chickadee » srfi-152 » string-any

Checks to see if every/any character in string satisfies pred, proceeding from left (index start) to right (index end). These procedures are short-circuiting: if pred returns false, string-every does not call pred on subsequent characters; if pred returns true, string-any does not call pred on subsequent characters. Both procedures are "witness-generating":

• If string-every is given an empty interval (with start = end), it returns #t.
• If string-every returns true for a non-empty interval (with start < end), the returned true value is the one returned by the final call to the predicate on (string-ref (string-copy string) (- end 1)).
• If string-any returns true, the returned true value is the one returned by the predicate.

Note: The names of these procedures do not end with a question mark. This indicates a general value is returned instead of a simple boolean (#t or #f).