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Re: proposed user-friendly syntax for SHACL

From: Irene Polikoff <irene@topquadrant.com>
Date: Thu, 07 Apr 2016 19:47:58 -0400
To: Holger Knublauch <holger@topquadrant.com>, <public-data-shapes-wg@w3.org>
Message-ID: <D32C69C1.99ECA%irene@topquadrant.com>
Yes, I have to say I didn’t find it to be user friendly at all.

May be a “compact syntax”?

Irene 





On 4/7/16, 7:35 PM, "Holger Knublauch" <holger@topquadrant.com> wrote:

>Peter, maybe this should be wrapped into an ISSUE so that it gets
>discussed properly?
>
>I am not against such a syntax. It may have its place in academic papers
>etc, and cover scenarios where space is scarce and Turtle snippets would
>be too verbose. It could potentially become a stand-alone deliverable of
>the WG, assuming this effort doesn't take away more critical resources.
>
>At the same time, I believe the label "User-Friendly" is not appropriate
>here. A user-friendly syntax should be limited to easy-to-type
>characters, ideally ASCII. In your email I am not even sure that the
>characters were correctly transmitted. Maybe call it "Symbolic" Syntax?
>(Or LaTeX-friendly syntax :) )
>
>Holger
>
>
>On 1/04/2016 23:02, Peter F. Patel-Schneider wrote:
>> 		A User-Friendly Syntax for Core SHACL
>>
>>
>> This is a user-friendly syntax for the core of SHACL that tries to align
>> directly with my SHACL RDF syntax.
>>
>>
>> 	Example    				Description
>>
>> ∈ ex:Person ⊩ |≤27|			# there are at most 27 people
>> ¹ex:child ⊩ ∋ ex:john			# child subjects include John
>> ¹ex:child ⊩ ∈ ex:Person ∧ IRI		# ... are people and not blank
>> ex:child² ⊩ ∈ ex:Person 		# child objects are people
>> ∈ ex:Patriot ⊩ ⋹ ex:Citizen		# patriots are directly citizens
>> ex:password² ⊩ ^^xs:string ∧ ℓ≤24 ∧ ℓ≥8	# passwords are between 8 and
>>24 long
>> ex:age² ⊩ ^^xs:integer ∧ ≥0		# ages are non-negative integers
>> ex:john ⊩ ex:name ∝ "^John.*" ★ 	# John's name starts with "John"
>> ex:mstatus² ⊩ ∈ { ex:single ex:married ex:divorced }
>> 					# three marital statuses only
>> ex:Person ⊩ ex:mstatus ∝ |=1|		# people have one marital status
>> ex:Person ⊩ ex:mstatus ∝ ∋ ex:married → ex:spouse ∝ |≥1|
>> 					# married people have a spouse
>> ex:Person ⊩ ex:mstatus ∝ ∋ ex:single → ex:spouse ∝ |≤0|
>> 					# single people don't have a spouse
>> ∈ ex:Person ⊩ ex:spouse ∅ ex:child ∧	# people can't marry their children
>> 	ex:child ex:age ≤ ex:age ∧	# ... are older than their children
>> 	ex:age ≤ ex:child⁻¹ ex:age ∧	# ... are younger than their parents
>> 	ex:child⁻¹ ex:child ∝ |≤9| ∧	# ... have at most 8 siblings
>> 	ex:name ∝ ∈ rdf:langString ∧	# ... names are lang-tagged strings
>> 	ex:name ∝ ➀			# ... have only one name per language
>> ∈ ex:Person ⊩
>>    ( ( ex:spouse ∝ |≤0| → ex:mstatus ∝ ( |≥1| ∧ ∈{ex:single
>>ex:divorced} ) ) ∖
>>      ( ex:spouse ∝ |≤1| → ex:mstatus ∝ ( |≥1| ∧ ∈{ex:married} ) ) ∖
>>      |≤3| ∖ )      		# people with no spouse are single or divorced
>> 				# people with one spouse are married
>> 				# and there are at most three people left over
>> ∈ ex:Isolated ⊩ ⟦ rdf:type ⟧		# isolated nodes have only types
>> ∈ ex:nonIsolated ⊩ ¬ ⟦ rdf:type ⟧	# non-isolated nodes have other values
>> sh:partShape ≡ (IRI ∨ sh:inverse ∝ IRI)	# parts are properties or
>>inverses
>> sh:pathShape ≡ ∈ sh:path ⊩ ( sh:partShape ∨ ⦇ sh:partShape ⦈ )
>> 					# paths are parts or lists of parts
>>
>>
>> 	Grammar					Meaning
>>
>> shaclDoc  ::= ( prefixID | definition ) *
>>
>> prefixID  ::= '@prefix' prefixName ':' IRI
>>
>> definition::= name '≡' shape			# refer to shape by name
>> 	    | name '≡' scopedShape		# refer to shape by name
>>
>> scopedShape ::= scope ( '∪' scope )* '⊩' shape
>> 		# set of all nodes in any scope validates against shape
>>
>> scope	  ::= value				# the value
>> 	    | '∈' class				# SHACL instances of class
>> 	    | '¹' property			# subjects of property
>> 	    | property '²'			# objects of property
>> 	    | '¹' '?'				# all subjects
>> 	    | '?' '²'				# all objects
>>
>> shape	  ::= ( filter ( '∧' filter )* '→' )? component ( '∧' component )*
>> 		# set of nodes that validate against all filters
>> 		# validates against each component
>>
>> filter	  ::= component				# nodes that validate vs shape
>>
>> component ::= name				# validate against named shape
>> 	    | '¬' component			# doesn't validate ag. comp.
>> 	    | '∈' class ( '∪' class )*		# SHACL instance of some class
>> 	    | '^^' datatype ( '∪' datatype )*	# has one of datatypes
>> 	    | '∈' '{' value* '}'		# is one of values
>> 	    | '⋹' class  			# has rdf:type of class
>> 	    | 'ℓ' '≤' nonnegativeInteger 	# maximum string length
>> 	    | 'ℓ' '≥' nonnegativeInteger 	# minimum string length
>> 	    | '>' literal			# exclusive minimum
>> 	    | '≥' literal			# inclusive minimum
>> 	    | '<' literal			# exclusive maximum
>> 	    | '≤' literal			# inclusive maximum
>> 	    | 'IRI' | 'Literal' | 'BlankNode'	# kind of node
>> 	    | regex '★' ( string )?		# matches pattern (with flags)
>> 	    | path '=' path			# path values the same
>> 	    | path '∅' path			# path values disjoint
>> 	    | path '<' path			# path1 values < path2 values
>> 	    | path '≤' path			# path1 values ≤ path2 values
>> 	    | path '∝' component		# path values in shape
>> 	    | '⦇' shape '⦈'			# list members in shape
>> 	    | '⟦' pathpart * '⟧'		# no other property has values
>> 	    | '∋' value				# set contains value
>> 	    | '|' '≥' nonnegativeInteger '|'	# minimum size of set
>> 	    | '|' '≤' nonnegativeInteger '|'	# maximum size of set
>> 	    | '|' '=' nonnegativeInteger '|'	# exact size of set
>> 	    | '➀'				# only one value per language
>> 	    | '(' shape ')'			# validate against shape
>> 	    | '(' component ('∨'component)+ ')'	# validate against one or more
>> 	    | '(' ( component '∖' ) + ')'	# partition - see below
>> 		# The initial remnant is the entire set being validated.
>> 		# The next remnant is the subset of the current one that fails
>> 		# to validate against the filter of the respective component.
>> 		# The final remnant is empty.
>> 		# Each remnant validates against the respective component.
>> ⦅
>>
>> path	  ::= pathpart +			# composition
>> pathpart  ::= property
>> 	    | property '⁻¹'			# inverse of property
>>
>> class	  ::= name				# a class
>> datatype  ::= name				# a datatype
>> property  ::= name				# a property
>> value	  ::= name | literal			# object
>>
>> regex	  ::= string				# regular expression
>>
>> name      ::= qname			# NOTE: no <IRI> here, just qnames
>> qname	  ::= prefixName ':' name
>> IRI	  ::= '<' ucharacter '>'
>>
>> prefixName		as per Turtle
>> name			as per Turtle
>> literal   		as per Turtle
>>
>> string			as per usual
>> nonnegativeInteger	as per usual
>>
>>
>>
>> 	Possible Tweaks
>>
>> It would be possible to modify the syntax to come up with a more
>>standard
>> treatment of conjunction, disjunction, and negation but that syntax
>>would
>> not align as closely with the RDF syntax.
>
>
Received on Thursday, 7 April 2016 23:48:36 UTC

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