type checking for arbitrary lisp objects

[Roland Winkler]

The function bbdb-check-type performs a type checking for atomic or
compound lisp objects by comparing these objects against patterns
that use a syntax kind of similar to the :type keyword used by
defcustom (but without the extra keywords such as :tag used by
defcustom).  So a typical pattern is something like the following

   (vector (or string (const nil))
           (repeat string)
           (repeat (vector string (repeat string)
                           string string))
           (repeat (cons symbol string))
           sexp)

I am just wondering: Am I here reinventing the wheel because
something similar has been developed already in some other package?
If not, could this possibly also be useful for other packages (for
example, for defining predicates used by the safe-local-variable
property)?

Roland