RFC 3987 Syntax Validation

rfc3987-syntax is a Python library (current version 1.1.0) that provides helper functions to syntactically validate strings according to the ABNF grammar defined in RFC 3987, which specifies Internationalized Resource Identifiers (IRIs). It is lightweight, permissively licensed (MIT), and leverages the Lark parsing library. The project strictly focuses on ABNF syntax validation, explicitly stating that additional semantic rules (like Unicode normalization or BiDi constraints) must be handled separately. With a relatively active release cadence, its latest major update (v1.1.0) introduced support for IRI-reference and absolute-IRI.