type-error-datum, type-error-expected-type [Function]

type-error-datum condition => datum

type-error-expected-type condition => expected-type

Arguments and Values::

condition---a condition of type type-error.

datum---an object.

expected-type---a type specifier.

Description::

type-error-datum returns the offending datum in the situation represented by the condition.

type-error-expected-type returns the expected type of the offending datum in the situation represented by the condition.

Examples::

 (defun fix-digits (condition)
   (check-type condition type-error)
   (let* ((digits '(zero one two three four
                   five six seven eight nine))
         (val (position (type-error-datum condition) digits)))
     (if (and val (subtypep 'fixnum (type-error-expected-type condition)))
         (store-value 7))))

 (defun foo (x)
   (handler-bind ((type-error #'fix-digits))
     (check-type x number)
     (+ x 3)))

 (foo 'seven)
=>  10

See Also::

type-error, section Conditions

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