(generalized-equal? *obj1 obj2* . *comparator-list*)

Compares *obj1* and *obj2* for equality in the sense of the comparators provided in comparator-list. A *comparator* is a procedure that is given two arguments to compare. It returns #t if its arguments are to be considered equal, #f if they are to be considered unequal, and the symbol pass if it cannot decide. It is an error for a comparator to return anything else. The third argument passed to a comparator is *comparator-list*, to be used in recursive calls to generalized-equal?.

The following algorithm is used to determine generalized equality:

First, if *x* and *y* are the same in the sense of eqv?, the result is #t. This keeps generalized-equal? consistent with eqv?, as equal? is.

Next, each element of *comparator-list* is invoked on *obj1* and *obj2*, passing *comparator-list* as its third argument. If the comparator returns #t or #f, that is the result.

If all comparators in *comparator-list* have been invoked with a pass result, then generalized-equal? behaves as if it had been invoked on the comparators list-comparator, string-comparator, vector-comparator, and bytevector-comparator defined below, plus additional implementation-defined comparators, if any. If all of these return pass, then generalized-equal? returns #f, as eqv? would.

When generalized-equal? is invoked with an empty comparator list, it returns what equal? returns, except possibly on implementation-defined object types that are not record types, and for the fact that generalized-equal? is not required to return when handed circular data structures. When it is invoked with numeric-comparator, char-ci-comparator, string-ci-comparator, and a comparator that descends into hash tables, it returns what Common Lisp's equalp returns.

(make-atomic-comparator *type-predicate compare-predicate*)

Returns a comparator that invokes *type-predicate* on its first and its second arguments. If they both return #t, then they are assumed to be of the same type, and *compare-predicate* is invoked on the first and second arguments together. If the result is #t or #f, then the comparator returns #t or #f respectively. If they are not of the same type, a third value is returned. The resulting comparator always ignores its third argument.

(make-specific-equality . *comparator-list*)

Return a curried version of generalized-equal? that accepts two arguments to be compared using the comparators in *comparator-list*.

(numeric-comparator *obj1 obj2 comparators-list*)

A comparator that returns #t if *obj1* and *obj2* are numbers that are equal in the sense of =, #f if they are numbers that are not equal in the sense of =, and pass otherwise. The *comparators-list* argument is ignored.

(char-ci-comparator *obj1* *obj2 comparators-list*)

A comparator that returns #t if *obj1* and *obj2* are characters that are equal in the sense of char-ci=?, #f if they are characters that are not equal in the sense of char-ci=?, and pass otherwise. The *comparators-list* argument is ignored.

(list-comparator *obj1 obj2 comparators-list*)

A comparator that returns #t if *obj1* and *obj2* are lists of the same length whose elements are equal in the sense of generalized-equal? when passed *comparators-list*, #f if they are lists that are not equal in that sense, and pass otherwise.

(string-comparator *obj1 obj2 comparators-list*)

A comparator that returns #t if *obj1* and *obj2* are strings that are equal in the sense of string=?, #f if they are strings that are not equal in the sense of string=?, and pass otherwise. The *comparators-list* argument is ignored.

(string-ci-comparator *obj1 obj2 comparators-list*)

A comparator that returns #t if *obj1* and *obj2* are strings that are equal in the sense of string-ci=?, #f if they are strings that are not equal in the sense of string-ci=?, and pass otherwise. The *comparators-list* argument is ignored.

(vector-comparator *obj1 obj2 comparators-list*)

A comparator that returns #t if *obj1* and *obj2* are vectors of the same length whose elements are equal in the sense of generalized-equal? when passed *comparators-list*, #f if they are vectors that are not equal in that sense, and pass otherwise.

(bytevector-comparator *obj1 obj2 comparators-list*)

A comparator that returns #t if *obj1* and *obj2* are bytevectors of the same length whose elements are equal in the sense of =, #f if they are bytevectors that are not equal in that sense, and pass otherwise. The *comparators-list* argument is ignored.

When used by an implementation that doesn't provide bytevectors, this procedure always returns pass.