Feature support

Legend: ✅ supported · ⚠️ partial or gated · ❌ unsupported.

SHACL Core

Feature	Status	Notes
Node & property shapes	✅
Targets — targetNode, targetClass, targetSubjectsOf, targetObjectsOf, implicit class	✅
Cardinality — minCount, maxCount	✅
Value type — datatype, nodeKind, class	✅
Range — min/maxInclusive, min/maxExclusive	✅	numeric, date/time, and duration ordering
String — minLength, maxLength, pattern (+ flags), languageIn, uniqueLang	✅
Logical — and, or, not, xone	✅
Shape-based — node, property, qualifiedValueShape (+ counts, qualifiedValueShapesDisjoint)	✅
Property pairs — equals, disjoint, lessThan, lessThanOrEquals	✅	on node and property shapes
Other — closed (+ ignoredProperties), hasValue, in	✅
Paths — predicate, inverse, sequence, alternative, zeroOrMore, oneOrMore, zeroOrOne	✅
severity, deactivated, message	✅

SHACL-AF (Advanced Features)

Feature	Status	Notes
Rules — sh:TripleRule, sh:SPARQLRule (CONSTRUCT)	✅	forward-chained to a fixed point, honouring sh:order / sh:condition
Node expressions — sh:this, constants, sh:path, sh:filterShape, sh:intersection, sh:union, function application	✅
SPARQL targets — sh:target + sh:select	✅
SPARQL constraints — sh:sparql (sh:select / sh:ask)	✅	native execution with Spareval fallback
Custom constraint components — sh:parameter + sh:validator / sh:nodeValidator / sh:propertyValidator	✅	optional params, simple and complex $PATH, report path
Expression constraints — sh:expression	✅
SHACL functions — sh:SPARQLFunction in node expressions	✅	full data-graph access
SHACL functions — sh:SPARQLFunction called from SPARQL (sh:sparql, CONSTRUCT, dash:expression)	⚠️	evaluated as pure functions of their arguments; a body that reads the data graph is gated — see Partial support
JavaScript — sh:js*, sh:JSFunction	❌	no JS engine

Recursion and semantics

Feature	Status	Notes
Stratified recursive shapes	✅	greatest fixed point for validation, least for inference, per stratum
Non-stratifiable schemas (a cycle through negation)	❌	diagnosed and refused, never guessed

See Recursion and stratification for what those fixed points mean and why a non-stratifiable schema has no answer to give.

Partial support

A ⚠️ feature is one where Shifty can produce an answer but cannot guarantee it is the right one. Rather than pick silently, it lets you choose what happens, through on_unsupported — EngineOptions in Rust, and a keyword on validate, validate_algebra, infer, and PreparedValidator in Python:

"ignore" (default)

Best effort. A graph-reading function called from a SPARQL context is evaluated over an empty dataset, so the result may be wrong.

"error"

Refuse. The unsupported construct surfaces as a failure instead of a silent wrong answer.

conforms, report, text = shifty.validate(data, shapes, on_unsupported="error")

Invalid shapes diagnostics are separate from this policy. A malformed SHACL constraint or rule, including malformed SPARQL or an unresolved query prefix, is always rejected before validation or inference starts; it is never lowered as an absent feature.

The default is "ignore" for compatibility with existing pipelines, but if you are going to act on the result, "error" is the setting you want: it converts an unreliable answer into a visible one.

Evidence and repair coverage

Validation status is exact for every supported feature. The explanations are not always available: a sh:sparql constraint is opaque to evidence and blocked for repair, because an arbitrary query cannot be inverted. The complete list of these cases is in Evidence reference under “Opaque and blocked evidence”, and repair’s blocking reasons are in Repair reference.