Shapeshift reference

Experimental: this can change at any time

Shapeshift is experimental. The language, the shifty shape commands, the shifty.experimental.shapeshift Python module, and the shifty-experimental Rust crate can change in any release, without a deprecation period. Pin the Shifty version if you depend on them.

The SHACL that shifty shape export writes for each construct, the reserved words, and the commands. The Shapeshift language explains the constructs.

Constructs in SHACL

Targets

Shapeshift	SHACL
for every C	sh:targetClass C
for every node with p	sh:targetSubjectsOf p
for every value of p	sh:targetObjectsOf p
for node n	sh:targetNode n
for sparql "..."	sh:target [ a sh:SPARQLTarget ; sh:select "..." ]
for every node matching S	a SPARQL target over every node, with sh:or ( [ sh:not S ] shape ). Not SHACL Core: export --core refuses it.

Fields

A field is a property shape on its path. A shape with a single field is exported as that property shape.

Shapeshift	SHACL
p required, p at least n	sh:minCount 1, sh:minCount n
p at most n	sh:maxCount n
p exactly n, p between a and b	sh:minCount and sh:maxCount
p optional	sh:maxCount 1
p each T	the test T on the property shape
p at least n is T, p at least n matches S	sh:qualifiedValueShape T ; sh:qualifiedMinCount n
p at most n is T	sh:qualifiedValueShape T ; sh:qualifiedMaxCount n
p exactly n is T	sh:qualifiedMinCount n ; sh:qualifiedMaxCount n
p below q, p up to q	sh:lessThan q, sh:lessThanOrEquals q
p same as q, p different from q	sh:equals q, sh:disjoint q
p unique language	sh:uniqueLang true

Tests

Shapeshift	SHACL
a C	sh:class C
a C or D	sh:or ( [ sh:class C ] [ sh:class D ] )
matches S	sh:node S (sh:property S when S is a single field)
{ lines }	a blank-node shape
one of x y	sh:in ( x y )
string, integer, …, datatype D	sh:datatype xsd:string, …, sh:datatype D
iri, literal, blank	sh:nodeKind sh:IRI, sh:Literal, sh:BlankNode
length n	sh:minLength n ; sh:maxLength n
length from a to b, length from a, length up to b	sh:minLength a ; sh:maxLength b, sh:minLength a, sh:maxLength b
from a, up to b	sh:minInclusive a, sh:maxInclusive b
above a, below b	sh:minExclusive a, sh:maxExclusive b
from a to b, above a below b, …	both bounds
pattern "re" flags "i"	sh:pattern "re" ; sh:flags "i"
language "en" "de"	sh:languageIn ( "en" "de" )

On a line, is T tests the node itself. is a C puts sh:class C on the shape, and is one of ex:x requires that exact node.

Literals

Shapeshift	RDF
"text", "text"@en	"text", "text"@en
3, 1.5, 1e3	xsd:integer, xsd:decimal, xsd:double
true, false	xsd:boolean
2024-01-31	"2024-01-31"^^xsd:date
2024-01-31T08:00:00Z	"2024-01-31T08:00:00Z"^^xsd:dateTime
08:00:00	"08:00:00"^^xsd:time

Paths

Shapeshift	SHACL
p/q	( p q )
p or q	[ sh:alternativePath ( p q ) ]
^p	[ sh:inversePath p ]
p*, p?	[ sh:zeroOrMorePath p ], [ sh:zeroOrOnePath p ]
p+	( p [ sh:zeroOrMorePath p ] )
path name = ..., name(args)	the path, substituted where it is used

Names, groups, and frames

Shapeshift	SHACL
shape s { ... } with base <b>	<b s>: a sh:NodeShape, or a sh:PropertyShape when it has one field
name: line in shape s	a property shape <b s.name>
s alone on a line	sh:node s
is T on a line	the test T on the shape
s.name on a line	sh:property <b s.name>
p { name: C }	sh:qualifiedValueShape [ sh:class C ] ; sh:qualifiedMinCount 1 ; sh:qualifiedMaxCount 1
row C required, row C optional	only sh:qualifiedMinCount 1, only sh:qualifiedMaxCount 1
any of, exactly one of, none of	sh:or, sh:xone, sh:not
at least n of	sh:or over the combinations
at most n of	sh:not of at least n+1 of
when C then B	sh:or ( [ sh:not C ] B )
template(args)	a shape for each distinct argument list, with shapeshift:expands "template(args)"

Annotations

Shapeshift	SHACL
doc "..."	rdfs:comment on a shape, sh:description on a line
message "..."	sh:message
severity info, warning, violation	sh:severity sh:Info, sh:Warning, sh:Violation
only these properties	sh:closed true ; sh:ignoredProperties ( rdf:type )

An export flags what other SHACL engines need to know, on the file’s owl:Ontology node:

• shapeshift:recursive true when a shape refers to itself.

• shapeshift:shapeTargets or shapeshift:sparqlTargets when it uses those targets.

Reserved words

These words are keywords and cannot name a shape, a path, or a parameter:

a above and any as at base below between blank datatype different doc each
every exactly false flags for from import iri is language least length
literal matches matching message most node none of one only optional or
path pattern prefix properties required same self severity shape sparql
then these to true unique up value when with

Datatype words, such as string and integer, aren’t reserved. Where a test goes, though, they always mean the xsd datatype. A shape named string is reached only with matches string.

Commands

shifty shape works on .shm files. Run shifty shape <command> --help for every option.

Command	Does
check FILE	Parse, resolve imports, and build. Prints diagnostics; exits 1 on an error. --format json for editors and CI.
build FILE	Build and print a summary, or the compiled schema as JSON.
fmt FILE	Print the file in the standard layout, keeping comments and docs. -w rewrites it; --check exits 1 if it is not formatted.
export FILE	Write the shapes as SHACL Turtle. --core refuses what SHACL Core cannot express; -o writes to a file.
validate FILE -d DATA	Validate data and report failures against the lines of the file. -d repeats; exits 1 if the data does not conform.
imports FILE	List the import closure.
explain FILE SHAPE	Show one shape’s source, algebra, and targets.
repl	An interactive session: define shapes, load data, validate, save.

Every command that reads imports (all but fmt and repl) takes:

• --map IRI=PATH, to read an RDF import from a local file.

• --fetch, to download imports that aren’t mapped.

Editors

• Tree-sitter. crates/experimental/tree-sitter-shapeshift is a grammar for .shm, with highlighting queries. Rust code reaches it as shifty_experimental::shapeshift::grammar, with the tree-sitter feature.

• Pygments. docs/_ext/shapeshift_lexer.py registers the shapeshift and shm languages. It highlights these pages.