Re: how to use sh:if

Rules are used to add triples - implementing inference. Your example asked about checking data validity. If you want to classify people based on their height, then, yes, a rule would be the way to go.

I don’t think you need else if. You would simply specify a class for each range of heights. Here is an example of a rule:

ex:Rectangle a rdfs:Class, sh:NodeShape ;
rdfs:label "Rectangle" ;
sh:property  [ sh:path ex:height ;
  sh:datatype xsd:integer ;
  sh:maxCount 1 ;
  sh:minCount 1 ;
  sh:name "height" ; ] ;
sh:property [ sh:path ex:width ;
  sh:datatype xsd:integer ;
  sh:maxCount 1 ;
  sh:minCount 1 ;
  sh:name "width" ; ] ;
sh:rule [ a sh:TripleRule ;
  sh:subject sh:this ;
                sh:predicate rdf:type ;
  sh:object ex:Square ;
  sh:condition [ sh:property [ sh:path ex:width ; sh:equals ex:height ; ] ; ] ; ] .

This rule infers that a rectangle with the equal width and height is a square. You can do something similar attaching rules to :Person class and specifying conditions that will infer the :ShortPerson, :TallPerson :MediumPerson types accordingly.

> On Jul 18, 2021, at 11:30 AM, Joy lix <joylix4112@outlook.com> wrote:
> 
> Hi, Irene, Thank you very much for your reply and detailed code.
> It's been very helpful to me.
> I've also been told to use sh:rule to implement this,  I need to take a closer look at the examples in the SHACL test suite.
> But with respect to sh:if, it would be nice to have a more detailed example in the test set  ,In the SHACL-AF specification, there are sh:if, sh:then, sh:else, So what about multiple branches like elseif?  Is it necessary to add sh:elseif?  
> 
> Kind regards,
> Joylix
> 
> 发件人: Irene Polikoff <irene@topquadrant.com <mailto:irene@topquadrant.com>>
> 发送时间: 2021年7月17日 7:39
> 收件人: Joy lix <joylix4112@outlook.com <mailto:joylix4112@outlook.com>>
> 抄送: public-shacl@w3.org <mailto:public-shacl@w3.org> <public-shacl@w3.org <mailto:public-shacl@w3.org>>
> 主题: Re: how to use sh:if
>  
> Sorry was too quick to respond and made a couple of typos in the first option. 
> 
> Use the following:
> 
> 
>> :TallPerson a owl:Class, sh:NodeShape;
>> sh:property [sh:path :hasHeight;
>>                    sh:datatype xsd:integer;
>>                    sh:minInclusive 185;]
>> ...
>> .
> 
> Or
> 
> :TallPerson a owl:Class, sh:NodeShape;
> sh:property :TallPerson-height;
> ...
> .
> Together With
> 
>> :TallPerson-height a  sh:PropertyShape;
>> sh:path :hasHeight;
>> sh:datatype xsd:integer;
>> sh:minInclusive 185;
>> .
> 
> Or just the property shape with target
> 
> 
>> :TallPerson-height a  sh:PropertyShape;
> Sh:target :TallPerson
>> sh:path :hasHeight;
>> sh:datatype xsd:integer;
>> sh:minInclusive 185;
>> .
> 
>> On Jul 16, 2021, at 1:56 PM, Irene Polikoff <irene@topquadrant.com <mailto:irene@topquadrant.com>> wrote:
>> 
>> You do not need to use sh:if for this example.
>> 
>> Simply do:
>> 
>> :ShortPerson a owl:Class, sh:NodeShape;
>> sh:path :hasHeight;
>> sh:datatype xsd:integer;
>> sh:maxInclusive 155 ;
>> .
>> 
>> :MediumPerson a owl:Class, sh:NodeShape;
>> sh:path :hasHeight;
>> sh:minExclusive 155;
>> sh:datatype xsd:integer;
>> sh:maxExclusive 185;
>> .
>> 
>> :TallPerson a owl:Class, sh:NodeShape;
>> sh:path :hasHeight;
>> sh:datatype xsd:integer;
>> sh:minInclusive 185;
>> .
>> 
>> This will give you a violation message for Bob.
>> 
>> You can also make these property shapes within the node shape if you need to make some statements about other properties of these class members e.g.
>> 
>> :TallPerson a owl:Class, sh:NodeShape;
>> sh:property [sh:path :hasHeight;
>>                    sh:datatype xsd:integer;
>>                    sh:minInclusive 185;]
>> ...
>> .
>> 
>>> On Jul 16, 2021, at 3:28 AM, Joy lix <joylix4112@outlook.com <mailto:joylix4112@outlook.com>> wrote:
>>> 
>>> Dear all: 
>>>  
>>>       I'm not very clear about the use of sh:if, The examples given in the SHACL-AF specification are relatively simple so I don't understand them very well. 
>>> Consider the following example:
>>>  
>>> if someone.height>180 then 
>>>        someone is tallPerson
>>> else if someone.height>155 then 
>>>        someone is mediumPerson
>>> else
>>>        someone is shortPerson
>>>  
>>> How do I present it use sh:if in a shacl shape file?
>>> Can the SHACL validation engine give an violation message for the following data files? 
>>>          :bob a :Person ;
>>>                  :hasHeight 185 ;
>>>                  a :shortPerson .
>>> Because Bob, by definition, should be a tallPerson.
>>>  
>>> Thank you for your help!
>>>  
>>> Kind regards,
>>> Joylix