Twirl is a SPIN constraint validator that is meant to be a drop-in replacement for the SPIN RDF.

Twirl implementation is based on plain SPARQL execution and does not depend on Jena's internals, which leads to issues in SPIN RDF:

• Behavior change between Jena 3.0.1 and 3.16.0-SNAPSHOT
• SPIN constraint validation differs on 3.0.1 and 3.16.0-SNAPSHOT

Twirl has the following limitations:

• ASK constraints are not supported (only CONSTRUCT)
• constraint violation fixes are not supported
• SPIN functions are not supported
• SPIN rules are not supported

Note that Twirl uses a different version of the SPL vocabulary.