CL-DATA-FORMAT-VALIDATION
CL-DATA-FORMAT-VALIDATION is provides a consistent regular interface for data conversion and validation (in the form of strings usually) into internal data types and for formatting internal data back into external presentable strings, all according to a conversion or type specification. It was created by John A.R. Williams.

ASDF-install package (obsolete) http://www.jarw.org.uk/lisp/cl-data-format-validation.tar.gz