;; -*- geiser-scheme-implementation: guile -*-

(define name "Jane")
(string-append "Hello, " name "!") ; "Hello, Jane!"

(define (greet name)
  (string-append "Hello, " name "!"))
                                        ;  #<unspecified>
(greet "Jane")                          ;  "Hello, Jane!"
(greet "Samantha") ;  "Hello, Samantha"

((lambda (name) (string-append "Hello, " name "!")) "Jane")
                                        ;   "Hello, Jane!"
((lambda (name) (string-append "Hello, " name "!")) "Samantha")
                                        ;  "Hello, Samantha!"

(let ((name "Horace"))
  (string-append "Hello, " name "!"))   ;   "Hello, Horace!"

(let* ((name "Horace")
       (greeting (string-append "Hello, " name "!")))
  (string-append greeting " How are you?"))
                                        ;   "Hello, Horace! How are you?"

(apply + '(1 2 5))
                                        ;    8
(define (chatty-add chatty-name . nums)
  (format #t "<~a> If you add those together you get ~a."
          chatty-name
          (apply + nums)))
(chatty-add "Jane" 1 2 5)               ;     #t

(define* (shopkeeper thing-to-buy
                     #:optional (how-many 1)
                     (cost 20)
                     #:key (shopkeeper "Sammy")
                     (store "Plentiful Great Produce"))
  (format #t "You walk into ~a, grab something from the shelves,\n" store)
  (display "and walk up to the counter.\n\n")
  (format #t "~a looks at you and says, " shopkeeper)
  (format #t "'~a ~a, eh? That'll be ~a coins!'\n" how-many thing-to-buy (* how-many cost)))
(shopkeeper "apples")
(shopkeeper "bananas" 10 28)
(shopkeeper "screws" 3 2 #:shopkeeper "Horace" #:store "Horace's Hardware")

(define (add-and-multiply x y)
  (values (+ x y) (* x y)))
(add-and-multiply 2 8)    ;  10 16

(define-values (added multiplied) (add-and-multiply 2 8))
added  ; 10
multiplied ;  16