24.5 Predicates

Function: vector-null? obj

Return #t if obj is the empty vector, otherwise return #f.

Function: %vector-every pred vec start past

Function: %vector-any pred vec start past

Macro: subvector-every pred V

Macro: subvector-any pred V

Check to see if the given predicate is true on every/any item in vec, proceeding from left (index start) to right (index past). If the selected subvector is empty, the return value is #f.

The predicate is “witness–generating”:

• If subvector-any returns true: the returned true value is the one produced by the application of the predicate.
• If subvector-every returns true: the returned true value is the one produced by the application of the predicate to the last item in the subvector.

If the predicate is applied to the final item of the selected subvector, that final application is a tail call.

The names of these procedures do not end with a question mark; this is to indicate that they do not return a simple boolean (#t or #f), but a general value.

Function: vector-every pred vec0 vec ...

Function: vector-any pred vec0 vec ...

Like subvector-every and subvector-any, but apply the predicate to the elements of all the vectors used as arguments. All the arguments must have the same number of elements.