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This is a type definition for a user-defined validation block which will be called for further verification of the data (e.g. calculating the checksum) after it has passed the regular expression check.

A typical use for the validation block would be to calculate a checksum.

typedef BOOL (^RTRFieldPredicateBlock)(NSString* value);



The string with the recognized text of the field.

Return values

The block must return TRUE if the data is correct, FALSE otherwise.