Topic Maps Constraint Language is a programming language defined to specify constraints and schemas for topic maps.
TMCL Validator is a free and open-source project which allows you to validate a given topic map against a schema compatible to the current draft
In other words, the TMCL Validator validates a TMAPI topic map against a schema and returns a list of invalid constructs together with a description what constraint was violated.
Note: the validator does only a loose validation, i.e. constructs for which no constraint exist will be considered valid.
Detailed instructions on how to install and use the TMCL Validator utility on your Mac are available HERE.