  The Shapes Constraint Language (SHACL) is a formal language for validating
RDF graphs against a set of conditions. Following this idea and implementing a
subset of the language, the Metadata Quality Assessment Framework provides
Shacl4Bib: a mechanism to define SHACL-like rules for data sources in non-RDF
based formats, such as XML, CSV and JSON. QA catalogue extends this concept
further to MARC21, UNIMARC and PICA data. The criteria can be defined either
with YAML or JSON configuration files or with Java code. Libraries can validate
their data against criteria expressed in a unified language, that improves the
clarity and the reusability of custom validation processes.
