext.com> wrote: >>> I believe you need to use the "castable as" or "instance of" >>>operators to determine the type, e.g.: >>> >>> let $typeName := >>> if ($somevar castable as xs:integer) >>> then 'integer' >>> else if ($somevar castable as xs:string) >>> then 'string' >>> else 'unknown type' >>> >>> Or something close to that. There is also "instance of", which might >>> be >>> >>> I also found this paper, which might be interesting: >>> >>> >>>http://www.balisage.net/Proceedings/vol8/html/Holstege01/BalisageVol8 >>>- >>>Hol >>>st >>> ege01.html >>> >>> Cheers, >>> >>> E. >>> ---- >>> Eliot Kimber, Owner >>> Contrext, LLC >>> http://contrext.com >>> >>> >>> >>> >>> On 7/29/15, 9:54 AM, "Rob Stapper" >>> <basex-talk-bounces at mailman.uni-konstanz.de on behalf of >>> r.stapper at lijbrandt.nl> wrote: >>> >>>>Hello, >>>> >>>>I must be overlooking something, so excuses in advance, but: How can >>>>I retrieve the datatype of a variable? >>>> >>>>TIA, >>>>Rob Stapper >>>> >>>> >>>> >>>>________________________________________ >>>> >>>> >>>> >>>> >>>> <https://www.avast.com/antivirus> >>>> >>>> >>>> >>>> Dit e-mailbericht is gecontroleerd op >>>>virussen met Avast antivirussoftware. >>>> >>>>www.avast.com <https://www.avast.com/antivirus> >>>> >>>> >>>> >>> >>> >> > > > > --- > Dit e-mailbericht is gecontroleerd op virussen met Avast antivirussoftware. > https://www.avast.com/antivirus > --- Dit e-mailbericht is gecontroleerd op virussen met Avast antivirussoftware. https://www.avast.com/antivirus

> If I was programming in Java I guess I want Java to return the string: "JLabel" probably combined with the URI of the source were JLabel is defined.

Van: Eliot Kimber [mailto:ekimber at contrext.com] Verzonden: woensdag 29 juli 2015 17:35 Aan: Rob Stapper; BaseX Onderwerp: Re: [basex-talk] question I believe you need to use the "castable as" or "instance of" operators to determine the type, e.g.: let $typeName := if ($somevar castable as xs:integer) then 'integer' else if ($somevar castable as xs:string) then 'string' else 'unknown type' Or something close to that. There is also "instance of", which might be I also found this paper, which might be interesting: http://www.balisage.net/Proceedings/vol8/html/Holstege01/BalisageVol8-Holst ege01.html Cheers, E. ---- Eliot Kimber, Owner Contrext, LLC http://contrext.com On 7/29/15, 9:54 AM, "Rob Stapper" <basex-talk-bounces at mailman.uni-konstanz.de on behalf of r.stapper at lijbrandt.nl> wrote: >Hello, > >I must be overlooking something, so excuses in advance, but: How can I >retrieve the datatype of a variable? > >TIA, >Rob Stapper > > > >________________________________________ > > > > > <https://www.avast.com/antivirus> > > > > Dit e-mailbericht is gecontroleerd op virussen met Avast >antivirussoftware. > >www.avast.com <https://www.avast.com/antivirus> > > > --- Dit e-mailbericht is gecontroleerd op virussen met Avast antivirussoftware. https://www.avast.com/antivirus

Van: Christian Grün [mailto:christian.gruen at gmail.com] Verzonden: donderdag 30 juli 2015 11:14 Aan: Rob Stapper CC: Eliot Kimber; Florent Georges; BaseX Onderwerp: Re: [basex-talk] question > If I was programming in Java I guess I want Java to return the string: "JLabel" probably combined with the URI of the source were JLabel is defined. In that case, you would have to work with the reflection features of Java. In BaseX, the equivalent facility is (as you already guessed) the Inspection Module. However, I wouldn't recommend you to follow this path, as you would soon end up doing all kinds of things with string comparisons. What are you actually trying to attain with the string representation of types? --- Dit e-mailbericht is gecontroleerd op virussen met Avast antivirussoftware. https://www.avast.com/antivirus

> I bit of a complex story but I hope it makes sense to you.

> - say we have a domain: "pears" containing pears and a domain: "apples" containing apples. > - say we define a subset on the "apples"-domain as: "all apples from domain: "apples", except apple: <some_apple_id>, and apple: <some_other_apple_id>" > - say we have a pear form the "pears"-domain with id: <some_pear_id>. > - if I want to test if the apple-subset contains this pear I must check the domain, i.o.w. type, of the pear against the domain, i.o.w. type, of the apple-subset. > If I don't the answer to this question would be: "true", which is wrong. In that case I'm not referring to the apple-domain but to literal everything. And yes, everything also contains this pear. > > I could make the domain-name a part of the identification but that is only possible for my self defined datatypes and not for XQuery's native datatypes. > > > Rob > > -----Oorspronkelijk bericht----- > Van: Christian Grün [mailto:christian.gruen at gmail.com] > Verzonden: donderdag 30 juli 2015 11:14 > Aan: Rob Stapper > CC: Eliot Kimber; Florent Georges; BaseX > Onderwerp: Re: [basex-talk] question > >> If I was programming in Java I guess I want Java to return the string: "JLabel" probably combined with the URI of the source were JLabel is defined. > > In that case, you would have to work with the reflection features of Java. In BaseX, the equivalent facility is (as you already guessed) the Inspection Module. > > However, I wouldn't recommend you to follow this path, as you would soon end up doing all kinds of things with string comparisons. What are you actually trying to attain with the string representation of types? > > > --- > Dit e-mailbericht is gecontroleerd op virussen met Avast antivirussoftware. > https://www.avast.com/antivirus >

Van: Christian Grün [mailto:christian.gruen at gmail.com] Verzonden: donderdag 30 juli 2015 12:52 Aan: Rob Stapper CC: Eliot Kimber; Florent Georges; BaseX Onderwerp: Re: [basex-talk] question > I bit of a complex story but I hope it makes sense to you. Hm. I still don't see why typeswitch wouldn't help as well, but your use case may indeed be too complex to break it down to a few sentences.. ;) But if you think it cannot be solved with static type checks (i.e., with "typeswitch" and "instance of"), you should probably do what has been motivated by Florent, and write a function that gives you the string representation of types )(see e.g. Priscilla Walmsley's solution for atomic types [1]). Do you also need a string representation of function items? Christian [1] http://www.xqueryfunctions.com/xq/functx_atomic-type.html > - say we have a domain: "pears" containing pears and a domain: "apples" containing apples. > - say we define a subset on the "apples"-domain as: "all apples from domain: "apples", except apple: <some_apple_id>, and apple: <some_other_apple_id>" > - say we have a pear form the "pears"-domain with id: <some_pear_id>. > - if I want to test if the apple-subset contains this pear I must check the domain, i.o.w. type, of the pear against the domain, i.o.w. type, of the apple-subset. > If I don't the answer to this question would be: "true", which is wrong. In that case I'm not referring to the apple-domain but to literal everything. And yes, everything also contains this pear. > > I could make the domain-name a part of the identification but that is only possible for my self defined datatypes and not for XQuery's native datatypes. > > > Rob > > -----Oorspronkelijk bericht----- > Van: Christian Grün [mailto:christian.gruen at gmail.com] > Verzonden: donderdag 30 juli 2015 11:14 > Aan: Rob Stapper > CC: Eliot Kimber; Florent Georges; BaseX > Onderwerp: Re: [basex-talk] question > >> If I was programming in Java I guess I want Java to return the string: "JLabel" probably combined with the URI of the source were JLabel is defined. > > In that case, you would have to work with the reflection features of Java. In BaseX, the equivalent facility is (as you already guessed) the Inspection Module. > > However, I wouldn't recommend you to follow this path, as you would soon end up doing all kinds of things with string comparisons. What are you actually trying to attain with the string representation of types? > > > --- > Dit e-mailbericht is gecontroleerd op virussen met Avast antivirussoftware. > https://www.avast.com/antivirus > --- Dit e-mailbericht is gecontroleerd op virussen met Avast antivirussoftware. https://www.avast.com/antivirus