- ievery pred ilist1 ilist2 ...procedure
Applies the predicate across the ilists, returning true if the predicate returns true on every application.
If there are n ilist arguments ilist1 ... ilistn, then pred must be a procedure taking n arguments and returning a boolean result.
ievery applies pred to the first elements of the ilisti parameters. If this application returns false, ievery immediately returns false. Otherwise, it iterates, applying pred to the second elements of the ilisti parameters, then the third, and so forth. The iteration stops when a false value is produced or one of the ilists runs out of values. In the latter case, ievery returns the true value produced by its final application of pred. The application of pred to the last element of the ilists is a tail call.
If one of the ilisti has no elements, ievery simply returns #t.
Like iany, ievery's name does not end with a question mark — this is to indicate that it does not return a simple boolean (#t or #f), but a general value.