tests whether the provided forms are strings
(string? form+) (!string? form+) (is-string form)
If all forms evaluate to string, then this function will return #t (true). The first non-string will result in the function returning #f (false).
(string? '(1 2 3 4) "hello")
This example will return #f (false) because the first form is a list.
Like most predicates, this function can also be negated by prepending the
! character. This means that all the provided forms must not be strings.
(!string? '(1 2 3) )
This example will return #t (true).