; some useful string functions

(define x (make-string 20 #\x))
x
(string-length x)

(string=? "abc" "abc")
(string=? "abc" "ABC")
(string-ci=? "abc" "ABC")

(string->symbol "x")
(symbol->string 'x)
(string->number "100")
(number->string 100)

(string->number "1e10")

; you can specify the radix for the conversion
(string->number "100" 2)
(string->number "100" 10)
(string->number "100" 16)

; Dr. Scheme supports some extensions that are useful

(define h "hello, world")  ; string literals are considered immutable
(immutable? h)

(string-length h)
(substring h 0 5)
;(string-copy! g 0 "goodbye")
(string-upcase "abc")
(string-downcase "ABC")
(string-append "abc" "def")
(string->list "abcdef")
(list->string '(#\1 #\2 #\3 #\4 #\5))

(define hh (string-copy h))
(string-copy! hh 0 "goodbye")
hh

; Keywords beginning with a #: behave like symbols
(define x 1)
(keyword?  x)
(keyword? #:x)
(keyword->string #:x)
(string->keyword (symbol->string 'x))

(define (make-setter-name name)
  (string->symbol (string-append "set!" (symbol->string name))))

(define (make-getter-name name)
  (string->symbol (string-append "get:" (symbol->string name))))

(make-setter-name 'x)
(make-getter-name 'x)